CXA1878Q

CXA1878Q Dolby∗ B-C Type Noise Reduction System with Recording/Playback Equalizer Amplifier Description The CXA1878Q is a bipolar IC with a built-in Dolby B-C type noise reduction system (NR), Dolby S type select switch, recording/playback equalizer, electronic volume, and bias control circuit. Use of this IC in combination with two CXA1417S/Q completes a Dolby B-C-S type NR stereo system. Features • Dolby B-C type NR • Built-in filter required for recording/playback equalizer amplifiers • Recording mute function (requiring only an external time constant circuit to implement soft mute) • Fade in/out DC controllable • NORM/CrO2/METAL tape mode switching function • NORM/HIGH tape speed switching function • DC controllable for recording level calibration (approximately ±6dB variable) • DC controllable for high frequency equalizer amplifier gain (approximately ±4dB variable) • Playback deck A/B select switch • Recording volume control • Bias control circuit • Meter circuit Applications Recording/playback equalizer amplifier for stereo analog cassette decks (Applicable to ALPS ELECTRIC CO., LTD. HADKH55 series heads) 64 pin QFP (Plastic) Structure Bipolar silicon monolithic IC Absolute Maximum Ratings • Supply voltage VCC 17 V • Operating temperature Topr –20 to +75 °C • Storage temperature Tstg –65 to +150 °C • Allowable power dissipation PD 1020 mW Operating Conditions Supply voltage (VCC • VEE) ±6.5 to 8.0 V ∗ These ICs are available only to the licensees of Dolby Laboratories Licensing Corporation from whom licensing and applications information may be obtained. ∗ “Dolby” and the double D symbols are trade marks of Dolby Laboratories Licensing Corporation. Sony reserves the right to change products and specifications without prior notice. This information does not convey any license by any implication or otherwise under any patents or other right. Application circuits shown, if any, are typical examples illustrating the operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits. –1– E95933A5Z-PK Block Diagram and Pin Configuration AMS OUT NR TCH2 S IN2 REC OUT2 MT C2 NR RECIN2 NR TCL2 REC IN2 REC MUTE BS FB AMS TC S SW (S/BC/CAL) LINE OUT2 NR OUT2 NR RECOUT2 CAL IN AMS FB 51 47 34 AMS REC-EQ D GND 31 VEE 30 GND 29 28 METER2 CXA1878Q MUTE ON METER DOLBY B-C NR METER1 27 26 REC CAL PB ON GND METER1 DECK A/B 25 (A/B) B EQ 24 (NORM/CrO2/METAL) 23 GND PB 22 DVCC 21 VCC METAL NORM CrO2 REC-EQ VEE 4 7 8 5 6 9 10 11 12 13 14 15 16 17 18 19 MODE SW 20 (REC/PB) A EQ (120µ/70µ) MUTE MOA OFF CAL ON METER REC DOLBY B-C NR VOLUME CONT PB REC BAL REC VOL METER2 NR MUTE PASS OFF ON S B/C CAL DGND 32 GP CAL 42 41 39 36 33 50 44 38 49 48 45 43 46 40 37 35 VOL OUT2 52 VOLUME VOL IN2 53 NR PBIN2 54 PB OUT2 55 LINE PB INB2 56 DECK B PB EQ PB INA2 57 A GND 58 PB CAL REC REC PASS MUTE NR MOA CAL B/C S PB INA1 59 ON OFF GND A PB EQ GND ON CAL OFF PB INB1 60 B DECK PB OUT1 61 LINE NR PBIN1 62 VOL IN1 63 VOLUME VOL OUT1 64 1 2 3 S IN1 IREF MT C1 BIAS C BIAS M BIAS N NR SW (OFF/B/C) METER SW (ON/MUTE) SPEED (NS/HS) REC CAL REC IN1 NR TCH1 NR TCL1 NR OUT1 NR RECIN1 LINE OUT1 NR RECOUT1 REC OUT1 NR IREF AMS SW (OFF/AMS/BS) PASS SW (NR/MUTE/PASS) –2– CXA1878Q CXA1878Q Pin Description Pin No. Symbol Typical pin voltage (Ta = 25°C, VCC = 7.0V, VEE = –7.0V, DVCC = 5.0V) I/O Z (in) Equivalent circuit Description DC AC GND 40k 1.5k 1 51 NR RECIN1 0.0V –26dBv NR RECIN2 I 40kΩ 1 51 Recording equalizer amplifier input 300 2 50 LINE OUT1 LINE OUT2 3.4k 0.0V –4dBv O — 2 50 300 Line output 330k 3 49 NR TCH1 NR TCH2 VEE +0.4V 13k — — — 3 49 36k Time constant for the HLS 13.5k 4 48 NR TCL1 NR TCL2 VEE +0.4V — — — 4 48 480k Time constant for the LLS –3– CXA1878Q Pin No. Symbol Typical pin voltage DC AC I/O Z (in) Equivalent circuit Description 192 5 47 NR OUT1 NR OUT2 –6dBm 0.0V (–7dBv) 12k O — 5 47 20k 192 1.5k GND Dolby S type NR output 6 46 S IN1 S IN2 0.0V –6dBm (–7dBv) I 40kΩ 6 46 40k GND Dolby S type NR input 9.5k 7 45 REC IN1 REC IN2 0.0V –24dBv I 50kΩ 7 45 50k Recording equalizer amplifier input GND 211 8 44 NR RECOUT1 NR RECOUT2 –6dBm 0.0V (–7dBv) 22.5k 1.5k GND O — 8 44 211 Dolby NR recording signal output –4– CXA1878Q Pin No. Typical pin voltage Symbol DC AC I/O Z (in) Equivalent circuit Description 200 9 43 REC OUT1 REC OUT2 50k 0.0V –3dBv O — 9 43 200 Recording equalizer amplifier output 192 10 IREF VEE +1.2V — — — 10 6k Reference current setting for built-in recording/playback equalizer amplifier ∗ The reference current can be set by connecting a resistor between this pin and VEE. 8k 40k 11 NR IREF VEE +1.2V — — — 11 Reference current setting for built-in Dolby NR ∗ The reference current can be set by connecting a resistor between this pin and VEE. 300 12 40 MT C1 MT C2 0.0V — O — 14k 12 40 300 DC cut capacitance –5– CXA1878Q Pin No. Symbol Typical pin voltage DC AC I/O Z (in) Equivalent circuit Description 13 14 15 BIAS M BIAS C BIAS N — — O — 13 14 15 100k Recording bias control voltage output 16 AMS SW 2.5V when open — I — 50k 16 5k 5k 24k DGND AMS mode control ∗ Mode select switch for AMS/BS amplifier High: BS mode Medium: AMS mode Low: AMS/BS OFF mode [BS mode = Music signal interval detection