Model 900
Tunable Active
Single Channel- Certified Filter Instruments
Description
Frequency Devices' Model 900 instruments furnish
the user with a 4 or 8-pole low-pass or high-pass
instrument that has a field replaceable filter module
and is tunable by front panel controls. The controls
allow the user to select a corner frequency between
0.1Hz and 49.9kHz with a resolution of 1:499 for
each of the four selectable ranges.
The instrument exhibits an input impedance of 1
M 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 M
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) Plug-in Filter Module
2) Adjustable Frequency Control
3) Differential Input Amplifiers
4) Adjustable Gain Control Chassis: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5) Off-set Adjustment 900C Standard AC powered chassis
6) Bypass Control 900B AC powered, with battery powered option
7) BNC Connectors for Signal I/O
An optional battery powered version (900B)is avail- Available Low-Pass Models: . . . . . . . . . . . . . Page
able and is particularly well suited to applications 9L4B 4-pole, Butterworth . . . . . . . . . . . . . . . . . . 3
requiring isolation from an electrically noisy primary 9L4L 4-pole, Bessel . . . . . . . . . . . . . . . . . . . . . . 3
power source.
9L8B 8-pole Butterworth. . . . . . . . . . . . . . . . . . . 3
Compact size and manual rotary switch front panel 9L8L 8-pole, Bessel . . . . . . . . . . . . . . . . . . . . . . 3
controls make 900 instruments a popular, cost 9L8E 8-pole, elliptic, 1.77, 80 dB . . . . . . . . . . . . 4
effective, easy-to-use solution for signal 9L8EY 8-pole, elliptic, 2.00, 100 dB . . . . . . . . . . . 4
conditioning applications in the following areas: 9L8D80 8-pole, constant delay, 80 dB . . . . . . . . . . 4
Anti-aliasing Filters 9L8D10 8-pole, constant delay, 100 dB . . . . . . . . . 4
Biomedical/Biotechnology Applications
Data Recording/Playback Available High-Pass Models: . . . . . . . . . . . . . Page
Data Smoothing 9H4B 4-pole, Butterworth . . . . . . . . . . . . . . . . . . 5
EKG/EEG Signal Filtering 9H8B 8-pole, Butterworth . . . . . . . . . . . . . . . . . . 5
FDM/PCM Signal Filtering 9H8E 8-pole, elliptic, 1.77, 80 dB . . . . . . . . . . . . 5
Medical Research 9H8EY 8-pole, elliptic, 2.00, 100 dB . . . . . . . . . . . 5
Industrial Process Control
Seismic Analysis General Specifications:
Vibration Analysis Ordering information . . . . . . . . . . . . . . . . . . . . . . . 10
1
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Model 900
Tunable Active
Filter Instruments
BLOCK DIAGRAM
GAIN (dB)
INPUT
10dB
0dB
A 20dB
A-B + OUT
DIFF 8-POLE TUNABLE OUTPUT
A AMP FILTER AMP
OFFSET BYPASS
NULLED
B CORNER
FREQUENCY
TUNING TYPICAL
FRONT PANEL
TYPICAL BNC CONNECTOR
OFFSET ADJUSTMENT
FUNCTION
CORNER FREQUENCY HZ MULTIPLIER
2 5 5 10
1 3 4 6 4 6 1 100
0 4 3 7 3 7 0.1
2 8 2 8
1 9 1 9
0 0
FRONT PANEL
2
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Model 900
4 & 8-Pole
Low-Pass Filters
Model 9L4B 9L4L 9L8B 9L8L
Product Specifications
Transfer Function 4-Pole, 4-Pole, 8-Pole, 8-Pole,
Butterworth Bessel Butterworth Bessel
Range fc, 0.1 Hz to 49.9 kHz 0.1 Hz to 49.9 kHz 0.1 Hz to 49.9 kHz 0.1 Hz to 49.9 kHz
Theoretical Transfer Appendix A Appendix A Appendix A Appendix A
Characteristics Page 7 Page 2 Page 9 Page 4
Tuning Resolution 1 part in 499 1 part in 499 1 part in 499 1 part in 499
within each decade within each decade within each decade within each decade
Passband Ripple 0.0 dB 0.0 dB 0.0 dB 0.0 dB
(theoretical)
DC Voltage Gain 0 ± 0.2 dB max. 0 ± 0.2 dB max. 0 ± 0.2 dB max. 0 ± 0.2 dB max.
(non-inverting) 0 ± 0.1 dB typ. 0 ± 0.1 dB typ. 0 ± 0.1 dB typ. 0 ± 0.1 dB typ.
Stopband Attenuation 24 dB/octave 24 dB/octave 48 dB/octave 48 dB/octave
Cutoff Frequency fc ± 2% max. fc ± 2% max. fc ± 2% max. fc ± 2% max.
Accuracy ± 2% max. ± 2% max. ± 2% max. ± 2% max.
