900BT

Models 900CT & 900BT Tunable Active Filter Instrument Single Channel – Certified Description Frequency Devices’ Models 900CT & 900BT instruments are single channel; 8-pole low-pass or high-pass, front panel tunable filter instruments. The controls allow the user to select a corner frequency between 0.1 Hz and 49.9 kHz with a resolution of 1:499 for each of the four selectable ranges. The instrument exhibits an input impedance of 1 MΩ shunted by 47pF to a single ended signal source. When configured in the differential mode, the instrument has a common mode rejection ratio (CMRR), which exceeds 60dB; in this mode the instrument presents an input impedance of 2 MΩ’s shunted by 47pF to a double-ended single source. Front panel gain control also enables the operator to select a gain factor of 0, 10, or 20dB. Standard operational features include: 1) Adjustable Frequency Control 2) Differential Input Amplifiers 3) Adjustable Gain Control 4) Off-set Adjustment 5) Bypass Control 6) BNC Connectors for Signal I/O The optional battery powered 900BT is particularly well suited to applications requiring isolation from an electrically noisy primary power source. Compact size and manual rotary switch front panel controls make 900 instruments a popular, cost effective, easy-to-use solution for signal conditioning applications in the following areas: Anti-aliasing Filters Biomedical/Biotechnology Applications Data Recording/Playback Data Smoothing EKG/EEG Signal Filtering FDM/PCM Signal Filtering Medical Research Industrial Process Control Seismic Analysis Vibration Analysis Models 900CT 900BT Standard AC Powered AC Powered, with battery option Available Low-Pass Filters: Part# #Poles 900L8B 8 900L8L 8 900L8E 8, 6 zero 900L8EY 8, 6 zero 900L8D80 8, 6 zero 900L8D100 8, 6 zero Available High-Pass Filters: Part# #Poles 900H8B 8 900H8E 8, 6 zero 900H8EY 8, 6 zero Filter Type Page Butterworth 6 Bessel 6 Elliptic, 1.77 6 Elliptic, 2.00 6 Constant Delay 7 Constant Delay 7 Filter Type Butterworth Elliptic, 1.77 Elliptic, 2.00 Page 8 8 8 2 4&5 9 10 Block Diagram Front & Rear panel descriptions General Specifications: Ordering Information 1 1784 Chessie Lane, Ottawa, IL 61350 • Tel: 800/252-7074, 815/434-7800 • FAX: 815/434-8176 e-mail: sales@freqdev.com • Web Address: http://www.freqdev.com Models 900CT & 900BT Model 900 Series Instrument Block Diagram BLOCK DIAGRAM GAIN (dB) Single Channel – Certified INPUT 10dB 0dB 20dB A-B A + DIFF AMP OFFSET NULLED BYPASS CORNER FREQUENCY TUNING OFFSET TYPICAL ADJUSTMENT FUNCTION OUT A 8-POLE TUNABLE FILTER OUTPUT AMP B TYPICAL FRONT PANEL BNC CONNECTOR 1 0 2 3 CORNER FREQUENCY HZ 5 5 4 4 6 4 3 2 1 0 9 7 8 3 2 1 6 7 0.1 8 9 MULTIPLIER 10 1 100 0 FRONT PANEL 2 1784 Chessie Lane, Ottawa, IL 61350 • Tel: 800/252-7074, 815/434-7800 • FAX: 815/434-8176 e-mail: sales@freqdev.com • Web Address: http://www.freqdev.com Models 900CT & 900BT Model 900 Series Initial Setup Procedure The B, C and D switches combined can select base corner frequency values ranging from 1 to 499 Hz in 1 Hz steps with switch weightings as just described. The accuracy of the corner frequency is improved by selecting the largest possible base frequency and down scaling by the MULTIPLIER. The greatest accuracy is obtained with the largest base 400, and the 0.1X MULTIPLIER switch setting. Relative accuracy of selected 40 Hz actual corner frequency for different multiplier switch settings. BASE FREQ Msd C 0 4 0 X MULT Lsd E 0.1X 1X 10X RELATIVE TUNING ACCURACY Single Channel – Initial Setup Certified Set the OFFSET control for a zero-volt reading on the scope or DVM. Subsequent changes of CORNER FREQUENCY and GAIN control settings will introduce a small dc output offset, which should be zeroed for critical applications. Leaving all other controls unchanged, set the Input Switch to (A-B) and apply a 5Vdc signal simultaneously to input BNCs (A) and (B). The voltage measured at the OUT BNC should be 5 - 5 = 0 Vdc. This completes preliminary test and adjustment. Corner Frequency Selection To select a corner frequency, simply set the CORNER FREQUENCY switches and the MULTIPLIER switch for the desired numerical value. Select desired operating voltage 115 Vac or 230 Vac. See note "Q" on Page 5. Set the POWER ON/OFF Switch to ON. A continuously lit POWER lamp indicates proper internal DC voltages, an essential requirement