during playback] [AMS mode = Music signal detection during FF/REW] 17 PASS SW 2.5V when open — I — 50k 17 5k 5k PASS mode control H : PASS M : MUTE L : NR ON DGND 10k 18 METER SW — — I — 18 DGND Meter mode control ∗ Meter amplifier output ON/OFF select switch High: Meter output OFF (mute) Low : Meter output ON –6– CXA1878Q Pin No. Typical pin voltage Symbol DC AC I/O Z (in) Equivalent circuit Description 10k 19 SPEED — — I — 19 10k DGND Tape speed selection ∗ Normal speed/ double speed selection High: Double speed Low : Normal speed 2k 6k 20 MODE SW — — I — 20 Recording/playback mode control ∗ Recording/playback mode selection High : Recording mode Low : Playback mode 21 22 VCC DVCC 7.0V 5.0V — — I I — — Positive power supply Reference power supply for mode control 23 A EQ 2.5V when open — I — 23 10k DGND Deck A playback equalizer amplifier control ∗ 120µs/70µs selection High: 70µs Low : 120µs (Built-in equalizer amplifier flat) 24 B EQ 2.5V when open — I — 10k 24 DGND Control of deck B playback equalizer amplifier mode, recording equalizer amplifier mode, and recording bias mode ∗ NORM/CrO2/METAL selection High : METAL Medium : CrO2 Low : NORM –7– CXA1878Q Pin No. Typical pin voltage Symbol DC AC I/O Z (in) Equivalent circuit Description 25 DECK A/B — — I — 10k 25 DGND Playback deck A/B select control ∗ Playback equalizer amplifier input selection High: PB INB Low : PB INA 26 27 METER1 METER2 60k 1.6V –1.1dBv O — 26 27 10k Level meter amplifier output 28 REC VOL — — I 100kΩ 60k 28 40k Recording volume level control High: Output signal level increased Low : Output signal level reduced GND 8k 8k 21k 29 REC BAL 2.5V when open 70k — I 100kΩ 29 30k DVCC/2 Recording volume balance control High : Only VOL OUT2 output level reduced Low : Only VOL OUT1 output level reduced ∗ Neither VOL OUT1 nor 2 output levels are attenuated at the control voltage of 2.5V. Connect to GND. 30 DGND 0.0V –8– CXA1878Q Pin No. 31 Symbol VEE Typical pin voltage DC –7.0V AC I/O Z (in) Equivalent circuit Description Negative power supply Recording equalizer amplifier high frequency calibration ∗ Controlled with DC voltages of 0 to 5V. High: High frequency level gain increased Low : High frequency level gain reduced ∗ Leave this pin open when not using the high frequency calibration function. Recording equalizer amplifier calibration ∗ Controlled with DC voltages of 0 to 5V. High: Recording level gain increased Low : Recording level gain reduced ∗ Leave this pin open when not using the recording calibration function. 32 GP CAL 2.5V when open — I 54kΩ 54k 32 33 REC CAL 2.5V when open — I 54kΩ 54k 33 34 NR SW 2.5V when open 2k 6k — I 50kΩ 34 50k NR control High: C type Medium: B type Low: NR OFF DVCC/2 35 S SW 2.5V when open 2k 6k — I 50kΩ 35 50k Dolby S type selection ∗ Select the calibration mode with this pin. High: CALIBRATION Medium: B-C type Low: S type DVCC/2 –9– CXA1878Q Pin No. Symbol Typical pin voltage DC AC I/O Z (in) Equivalent circuit Description 36 AMS OUT 0.0V — O — 36 10k AMS amplifier output 10k DGND 10k 37 37 AMS TC 0.0V — — — 1k 40k Time constant for the AMS 2p 38 AMS FB 0.0V — — — 38 100k Feedback during AMS mode 2p 39 BS FB 0.0V — — — 39 100k Feedback during BS mode – 10 – CXA1878Q Pin No. Typical pin voltage Symbol DC AC I/O Z (in) Equivalent circuit Description 10k GND 1.5k 41 CAL IN 0.0V –26dBv I 10kΩ 41 Calibration signal input 30k Recording mute ON/OFF selection ∗ The recording mute is controlled with DC voltages of 0 to 5V. GND 42 REC MUTE — — I — 42 ∗ Soft mute and fader functions can be set by changing the time constant of the external time constant circuit. High: Recording mute OFF Low : Recording mute ON 500 5p 64 52 VOL OUT1 VOL OUT2 0.0V –10dBv O 64 52 500 6.5k Recording volume amplifier output 63 53 VOL IN1 VOL IN2 0.0V –10dBv I 50kΩ 63 53 Recording volume amplifier input – 11 – CXA1878Q Pin No. Symbol Typical pin voltage DC AC I/O Z (in) Equivalent circuit Description Dolby NR playback input 35.5k 62 54 NR PBIN1 NR PBIN2 0.0V –11dBv I 40kΩ 2.9k 62 54 5k GND 4k GND 61 55 PB OUT1 PB OUT2 500 8p 0.0V –11dBv I — 61 55 500 30k Playback equalizer amplifier output GND 59 59 60 57 56 PB INA1 PB INB1 PB INA2 PB INB2 60 50k 0.0V –31dBv I 50kΩ 57 56 Playback equalizer amplifier input 58 GND 0.0V — — — Ground – 12 – Electrical Characteristics Measurement Circuit V3 4.2 H M L MUTE ON MUTE OFF V2 2.5 V1 0.5 Amp 2.2dB S54 R58 1k Audio SG R1 1.2k R52 1MEG CALIBRATION S52 S37 DOLBY B/C DOLBY S S51 S36 R56 1k S58 S35 DOLBY B DOLBY OFF GND DOLBY C R57 1k C47 0.1µ S31 R47 1k C44 1.0µ R49 10k R54 100k R55 1k ∗ R44 5.1k C45 1.5µ C46 0.015µ R2 1.2k GND C22 0.1µ ∗ R33 2.7k S24 ∗ R37 5.1k C38 4.7µ C40 4.7µ –7dBv –3dBv –26dBv –24dBv S26 S20 ∗ R29 86k C24 2.2µ –4dBv –26dBv –7dBv –7dBv C26 4.7µ C28 0.1µ C30 0.068µ ∗ R35 32.1k (1M//33k) C32 2.2µ C36 2.2µ C34 0.1µ S22 ∗ R31 5.1k S28 S29 ∗ R43 86k (100k// 620k) C42 2.2µ ∗ R38 2.7k ∗ R40 2.7k C41 0.1µ DC Voltmeter Amp 0dB or 30dB 51 47 34 42 41 39 36 33 50 44 38 49 48 45 43 46 40 37 35 ∗ R19 2.7k C20 4.7µ REC CAL S IN2 MT C2 BS FB CAL IN NR SW R5 100 S34 32 52 ∗ R27 S18 10k S SW S10 S57 GND NR TCH2 NR TCL2 NR OUT2 LINE OUT2 REC OUT2 GND GND 53 NR RECOUT2 ∗ R61 