± 0.5% typ. ± 0.5% typ. ± 0.5% typ. ± 0.5% typ.
Stability ± 0.02% /°C max. ± 0.02% /°C max. ± 0.02% /°C max. ± 0.02% /°C max.
± 0.01% /°C typ. ± 0.01% /°C typ. ± 0.01% /°C typ. ± 0.01% /°C typ.
Amplitude -3dB -3dB - 3 dB - 3 dB
Phase -180° -121° -360° -182°
Filter Attenuation 0.67 dB 0.80 fc 1.86 dB 0.80 fc 0.12 dB 0.80 fc 1.91 dB 0.80 fc
(theoretical) 3.01 dB 1.00 fc 3.01 dB 1.00 fc 3.01 dB 1.00 fc 3.01 dB 1.00 fc
30.0 dB 2.37 fc 30.0 dB 3.50 fc 60.0 dB 2.37 fc 60.0 dB 4.52 fc
40.0 dB 3.16 fc 40.0 dB 4.72 fc 80.0 dB 3.16 fc 80.0 dB 6.07 fc
Total Harmonic < - 90 dB typ. < - 90 dB typ. < - 90 dB typ. < - 90 dB typ.
Distortion @ 1 kHz
Wide Band Noise 200 µVrms typ 200 µVrms typ 200 µVrms typ. 200 µVrms typ.
(5 Hz - 2 MHz)
Narrow Band Noise 50 µVrms typ. 50 µVrms typ. 50 µVrms typ. 50 µVrms typ.
(5 Hz - 100 kHz)
3
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Model 900
8-Pole
Low-Pass Filters
Model 9L8E 9L8EY 9L8D80 9L8D10
Product Specifications
Transfer Function 8-Pole, 6 zero, 8-Pole, 6 zero 8-Pole, 6 zero 8-Pole, 6 zero,
Elliptic Elliptic Constant Delay Constant Delay
Range fc, fr 0.1 Hz to 49.9 kHz 0.1 Hz to 49.9 kHz 0.1 Hz to 49.9 kHz 0.1 Hz to 49.9 kHz
Theoretical Transfer Appendix A Appendix A Appendix A Appendix A
Characteristics Page 24 Page 25 Page 21 Page 22
Tuning Resolution 1 part in 499 1 part in 499 1 part in 499 1 part in 499
within each decade within each decade within each decade within each decade
Passband Ripple ± 0.035 dB -0.05 dB 0.15 dB 0.15 dB
(theoretical)
DC Voltage Gain 0 ± 0.2 dB max. 0 ± 0.2 dB max. 0 ± 0.2 dB max. 0 ± 0.2 dB max.
(non-inverting) 0 ± 0.1 dB typ. 0 ± 0.1 dB typ. 0 ± 0.1 dB typ. 0 ± 0.1 dB typ.
Stopband Attenuation -80 dB typ. -100 dB typ. -80 dB typ. -100 dB typ.
Cutoff Frequency fr ± 2% max. fr ± 2% max. fc ± 2% max. fc ± 2% max.
Accuracy ± 2% max. ± 2% max. ± 2% max. ± 2% max.
± 0.5% typ. ± 0.5% typ. ± 0.5% typ. ± 0.5% typ.
Stability ± 0.02% /°C max. ± 0.02% /°C max. ± 0.02% /°C max. ± 0.02% /°C max.
± 0.01% /°C typ. ± 0.01% /°C typ. ± 0.01% /°C typ. ± 0.01% /°C typ.
Amplitude -0.035 dB -0.05 dB - 3 dB - 3 dB
Phase - 323° -419° -306° - 311°
Filter Attenuation 0.035 dB 1.00 fr 0.05 dB 1.00 fr 3.01 dB 1.00 fc 3.01 dB 1.00 fc
(theoretical) 3.01 dB 1.13 fr 3.01 dB 1.06 fr 60.0 dB 3.08 fc 80.0 dB 4.45 fc
60.0 dB 1.67 fr 80.0 dB 1.83 fr 80.0 dB 3.57 fc 100.0 dB 5.20 fc
80.0 dB 1.77 fr 100.0 dB 2.00 fr
Total Harmonic < - 90 dB typ. < - 88 dB typ. < - 90 dB typ. < - 88 dB typ.
Distortion @ 1 kHz
Wide Band Noise 250 µVrms typ. 250 µVrms typ. 200 µVrms typ. 200 µVrms typ.
(5 Hz - 2 MHz)
Narrow Band Noise 75 µVrms typ. 75 µVrms typ. 50 µVrms typ. 50 µVrms typ.