for battery-powered models. Allow the instrument a three-minute warm-up period to achieve thermal equilibrium. To perform initial adjustment and/or operational testing, set the remaining front panel controls as follows: a) The three base CORNER FREQUENCY switches and the MULTIPLIER to the desired corner frequency… b) The OFFSET control to approximately mid-range… c) The GAIN switch to the desired value… d) The BYPASS switch to OUT… e) The INPUT switch to ground ( ). Connect a dc-coupled oscilloscope, of vertical sensitivity 10mV/CM or better, or a digital voltmeter (DVM) to the instrument front panel BNC connector labeled OUT. B 4 0 0 D 0 0 4 GREATEST LESS LEAST The CORNER FREQUENCY switch weightings follow standard decimal positional conventions. Circuit model illustrating the relationship between a filter’s differential input and amplifier and external signal and error sources. DIFFERENTIAL INPUT AMPLIFIER 0d The differential input The instrument input utilizes a differential input amplifier to reject prevalent forms of electrical interference, while presenting desirable input characteristics to the signal source requiring filtering. The differential input configuration is ideal for measuring the difference between two values rather than the values themselves. Bridge circuits utilizing strain gages, thermocouples and a variety of other types of transducers generate differential full-scale output voltages in the order of millivolts that are often superimposed upon volt-level reference and noise values. The importance of CMRR In actual system environments, each signal and power return conductor can generate an interference voltage proportional to the net conductor resistance and the electrical current level. Any such interference voltages appear as common mode signals to the amplifier, and are rejected as such. INPUT SIGNAL AND NOISE VOLTAGE SOURCES R SA B 10 dB A (+) 20 dB * GAIN = K + DIFF AMP OUT V A VCM VB RCM+ RD SIGNAL COMMON RSB RCM(-) FILTER/ BYPASS OUTPUT AMPLIFER B -Vs COM Vo = K(VA - VB) + Vcm/CMRR : WHERE K = 1, 10 AND 10 FOR GAIN SETTINGS OF 0, 10 AND 20dB RESPECTIVELY. +Vs SEE TEXT FOR REMAINING TERMS. (+) COUPLED POWER LINE NOISE VOLTAGE (-) * DENOTES FRONT PANEL ACCESS AC POWER SUPPLY VP OR INTERNAL BATTERIES SIGNAL COMMON 3 1784 Chessie Lane, Ottawa, IL 61350 • Tel: 800/252-7074, 815/434-7800 • FAX: 815/434-8176 e-mail: sales@freqdev.com • Web Address: http://www.freqdev.com Models 900CT & 900BT Model 900 Series Front Panel Description D E Single Channel – A B Certified C Location of Front Panel Terminals and Controls M L K J I H G F A. POWER Status Lamp: This red LED indicates whether or not the power to the analog filter circuitry of a Model 900CT/BT Series instrument is ON. With the power switch in the ON position, the LED glows continuously indicating internal DC power levels are correct. If LED does not light when power switch is in ON position, 1) reset instrument by cycling POWER switch OFF and ON, 2) Check line fuse. D. CORNER FREQUENCY Selector Switch (0-9): This ten position rotary switch selects the 1’s digit of the desired corner frequency between 0 and 9 in discrete increments of 1. E. MULTIPLIER Selector Switch: This fourposition rotary switch multiplies by a factor of either 0.1, 1.0, 10 or 100, the aggregate value set on the 3 CORNER FREQUENCY selector switches. (B, C & D) F. GAIN Switch: This three-position toggle switch selects an overall filter gain of 0, 10, or 20 dB. G. BYPASS Switch: OUT and IN setting of this two position toggle switch routes the input signal to the internal filter or around it, respectively. E.g. OUT position - no Bypass, the signal passes through the filter. In either case, the gain switch remains operational. H. INPUT Switch: This three position toggle configures the instrument for either differential inputs (A-B), a single-ended input (A), or input nulling ( ) which grounds both the (A) and (B) input terminals. I. & J. (A) and (B) Input Terminals: This pair of shielded, female BNC connectors accept signal inputs (A) and (B). The instrument applies a non-inverting gain to input (A) and an equal but opposite inverting gain to input (B) while the GAIN switch sets the magnitude of differential gain to 0, 10, or 20 dB. The BNC shields have been internally connected to the instrument ground. K. GROUND ( ) Terminal: This “Banana” type test jack