50k NR RECIN2 REC MUTE ∗R18 5.1k –10dBv C19 2.2µ AMS OUT R3 50k C8 0.1µ VOL OUT2 GP CAL VEE 31 REC IN2 AMS FB AMS TC S6 VOL IN2 A GND C50 10µ 30 ∗ R17 5.1k 54 S17 –10dBv C18 0.1µ DC Ammeter GND S50 S33 C7 0.1µ S9 55 R4 100 ∗ R16 2.7k ∗ R26 –11dBv 11.6k C17 (12k//330k) 1.0µ NR PBIN2 DGND ∗R15 5.1k 56 –11dBv PB OUT2 REC BAL 29 S5 GND S49 S32 S16 C16 0.1µ C6 0.1µ PB INB2 REC VOL METER2 METER1 DECK A/B B EQ A EQ DVcc Vcc 28 S4 57 ∗ R25 160k GND S56 S15 –31dBv C15 0.1µ “A” WTG C5 0.1µ ∗R24 160k 58 –31dBv PB INA2 27 +1.1dBv REC IN1 NR RECIN1 NR TCL1 LINE OUT1 NR OUT1 NR RECOUT1 IREF S IN1 REC OUT1 NR TCH1 MT C1 BIAS N BIAS M AMS SW METER SW S7 1 2 3 7 4 5 6 8 –10dBv –4dBv –7dBv –7dBv –7dBv NR IREF R6 100 –26dBv –24dBv Distortion Analyzer C23 2.2µ C29 0.068µ C35 2.2µ C25 4.7µ C27 0.1µ –3dBv ∗ R8 2.7k 9 10 11 12 13 BIAS C PASS SW 14 15 16 17 18 SPEED – 13 – GND 59 ∗R14 5.1k R60 56k 26 C52 3.3µ GND +1.1dBv S55 S3 ∗ R13 5.1k DIN Audio S14 GND C14 0.1µ R59 R61 56k 1k 25 C51 3.3µ GND S48 R68 1k S47 24 PB IN B PB IN A METAL S40 R67 1k VEE CrO2 NORMAL PB A EQ 70µ S46 23 C4 0.1µ ∗ R23 160k 60 –31dBv PB INA1 PB INB1 C13 0.1µ S2 1kHz BPF 61 –31dBv S13 C3 0.1µ ∗ R22 ∗ R12 5.1k 160k ∗ R11 2.7k C12 1.0µ 5V PB A EQ FLAT Power Supply Vcc PB OUT1 S1 62 S8 CCIR R7 100 S12 –11dBv ∗ R21 11.6k C11 (12k//330k) 0.1µ –11dBv NR PBIN1 22 A GND C49 100µ 21 DC Ammeter GND REC GND C2 0.1µ ∗R10 5.1k ∗R62 50k ∗ R9 5.1k 63 VOL IN1 A S11 64 C1 0.1µ C10 –10dBv 2.2µ AC Voltmeter ∗ R20 10k C9 1.0µ VOL OUT1 MODE SW 20 C48 100µ R66 1k 19 S45 PB DC Ammeter R65 1k S31 S38 R46 1k R48 1k S31 S38 S31 S38 R51 1k R63 1k S44 C37 4.7µ C39 2.2µ R64 1k S43 HIGH SPEED NORMAL SPEED METER MUTE METER ON PASS S53 S38 S25 S27 R42 27k MUTE DOLBY NR BS MODE Oscilloscope S19 S21 ∗R30 5.1k R32 2.7k C21 0.1µ ∗ R28 86k (100k//620k) C31 2.2µ ∗ R34 32.1k (1M//33k) S23 C33 0.1µ ∗R36 5.1k R39 2.7k R41 2.7k R45 27k C43 1.0µ S41 R62 1k I1 2mA S31 R53 100k S39 AMS MODE AMS OFF VEE CXA1878Q R50 1k Application Circuit R38 10k R8 4.7k R7 4.7k R2 –6dBv 12k R-ch R37 10k R18 2k R20 10k C28 0.47µ C12 4.7µ HP Amp R40 220 –6dBv LINE OUT HP Amp R39 220 L-ch DOLBY S NR R23 8.2k C18 2.2µ C20 0.1µ C22 0.068µ R27 1k R30 100k REC CAL R34 50k GND C34 0.1µ R28 10k R29 1MEG C24 2.2µ C27 2.2µ C29 2.2µ R24 4.7k –6dBv GND R1 12k C11 R12 4.7µ 100k –6dBv R10 100k MPX Filter R11 100k HEADPHONES –10dBv R-ch CAL OSC C31 1.0µ C33 0.015µ C32 1.5µ R16 8.2k GND LINE IN L-ch R4 15k R3 15k C10 R9 2.2µ 180k C9 2.2µ –10dBv R14 3.3k –3dBv L2 27mH 51 42 34 41 39 33 50 47 45 36 43 40 38 35 44 49 48 46 37 R6 12k C14 3.3µ GND S IN2 CAL IN NR SW AMS FB NR TCH2 NR TCL2 NR OUT2 REC IN2 LINE OUT2 REC OUT2 NR RECIN2 REC MUTE NR RECOUT2 PB Only HEAD PB Amp C7 2.2µ GND 31 53 REC CALIBRATION GP CAL R36 50k R41 50k AMS OUT VOL OUT2 GP CAL 32 AMS TC [DECK-A (R)] –31dBv 52 MT C2 BS FB S SW C2 75p REC CAL C8 150p VOL IN2 VEE VEE C39 10µ C38 10µ [DECK-A (L)] –31dBv 54 30 NR PBIN2 DGND DVCC PB Only HEAD PB Amp C6 2.2µ C16 2.2µ GND 55 PB OUT2 REC BAL 29 R33 50k C37 1µ 28 –31dBv GND 56 PB INB2 REC VOL R35 50k +1dBv C36 1µ GND [DECK-B (L)] REC 57 GND PB INA2 METER2 27 REC LEVEL & BALANSE PB Amp C5 2.2µ to AMS Control L : SIGNAL EXIST H : NO SIGNAL METER (R) +1dBv NR OUT1 PASS SW NR RECIN1 S IN1 NR RECOUT1 REC OUT1 BIAS M NR TCL1 REC IN1 LINE OUT1 IREF NR IREF BIAS C NR TCH1 MT C1 GND 1 2 3 7 4 8 5 6 9 10 11 12 13 BIAS N AMS SW METER SW 14 15 16 17 18 C1 75p C3 150p –3dBv C17 2.2µ C21 0.068µ C19 0.1µ C23 2.2µ C26 2.2µ R22 8.2k R25 27k R26 20k C30 1.0µ BIAS CONTROL R21 4.7k REC MUTE S SW NR SW DECK A/B B-DECK EQ A-DECK EQ MODE (REC/PB) SPEED METER SW PASS SW AMS/BS 19 DOLBY S NR R17 2k R19 10k Bias OSC MPX Filter R15 8.2k R31 56k C25 0.47µ C35 3.3µ R32 56k C40 3.3µ to MICROCOMPUTER L1 27mH R5 12k C13 3.3µ R13 3.3k SPEED – 14 – REC/PB HEAD [DECK-B (R)] PB REC/PB 58 GND METER1 26 METER (L) REC GND GND REC/PB HEAD [DECK-B] PB REC/PB 59 PB INA1 DECK A/B 25 –31dBv 60 PB INB1 B EQ 24 ERASE HEAD PB Amp C4 2.2µ 61 PB OUT1 A EQ 23 GND C15 2.2µ C42 10µ 62 NR PBIN1 DVCC 22 C41 10µ DVCC 63 VOL IN1 VCC 21 VCC R42 50k 64 VOL OUT1 MODE SW 20 CXA1878Q Electrical Characteristics (Ta = 25°C, VCC = 7.0V, VEE = –7.0V) Conditions Max. 48 ±8.0 V mA Unit 28 ±6.5 ±7.0 38 Min. Typ. Block Item Entire LSI Current consumption (ICC) Entire LSI Operating voltage range (positive/negative dual power supplies) Recording equalizer amplifier Recording Recording reference output equalizer amplifier level NORM-NORM mode — –3.0 Recording equalizer amplifier reference output level (315Hz) (This output level is the tape reference 0dB which generates magnetic flux of 250nWb/m) All of the recording equalizer amplifier blocks use this level as their reference level. Input level when the reference output level is 315Hz, –3.0dBv (For measurement, input a 315Hz, –24.5dBv signal to the REC EQ IN pins (Pins 7 and 45) and then measure the output level.) NORM-tape, NORM-speed mode Input a 3kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. NORM-tape, NORM-speed mode Input a 8kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. NORM-tape, NORM-speed mode Input a 12kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. CrO2-tape, NORM-speed mode Input