provides neat and secure access to the internal ground. This terminal is a convenient junction for grounding external system and measurement instrumentation and/or apparatus. L. OUT Terminal: This terminal is a female BNC connector. The shield on the BNC is internally connected to the instrument ground. M. OFFSET Adjust: This adjustment is intended to zero the offset that results from the instrument’s own circuitry and does not provide for wide range offset to remove dc input signals. For 900BT models only: If LED is flashing, recharge batteries, approximately 30 minutes of operation remains. B. CORNER FREQUENCY Selector Switch (0-400Hz): This five position rotary switch selects the 100’s digit of the corner frequency designator. The switch selectable values are 0, 100, 200, 300 and 400 in five discrete steps. C. CORNER FREQUENCY Selector Switch (0-90): This ten-position rotary switch selects the 10’s digit of the desired corner frequency between 0 and 90, in discrete increments of 10. 4 1784 Chessie Lane, Ottawa, IL 61350 • Tel: 800/252-7074, 815/434-7800 • FAX: 815/434-8176 e-mail: sales@freqdev.com • Web Address: http://www.freqdev.com Models 900CT & 900BT Model 900 Series Rear Panel Description Single Channel – Certified Location of Rear Panel Terminals, Controls and Labels Model 900CT Feb. 03 SELECT FUSE NOM. FREQ. SN: 00101 115v (250v 1.0A) 60 Hz 900CT-9L8B 230v (250v 0.5A) 50 Hz MADE IN U.S.A. WAR NING: Do not remove cov ers, no user serviceable parts inside. Contact : Frequency Dev ices for service, tech@fr eqdev.com N O P Model 900BT Feb. 03 SELECT FUSE NOM. FREQ. SN: 00102 115v (250v 1.0A) 60 Hz 900BT-9L8B 230v (250v 0.5A) 50 Hz MADE IN U.S.A. WARNI NG: Do not remov e cov ers, no user serviceable parts inside. Contact : Frequency Dev ices for s ervice, tec h@fr eqdev.com N. IDENTIFICATION LABEL: This label identifies the Model number, filter type, serial number, date of manufacture, operating power limits and fuse requirements of the instrument. O. AC POWER CONNECTION: Denotes plug and fuse location. P. POWER ON/OFF Switch: Is a twoposition toggle switch on the back panel that interrupts/completes the power circuit. Q. VOLTAGE Selector Module: The power module window shows the operating voltage (115 Vac or 230 Vac). At time of shipment, the voltage window is set in the 115 Vac position. For 230 Vac operations, use a screwdriver blade to pry open the module door, remove the red fuse cartridge, turn it 180 degrees, reinsert and close the module door. The numerals 230 Vac will now show in the module window. Repeat procedure to change back to 115 Vac. Q F use h o ld e r O p tio n a l s w it c h 5 1784 Chessie Lane, Ottawa, IL 61350 • Tel: 800/252-7074, 815/434-7800 • FAX: 815/434-8176 e-mail: sales@freqdev.com • Web Address: http://www.freqdev.com Models 900CT & 900BT 8 Pole Low Pass Filters 900L8L 900L8E 900L8EY 8-Pole, 6 zero Elliptic 0.1 Hz to 49.9 kHz Appendix A Page 25 1 part in 499 within each decade -0.05 dB 0 ± 0.1 dB typ. 0 ± 0.2 dB max. -100 dB typ. fc ±2% max. ±0.5% typ. ±2% max. ±0.01%/°C typ. ±0.02%/°C max. -0.05 dB -419° 0.05 dB 3.01 dB 60.0 dB 80.0 dB 1.00 fr 1.06 fr 1.83 fr 2.00 fr Single Channel – Model Transfer Function Range fc, fr Theoretical Transfer Characteristics Tuning Resolution Passband Ripple Pass Band Voltage Gain (non-inverting) Certified 900L8B 8-Pole Butterworth 0.1 Hz to 49.9 kHz Appendix A Page 9 1 part in 499 within each decade 0.0 dB 0 ± 0.1 dB typ. 0 ± 0.2 dB max. 48 dB/Octave fc ±2% max. ±0.5% typ. ±2% max. ±0.01%/°C typ. ±0.02%/°C max. -3 dB -360° 0.12 dB 3.01 dB 60.0 dB 80.0 dB 0.80 fc 1.00 fc 2.37 fc 3.16 fc Filter Specifications 8-Pole 8-Pole, 6 zero Bessel Elliptic 0.1 Hz to 49.9 kHz Appendix A Page 4 1 part in 499 within each decade 0.0 dB 0 ± 0.1 dB typ. 0 ± 0.2 dB max. 48 dB/Octave fc ±2% max. ±0.5% typ. ±2% max. ±0.01%/°C typ. ±0.02%/°C max. -3 dB -182° 1.91 dB 3.01 dB 60.0 dB 80.0 dB 0.80 fc 1.00 fc 4.52 fc 6.07 fc 0.1 Hz to 49.9 kHz Appendix A Page 24 1 part in 499 within each decade ±0.035 dB 0 ± 0.1 dB typ. 0 ± 0.2 dB max. -80 dB typ. fc ±2% max. ±0.5% typ. ±2% max. ±0.01%/°C typ. ±0.02%/°C max. -0.035 dB -323° 0.35 dB 3.01 dB 60.0 dB 80.0 dB 1.00 fr 1.13 fr 1.67 fr 1.77 fr Stopband Attenuation Cutoff Frequency Accuracy Stability Amplitude Phase Filter Attenuation (theoretical) Total Harmonic Distortion @ 1 kHz Wide Band Noise (5 Hz – 2 MHz)