a 3kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. CrO2-tape, NORM-speed mode Input a 8kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. CrO2-tape, NORM-speed mode Input a 12kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. METAL-tape, NORM-speed mode Input a 3kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. –26 –24.5 — dBv Recording equalizer amplifier Recording Recording reference input level equalizer amplifier NORM-NORM mode –23 dBv NORM-NORM mode Recording REC-EQ frequency response 1 equalizer amplifier (3kHz, –20dB) –1.9 –0.4 1.0 dB – 15 – NORM-NORM mode Recording REC-EQ frequency response 2 equalizer amplifier (8kHz, –20dB) 2.5 4.5 6.5 dB NORM-NORM mode Recording REC-EQ frequency response 3 equalizer amplifier (12kHz, –20dB) 7.3 10.3 13.3 dB CrO2-NORM mode Recording REC-EQ frequency response 1 equalizer amplifier (3kHz, –20dB) 2.9 4.4 5.9 dB CrO2-NORM mode Recording REC-EQ frequency response 2 equalizer amplifier (8kHz, –20dB) 7.1 9.1 11.1 dB CrO2-NORM mode Recording REC-EQ frequency response 3 equalizer amplifier (12kHz, –20dB) 11.3 14.3 17.3 dB CXA1878Q METAL-NORM mode Recording REC-EQ frequency response 1 equalizer amplifier (3kHz, –20dB) 3.9 5.4 6.9 dB Block Typ. 9.1 11.1 dB Max. Unit METAL-tape, NORM-speed mode Input a 8kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. 7.1 METAL-tape, NORM-speed mode Input a 12kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. 10.4 13.4 16.4 NORM-tape, HIGH-speed mode Input a 5kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. –1.3 0.2 NORM-tape, HIGH-speed mode Input a 15kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. 4.0 NORM-tape, HIGH-speed mode Input a 20kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. CrO2-tape, HIGH-speed mode Input a 5kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. CrO2-tape, HIGH-speed mode Input a 15kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. CrO2-tape, HIGH-speed mode Input a 20kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. METAL-tape, HIGH-speed mode Input a 5kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. METAL-tape, HIGH-speed mode Input a 15kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. METAL-tape, HIGH-speed mode Input a 20kHz signal (–20dB level down) to the REC EQ IN pin and then measure the relative deviation from NORM-NS, 315Hz mode. 7.4 6.5 1.7 dB Item Conditions Min. METAL-NORM mode Recording REC-EQ frequency response 2 equalizer amplifier (8kHz, –20dB) METAL-NORM mode Recording REC-EQ frequency response 3 equalizer amplifier (12kHz, –20dB) NORM-HIGH mode Recording REC-EQ frequency response 1 equalizer amplifier (5kHz, –20dB) dB NORM-HIGH mode Recording REC-EQ frequency response 2 equalizer amplifier (15kHz, –20dB) 9.0 dB NORM-HIGH mode Recording REC-EQ frequency response 3 equalizer amplifier (20kHz, –20dB) 10.9 14.4 dB – 16 – CrO2-HIGH mode Recording REC-EQ frequency response 1 equalizer amplifier (5kHz, –20dB) 3.9 5.4 6.9 dB CrO2-HIGH mode Recording REC-EQ frequency response 2 equalizer amplifier (15kHz, –20dB) 8.6 11.1 13.6 dB CrO2-HIGH mode Recording REC-EQ frequency response 3 equalizer amplifier (20kHz, –20dB) 11.4 14.9 18.4 dB METAL-HIGH mode Recording REC-EQ frequency response 1 equalizer amplifier (5kHz, –20dB) 5.9 7.4 8.9 dB METAL-HIGH mode Recording REC-EQ frequency response 2 equalizer amplifier (15kHz, –20dB) 9.5 12.0 14.5 dB METAL-HIGH mode Recording REC-EQ frequency response 3 equalizer amplifier (20kHz, –20dB) CXA1878Q 11.8 15.3 18.8 dB Block Min. Max. — dB 11.0 12.4 Typ. Unit NORM-tape, NORM-speed mode, RL = 2.7kΩ Input a 1kHz signal and set the output level so that THD (total harmonic distortion) is 1%. (Measure the distortion of a +11dB level-up signal.) — 0.6 0.14 % Item Conditions NORM-NORM mode Recording REC-EQ signal handling equalizer amplifier (1kHz, THD = 1%, RL = 2.7kΩ) NORM-tape, NORM-speed mode, RL = 2.7kΩ NORM-NORM mode Recording REC-EQ total harmonic distortion Input a 1kHz, 0dB (reference input level) signal and measure the distortion. equalizer amplifier (Measure the distortion as THD + N.) (1kHz, 0.0dB, RL = 2.7kΩ) NORM-tape, NORM-speed mode, Rg = 5.1kΩ With no signal, measure the noise using the “A”-WGT filter. (The measured value is indicated as the relative value compared to the reference level.) 57.0 65.0 NORM-tape, NORM-speed mode With no signal, measure the DC offset voltage of the REC OUT pin. –500 10.0 — NORM-NORM mode Recording REC-EQ S/N ratio equalizer amplifier (“A”-WGT filter) dB NORM-NORM mode Recording Output DC offset voltage equalizer amplifier (REC OUT pin) — 500 mV NORM-tape, NORM-speed mode, REC-MUTE = 0.5V NORM-NORM mode Recording REC-EQ mute characteristics 1 Input a 1kHz signal (+12dB level up) and measure the attenuation equalizer amplifier when REC MUTE is ON. (Use a 1kHz BPF.) (REC-MUTE = 0.5V) –99.9 –80 dB – 17 – NORM-tape, NORM-speed mode, REC-MUTE = 2.5V NORM-NORM mode Recording REC-EQ mute characteristics 2 Input a 1kHz, 0dB (reference level) signal and measure the attenuation –8.1 equalizer amplifier characteristics curve of the soft mute function (when REC-MUTE = 2.5V). (REC-MUTE = 2.5V) 4.8 –6.6 –5.1 dB NORM-tape, NORM-speed mode, REC-CAL = 5.0V NORM-NORM mode Recording REC-EQ REC-CAL characteristics 1 Input a 315Hz signal (–20dB level down) and measure the amount of change equalizer amplifier compared to when the REC-CAL function is at the standard setting. (REC-CAL = 5.0V) 6.3 7.8 dB NORM-tape, NORM-speed mode, REC-CAL = 0.0V NORM-NORM mode Recording REC-EQ REC-CAL characteristics 2 Input a 315Hz signal (–20dB level down) and measure the amount of change equalizer amplifier compared to when the REC-CAL function is at the standard setting. (REC-CAL = 0.0V) –7.5 –6.0 –4.5 dB NORM-tape, NORM-speed mode, Gp-CAL = 5.0V NORM-NORM mode Recording REC-EQ Gp-CAL characteristics 1 Input a 8kHz signal (–20dB level down) and measure the amount of change equalizer amplifier compared to when the Gp-CAL function is at the standard setting. (Gp-CAL = 5.0V) 2.7 4.2 5.7 dB NORM-tape, NORM-speed mode, Gp-CAL = 0.0V NORM-NORM mode Recording REC-EQ Gp-CAL characteristics 2 Input a 8kHz signal (–20dB level down) and measure the amount of change equalizer amplifier compared to when the Gp-CAL function is at the standard setting. (Gp-CAL = 0.0V) –4.8 –3.3 –1.8 dB REC-VOL = 5.0V, REC-BAL = 2.5V Recording volume amplifier Recording volume Recording volume characteristics 1 Input a 1kHz, –10dBv signal to the VOL IN pin and measure the full (REC-VOL = 5.0V, REC-BAL = 2.5V) gain of the recording volume amplifier. CXA1878Q 8.0 9.0 10.0 dB Block Min. Max. –7.4 dB –9.4 –8.4 Typ. Unit Item Conditions REC-VOL = 2.0V, REC-BAL = 2.5V Recording volume amplifier Recording volume Recording volume characteristics 2 Input a 1kHz, –10dBv signal to the VOL IN pin and measure the (REC-VOL = 2.0V, REC-BAL = 2.5V) attenuation of the recording volume amplifier. — –80 –104.7 dB REC-VOL = 0.0V, REC-BAL = 2.5V Recording volume amplifier Recording volume Recording volume attenuation Input a 1kHz, +2dBv signal and measure the maximum volume (REC-VOL = 0.0V, REC-BAL = 2.5V) attenuation of the recording volume amplifier. (Use a 1kHz BPF.) 2.0 3.41 — REC-VOL = 2.0V, REC-BAL = 2.5V, RL = 2.7kΩ Recording volume amplifier Input a 1kHz signal and set the input level so that the THD is 1%. Recording volume REC-VOL signal handling (1kHz, THD = 1%, RL = 2.7kΩ) (Measure the distortion when the output is +2dBv.) — 0.09 dBv REC-VOL = 2.0V, REC-BAL = 2.5V, RL = 2.7kΩ Recording volume amplifier Recording volume REC-VOL total harmonic distortion Input a 1kHz, –10dBv signal (reference input level) and measure the distortion. (Measure the distortion as THD + N.) (1kHz, –6.0dBv, RL = 2.7kΩ) REC-VOL = 5.0V, REC-BAL = 2.5V With no signal, measure the noise using an “A”-WGT filter. (The measured value is indicated as the relative value compared to the full-gain level.) REC-VOL = 5.0V, REC-BAL = 2.5V With no signal, measure the DC offset voltage of the VOL OUT pin. 80 0.5 % Recording volume amplifier Recording volume REC-VOL S/N ratio (“A”-WGT filter) 97.5 — dB – 18 – Recording volume amplifier Recording volume Output DC offset voltage (VOL OUT pin) –150 4.2 150 mV REC-VOL = 5.0V, REC-BAL = 0.0V, (1kHz BPF) Recording volume amplifier Recording volume REC-VOL balance characteristics 1 Input a 1kHz, +2dBv signal and measure the attenuation of VOL OUT 1. (REC-VOL = 5.0V, REC-BAL = 0.0V) (Input a –10dBv signal and confirm that there is no attenuation at VOL OUT 2.) — –93.2 –60 dB REC-VOL = 5.0V, REC-BAL = 5.0V, (1kHz BPF) Recording volume amplifier Recording volume REC-VOL balance characteristics 2 Input a 1kHz, +2dBv signal and measure the attenuation of VOL OUT 2. (REC-VOL = 5.0V, REC-BAL = 5.0V) (Input a –10dBv signal and confirm that there is no attenuation at VOL OUT 1.) — –93.2 –60 dB Line amplifier Line amplifier NR mode NR mode gain Input a 1kHz, –11dBv signal to the NR PB IN pin and measure the gain. (NR PB IN = 1kHz, –11.0dBv) 6.0 7.0 8.0 dB Line amplifier Line amplifier PASS mode PASS mode gain Input a 1kHz, –11dBv signal to the NR PB IN pin and measure the gain. (NR PB IN = 1kHz, –11.0dBv) 6.0 7.0 8.0 dB CXA1878Q Line amplifier PASS mode, RL = 2.7kΩ Line amplifier Input a 1kHz signal and set the output level so that the THD is 1%. Signal handling (1kHz, THD = 1%, RL = 2.7kΩ) (Measure the distortion when the output is +1dBv.) 12.0 15.5 — dB Block Min. Max. 1.0 % — 0.07 Typ. Unit Item Conditions Line amplifier PASS mode, RL = 2.7kΩ Line amplifier Line amplifier total harmonic distortion Input a 1kHz, –11dBv signal (reference input level) and measure the (1kHz, –11.0dBv, RL = 2.7kΩ) distortion. (Measure the distortion as THD + N.) PASS mode, Rg = 5.1kΩ With no signal, measure the noise using the “A”-WGT filter. (The measured value is indicated as the relative value compared to the reference level. 80 — 84.1 PASS mode With no signal, measure the DC offset voltage of the LINE OUT pin. –200 0 200 dB Line amplifier Line amplifier Line amplifier S/N ratio (“A”-WGT filter) Line amplifier Line amplifier Output DC offset voltage (LINE OUT pin) MUTE mode Input a 1kHz, +1dBv signal to the NR PB IN pin and measure the attenuation when LINE MUTE is on. (Use a 1kHz BPF.) — METER ON, CAL OFF, PB Input a 1kHz, –11dBv signal to the NR PB IN pin and measure the output DC voltage at the METER pin. METER ON, CAL OFF, PB Input a 1kHz, –21dBv (–10dB level down) signal to the NR PB IN pin and measure the output DC voltage at the METER pin. 1.34 –111 mV Line amplifier Line amplifier MUTE mode characteristics (1kHz BPF) –80 dB Level meter Level meter amplifier Level meter characteristics 1 (PASS IN = 1kHz, –11dBv) 1.64 1.94 V – 19 – Level meter Level meter amplifier Level meter characteristics 2 (PASS IN = 1kHz, –21dBv) 0.2 0.5 0.8 V Level meter METER ON, CAL ON, REC Level meter amplifier Level meter CAL characteristics Input a 1kHz, –28dBv (–17dB level down) signal to the NR PB IN pin and measure the output DC voltage at the METER pin. (PASS IN = 1kHz, –28dBv) 1.3 1.6 1.9 V Level meter METER MUTE ON, PB Level meter amplifier Level meter MUTE characteristics Input a 1kHz, +1dBv (12dB level up) signal to the NR PB IN pin and measure the output DC voltage at the METER pin. (PASS IN = 1kHz, +1.0dBv) — 3.0 50.0 mV DECK-A, A-EQ = 120µs, NORM-speed mode 120µs, DECK-A mode Playback Playback reference output level Input a 315Hz, –31dBv (reference input level) signal to the PB IN pin equalizer amplifier (Playback equalizer amplifier gain) and measure the output level. DECK-A, A-EQ = 120µs, NORM-speed mode Input a 5kHz, –31dBv (reference input level) signal and then measure the relative deviation from the 120µs-NS, 315Hz mode. DECK-A, A-EQ = 70µs, NORM-speed mode Input a 5kHz, –31dBv (reference input level) signal and then measure the relative deviation from the 120µs-NS, 315Hz mode. –11.9 –10.9 –9.9 dBv Playback equalizer amplifier Playback PB-EQ frequency response 1 equalizer amplifier 120µs-NS, DECK-A mode –1.0 0.0 1.0 dB Playback equalizer amplifier Playback PB-EQ frequency response 2 equalizer amplifier 70µs-NS, DECK-A mode CXA1878Q –5.7 –4.2 –2.7 dB Block Typ. –5.3 –3.8 dB Max. Unit DECK-A, A-EQ = 120µs, HIGH-speed mode Input a 5kHz, –31dBv (reference input level) signal and then measure the relative deviation from the 120µs-NS, 315Hz mode. –6.8 DECK-A, A-EQ = 70µs, HIGH-speed mode Input a 5kHz, –31dBv (reference input level) signal and then measure the relative deviation from the 120µs-NS, 315Hz mode. –10.1 –7.1 –8.6 12 22 — dB Item Conditions Min. Playback equalizer amplifier Playback PB-EQ frequency response 3 equalizer amplifier 120µs-HS, DECK-A mode Playback equalizer amplifier Playback PB-EQ frequency response 4 equalizer amplifier 70µs-HS, DECK-A mode DECK-A, A-EQ = 120µs, NORM-speed mode, RL = 2.7kΩ 120µs-NS, DECK-A mode Playback Input a 1kHz signal and set the output level so that the THD is 1%. PB-EQ signal handling equalizer amplifier (1kHz, THD = 1%, RL = 2.7kΩ) (Measure the distortion of a +12dB level-up signal.) — 0.03 dB DECK-A, A-EQ = 120µs, NORM-speed mode, RL = 2.7kΩ 120µs-NS, DECK-A mode Playback PB-EQ total harmonic distortion Input a 1kHz, –31dBv (reference input level) signal and measure the equalizer amplifier distortion. (Measure the distortion as THD + N.) (1kHz, 0.0dB, RL = 2.7kΩ) DECK-A, A-EQ = 120µs, NORM-speed mode, Rg = 5.1kΩ With no signal, measure the noise using the “A”-WGT filter. (The measured value is indicated as the relative value compared to the reference level.) DECK-A, A-EQ = 120µs, NORM-speed mode With no signal, measure the DC offset voltage of the PB OUT pin. 70 0.5 % 120µs-NS, DECK-A mode Playback PB-EQ S/N ratio equalizer amplifier (“A”-WGT filter) 75.6 — dB – 20 – 120µs-NS, DECK-A mode Playback Output DC offset voltage equalizer amplifier (PB OUT pin) –200 –5 200 mV Recording equalizer amplifier DECK-A/B switching Playback equalizer amplifier characteristics 120µs-NS, DECK-B mode DECK-B, B-EQ = NORM-tape, NORM-speed mode Input a 1kHz, –31dBv (reference input level) signal to the DECK-B side and then measure the relative deviation from the DECK-A, 120µs-NS, 315Hz mode. –1.0 0.0 1.0 dB AMS/BS amplifier AMS/BS amplifier AMS signal detection level AMS mode AMS mode, fin = 5kHz, reference level –11dBv Input level when the AMS OUT pin level changes from high to low. Input the signal to the NR PB IN pin and measure the level at the AMS OUT pin. –15.0 –10.0 –5.0 dB AMS/BS amplifier AMS/BS amplifier BS signal detection level BS mode BS mode, fin = 5kHz, reference level –11dBv Input level when the AMS OUT pin level changes from high to low. Input the signal to the NR PB IN pin and measure the level at the AMS OUT pin. AMS OFF mode Input a 5kHz, –11dBv signal to the NR PB IN pin and measure the current flowing to the AMS OUT pin. –35.5 –30.5 –25.5 dB CXA1878Q AMS/BS amplifier AMS/BS amplifier AMS output leak current (AMS OUT pin) — 0.88 1.0 µA Block Min. Max. 1.0 V — 0.17 Typ. Unit Item Conditions AMS/BS amplifier AMS mode AMS/BS amplifier AMS output saturation voltage Input a 5kHz, –11dBv signal to the NR PB IN pin and measure the output voltage when a 1mA current flows to the AMS OUT pin. (AMS OUT pin) Input a 2mA signal to the BIAS N pin and measure the DC output voltage at the BIAS N pin. — 0.4 0.4 0.4 –6.0 0.6 0.6 — 0.6 — — — Input a 2mA signal to the BIAS C pin and measure the DC output voltage at the BIAS C pin. Input a 2mA signal to the BIAS M pin and measure the DC output voltage at the BIAS M pin. REC mode, NR OFF 1kHz, assume Dolby level of –6dBm as 0dB. REC mode, NR OFF, f = 1kHz Input a signal to the REC IN pin and measure the level at which the level of the DOLBY OUT pin reaches –6dBm. REC mode, NR OFF, f = 1kHz Input a signal to the CAL IN pin and measure the level at which the level of the DOLBY OUT pin reaches –6dBm. PB mode, NR OFF, f = 1kHz Input a signal to the NR PB IN pin and measure the level at which the level of the DOLBY OUT pin reaches –6dBm. REC, Dolby B type mode Input a 500Hz, –25dB signal from the REC IN pin and measure the boost at the REC OUT pin. REC, Dolby B type mode Input a 5kHz, –25dB signal from the REC IN pin and measure the boost at the REC OUT pin. REC, Dolby B type mode Input a 10kHz, –40dB signal from the REC IN pin and measure the boost at the REC OUT pin. REC, Dolby B type mode Input a 10kHz, 0dB signal from the REC IN pin and measure the boost at the REC OUT pin. V V V dBm BIAS SW BIAS N output voltage (NORMAL mode) BIAS SW BIAS C output voltage (CrO2 mode) BIAS SW BIAS M output voltage (METAL mode) DOLBY Dolby level DOLBY REC mode REC IN level –26 –25 –24 dBm – 21 – DOLBY REC mode CAL IN level –26 –25 –24 dBm DOLBY PB mode PB IN level –11 –10 –9 dBm DOLBY B type encoding Boost characteristics 1 1.4 2.9 4.4 dB DOLBY B type encoding Boost characteristics 2 3.9 5.4 6.9 dB DOLBY B type encoding Boost characteristics 3 9.7 10.4 11.4 dB CXA1878Q DOLBY B type encoding Boost characteristics 4 –1.1 0.4 1.9 dB Block Min. 14.2 16.2 18.2 dB Typ. Max. Unit REC, Dolby C type mode Input a 500Hz, –60dB signal from the REC IN pin and measure the boost at the REC OUT pin. REC, Dolby C type mode Input a 500Hz, –25dB signal from the REC IN pin and measure the boost at the REC OUT pin. 7.2 9.2 11.2 REC, Dolby C type mode Input a 2kHz, –60dB signal from the REC IN pin and measure the boost at the REC OUT pin. 18.7 20.7 REC, Dolby C type mode Input a 2kHz, –25dB signal from the REC IN pin and measure the boost at the REC OUT pin. 5.4 REC, Dolby C type mode Input a 5kHz, –25dB signal from the REC IN pin and measure the boost at the REC OUT pin. REC, Dolby C type mode Input a 10kHz, 0dB signal from the REC IN pin and measure the boost at the REC OUT pin. PB, Dolby C type mode Input a 20kHz, –10dBm signal from the NR PB IN pin and measure the relative deviation from the REC OUT output NR OFF mode. REC, NR OFF mode Input a 1kHz signal and set the output level so that the THD is 1%. (Measure the distortion using a +13.5dB level-up signal from the reference.) REC, NR OFF mode Input a 1kHz, +10dB signal from the REC IN pin and measure the distortion. (Measure the distortion as THD + N.) REC, Dolby B type mode Input a 1kHz, +10dB signal from the REC IN pin and measure the distortion. (Measure the distortion as THD + N.) REC, Dolby C type mode Input a 1kHz, +10dB signal from the REC IN pin and measure the distortion. (Measure the distortion as THD + N.) 3.5 7.4 22.7 dB Item Conditions DOLBY C type encoding Boost characteristics 1 DOLBY C type encoding Boost characteristics 2 DOLBY C type encoding Boost characteristics 3 dB DOLBY C type encoding Boost characteristics 4 9.4 dB DOLBY C type encoding Boost characteristics 5 5.5 7.5 dB – 22 – DOLBY C type encoding Boost characteristics 6 –5.5 –3.5 –1.5 dB DOLBY PB mode Frequency response –1.5 0 1.5 dB DOLBY REC mode Signal handling 13.5 15.4 — dB DOLBY NR OFF total harmonic distortion — 0.04 0.5 % DOLBY Dolby B type total harmonic distortion — 0.06 0.5 % CXA1878Q DOLBY Dolby C type total harmonic distortion — 0.09 0.5 % Block Conditions Typ. Max. Unit Min. Item DOLBY 61.0 — REC mode Dolby C type S/N ratio 60.0 dB REC, Dolby C type mode, Rg = 5.1kΩ With no signal, measure the noise using the CCIR/ARM filter. (The measured value is indicated as the relative value compared to the DOLBY OUT level.) PB, NR OFF mode Input a 1kHz, +10dB signal from the REC IN pin and measure the REC → PB crosstalk. (Use a 1kHz BPF.) — –77.5 –70 REC, NR OFF mode Input a 1kHz, +10dB signal from the NR PB IN pin and measure the PB → REC crosstalk. (Use a 1kHz BPF.) — REC mode, NR OFF → C type With no signal, measure the deviation in the output DC offset voltage at –100 the REC OUT pin when switching from NR OFF mode to C type mode. NR SW, S SW, DECK A/B, EQ, B EQ, and PASS SW pin voltages 4.2 2.2 0.0 3.5 0.0 0.0 –113 –70 dB DOLBY PB mode Recording → playback crosstalk DOLBY REC mode Playback → recording crosstalk dB DOLBY REC mode Output DC offset voltage (REC OUT pin) 100 mV Control circuit Mode control Control circuit high level — — — — — VCC 2.8 0.5 VCC 0.5 V V V V V Binary swithing Ternary switching – 23 – Control circuit Mode control NR SW, S SW, DECK A/B, EQ, B EQ, and PASS SW pin voltages Control circuit medium level NR SW, S SW, DECK A/B, EQ, B EQ, and PASS SW pin voltages AMS SW, MODE SW, SPEED, and METER SW pin voltages AMS SW, MODE SW, SPEED, and METER SW pin voltages Control circuit Mode control Control circuit low level Control circuit Mode control Control circuit high level Control circuit Mode control Control circuit low level CXA1878Q OSC GND R20 2k (–6dBm) GND C12 2.2µ R34 8.2k C14 2.2µ R35 4.7k R37 10k –6dBv GND 600 10k to LINE IN C13 0.47µ ∗ Sourse Impedance 10kΩ C6 2.2µ –26dBv GND –14dBv R18 6.2k DOLBY S NR R15 3.3k MPX Filter NR RECIN R21 10k VGS (C) VGS (C) R41 20k –7dBv REC R23 PB –3dBv (–6dBm) VGS (C) R40 15k R31 40k ON –24dBv R38 50k –0.5dBv GND (A) L-ch CAL IN Bias OSC VGS (B) C24 75p R4 15k VOL IN –10dBv Gm1 VOL OUT NR OUT S IN –10dBv –10dBv LINE IN for R-ch C8 OFF R57 40k ×1 Gm2 Gm5 REC OUT REA R53 8k GND R63 50k R56 24k C23 150p L1 27mH C22 R66 3.3µ 12k C17 200p –7dBv C3 R7 2.2µ 50k R3 GND 180k GND GND R12 6.5k R13 6.5k VGS (C) R17 40k NR RECOUT REC IN REC A EQ (120/70) REC/PB HEAD ×1 R-ch MOA REC/PB PB VGS (C) R25 1.5k +6dBv C20 100p GND Gm4 (A) DVcc VGS (C) R65 50k R67 50k VGS (C) VGS (C) –7dBv R22 1.5k R24 22.5k –7dBv (–6dBm) R51 20k –6dBv (–6dBm) –7dBv METER ON BC/S/CAL CAL OFF R43 2.5k R52 20k R26 12k VGS (C) BPF –6dBv REC & CAL RVA B EQ (N/C/M) R19 4k VGS (C) VGS VGS (C) (B) –26dBv (–25dBm) for R-ch SPEED (NS/HS) DVcc DECK A/B (A/B) (–30dBm) –31dBv R16 36k [DECK-B] R2 50k REC MUTE Gm3 ×1 PB REC/PB REC VOL R1 50k REC BAL PASS SW (NR/MUTE/PASS) CONTROL REC GND METER SW (ON/MUTE) Dolby B/C-NR ANTS ×1 REC CAL CALIBRATION Vcc GND (A) C19 100p GND MODE SW (REC/PB) CAL S-NR B/C-NR PB Amp NR SW (OFF/B/C) HLS VF LLS VF OFF to Control IC –7dBv (–6dBm) VGS (B) ON GND R47 12k R46 2k B EQ METAL CrO2 NORM OFF ON CAL OFF METER S SW (S/BC/CAL) AMS SW (OFF/AMS/BS) SSK METER S SW ON GP CAL Vcc Vcc GND VEE VEE GND GND (VG) Q BIAS-N Description of Operation The CXA1878Q is a Dolby B-C type NR system with a built-in recording/playback equalizer amplifier, electronic volume, AMS, BIAS SW, and meter circuit. In addition, this chip also contains an S type (CXA1417S/Q) select switch, enabling the construction of a 2-channel Dolby B-C-S type NR system by using the CXA1878Q together with two CXA1417S/Q encoder units. The CXA1878Q has the circuit configuration shown in Fig. 1. – 24 – –11dBv NR/PASS/MUTE VGS NR LINE (C) PASS –4dBv MUTE R54 14k VGS (B) PASS R27 40k R28 12.5k VGS R39 5k (C) R42 2.9k R29 100k R44 3.3k –11dBv R23 40k MUTE NR NR/PASS /MUTE VEE IREF (REC/PB) BIAS for R-ch R6 27k DVCC DVcc Q VEE BIAS-C GND DGND BIAS CONTROL VEE R59 10k VEE NR IREF BIAS-M MTR R58 36k DGND R60 10k R5 20k VGS (C) PB Only HEAD ×1 DET –26dBv –15dBv C2 2.2µ PB INA A DECK ×1 AMS DGND R32 100k –15dBv DGND BS R9 50k R14 30k Q Q COMP –31dBv –15dBv VGS C10 (B) SUM 106p VEE AMS/BS AMS [DECK-A] PB Amp C1 D1 B DECK –11dBv –11dBv DVcc R64 100k –11dBv 2.2µ PRE VEE R62 150 +1.1dBv (1.6V) PB INB Gmb PEA AMS OUT GND –31dBv R8 50k R10 2k R11 18k C4 200p GND (A) to AMS Control (–10dBm) –11dBv –4dBv VGS (C) VGS (C) PB OUT NR TCH AMS FB R30 10k R33 1k C11 1.5µ GND GND R36 1MEG C9 0.015µ NRPB IN BS FB C7 0.1µ VEE VEE C8 0.068µ NR TCL AMS TC LINE OUT C16 4.7µ MT C METER to METER IC C5 2.2µ C15 0.1µ L-ch R45 12k –6dBv C18 1.0µ for R-ch LINE OUT R50 4.7k R48 GND 100k R49 10k GND R55 220 R61 56k C21 3.3µ GND GND –6dBv DVcc DVcc from LINE OUT R-ch for R-ch GND GND VM HP Amp GND HEADPHONES 47k GND ∗ Load Impedance 47kΩ CXA1878Q Fig. 1. Functional block diagram CXA1878Q 1. Reference levels (1) Recording equalizer amplifier output level (315Hz, –3dBv) [∗ when the recording equalizer amplifier input level is –24dBv] (2) Playback equalizer amplifier output level (315Hz, –11dBv) [∗ when the playback equalizer amplifier input level is –31dBv] (3) Dolby The Dolby level is measured at the recording output pin (REC OUT) at –6dBm (388mVrms) in the NR OFF mode. Reference levels for the recording input pin (LINE IN), playback input pin (PB IN) and line output pin (LINE OUT) are defined as the levels which apply the Dolby level to REC OUT in the NR OFF mode. 2. System control methods (1) Mode settings table Pin No. 34 35 16 20 19 25 23 Symbol NR SW NR S SW AMS SW MODE SW SPEED DECK A/B A EQ Pin voltage Low DOLBY NR OFF DOLBY S AMS OFF PB NORMAL SPEED PB IN A PB IN A EQ FLAT PB IN B EQ FLAT 24 B EQ REC EQ NORMAL BIAS SW NORMAL 17 18 PASS SW METER SW DOLBY NR METER ON Medium DOLBY NR ON B type DOLBY B-C∗ AMS MODE — — — — PB IN B EQ 70µ REC EQ CrO2 BIAS SW CrO2 MUTE — High DOLBY NR ON C type CALIBRATION BS MODE REC HIGH SPEED PB IN B PB IN A EQ 70µ PB IN B EQ 70µ REC EQ METAL BIAS SW METAL PASS METER OFF 3-state 2-state 3-state 3-state 3-state 3-state 2-state 2-state 2-state 2-state Remarks Note: When 3-state input pins are open, the pin voltage is medium. ∗ The NR SW (Pin 34) operates only when the NR S SW (Pin 35) is set to medium. (2) Mode setting pin control voltage Control voltage High level 3-state Medium level Low level 2-state High level Low level Min. 4.2 2.2 0.0 3.5 0.0 Max. VCC 2.8 0.5 VCC 0.5 – 25 – CXA1878Q 3. Recording mute function The CXA1878Q recording mute function is implemented by using a built-in recording mute circuit which varies the recording equalizer amplifier gain according to the magnitude of the DC voltage applied to the REC MUTE pin just like an electronic volume control. Also, any desired soft mute or fader can be freely set depending on momentary changes in the DC voltage applied to the REC MUTE pin. Fig. 2 illustrates the recording mute waveforms. Fig. 2. Recording mute waveform REC MUTE control voltage Pin No. Symbol Pin voltage (V) 0.0 0.5 2.5 4.5 5.0 Remarks Decrease