(5 Hz - 100 kHz)
4
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Model 900
4 & 8-Pole
High-Pass Filters
Model 9H4B 9H8B 9H8E 9H8EY
Product Specifications
Transfer Function 4-Pole 8-Pole 8-Pole, 6 zero 8-Pole, 6 zero
Butterworth Butterworth Elliptic Elliptic
Range fc, fr 0.1 Hz to 49.9 kHz 0.1 Hz to 49.9 kHz 0.1 Hz to 49.9 kHz 0.1 Hz to 49.9 kHz
Theoretical Transfer Appendix A Appendix A Appendix A Appendix A
Characteristics Page 27 Page 29 Page 37 Page 38
Tuning Resolution 1 part in 499 1 part in 499 1 part in 499 1 part in 499
within each decade within each decade within each decade within each decade
Passband Ripple 0.0 dB 0.0 dB ± 0.035 dB - 0.05 dB
(theoretical)
Voltage Gain 0 ± 0.2 dB to 100 kHz 0 ± 0.2 dB to 100 kHz 0 ± 0.2 dB to 100 kHz max. 0 ± 0.2 dB to 100 kHz max.
(non-inverting) 0 ± 0.5 dB to 120 kHz 0 ± 0.5 dB to 120 kHz 0 ± 0.5 dB to 120 kHz typ. 0 ± 0.5 dB to 120 kHz typ.
Power Bandwidth 120 kHz 120 kHz 120 kHz 120 kHz
Stopband Attenuation 24 dB/octave 48 dB/octave -80 dB typ. -100 dB typ.
Cutoff Frequency fc ± 2% max. fc ± 2% max. fr ± 2% max. fr ± 2% max.
Accuracy ± 2% max. ± 2% max. ± 2% max. ± 2% max.
± 0.5% typ. ± 0.5% typ. ± 0.5% typ. ± 0.5% typ.
Stability ± 0.02% /°C max. ± 0.02% /°C max. ± 0.01% /°C max. ± 0.02% /°C max.
± 0.01% /°C typ. ± 0.01% /°C typ. ± 0.01% /°C typ. ± 0.01% /°C typ.
Amplitude - 3 dB - 3 dB - 0.035 dB - 0.5 dB
Phase -180° -360° -323° -419°
Filter Attenuation 40 dB 0.31 fc 80 dB 0.31 fc 80 dB 0.56 fr 100 dB 0.50 fr
(theoretical) 30 dB 0.42 fc 60 dB 0.42 fc 60.0 dB 0.60 fr 80.0 dB 0.55 fr
3.01 dB 1.00 fc 3.01 dB 1.00 fc 3.01 dB 0.88 fr 3.01 dB 0.94 fr
0.02 dB 2.00 fc 0.00 dB 2.00 fc 0.03 dB 1.00 fr 0.03 dB 1.00 fr
0.00 dB 2.00 fr 0.00 dB 2.00 fr
Total Harmonic < - 88 dB typ. < - 88 dB typ. < - 88 dB typ. < - 88 dB typ.
Distortion
Wide Band Noise 400 µVrms typ. 400 µVrms typ. 400 µVrms typ. 500 µVrms typ.
(5 Hz - 2 MHz)
Narrow Band Noise 100 µVrms typ. 100 µVrms typ. 100 µVrms typ. 150 µVrms typ.
(5 Hz - 100 kHz)
5
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Model 900
Location of Front Panel
Terminals and Controls
Location of Front Panel Terminals and Controls
A B C D E F G H J
POWER CORNER FREQUENCY HZ MULTIPLIER ACTIVE FILTER
2 5 5 10
1 3 4 6 4 6 1 100
GAIN BYPASS INPUT
0 4 3 7 3 7 0.1 (DB)
ON 2 8 2 8 10 IN A-B
1 1 0 A
9 9
0 0
OFF 20 OUT
+
900 OFFSET OUT A B
K L M N O
A. POWER ON/OFF Switch: A two E. CORNER FREQUENCY Selector K. OFFSET Adjust: This adjustment is
position toggle switch that Switch (0-9): This ten position rotary intended to zero the offset that results
interrupts/completes the internal DC switch selects the 1's digit of the desired from the instruments own circuitry and
power circuit and resets the battery corner frequency between 0 and 9, in does not provide for wide range offset to
protection circuit. discrete increments of 1. remove dc input signals.
B. POWER Status Lamp: This red LED F. MULTIPLIER Selector Switch: This L. GROUND ( ) Terminal: This
indicates whether or not the power to the four position rotary switch multiplies by a "Banana" type test jack provides neat
analog filter circuitry of a Model 900 factor of either 0.1, 1, 10, or 100, the and secure access to the internal
instrument is correct. With the POWER aggregate value set on the three ground. This terminal is a convenient
switch in the ON position the LED glows CORNER FREQUENCY selector junction for grounding external system
continuously if the internal DC power switches. (C, D & E). and measurement instrumentation
levels are correct, flashes for low DC and/or apparatus.
power levels, and goes off for grossly G. GAIN Switch: This three position
improper DC power levels. See power toggle switch selects an overall filter gain M. OUT Terminal: This terminal is a
lamp status, page 14. of either 0, 10, or 20dB. female BNC connector. The shield on
the BNC is internally connected to the
C. CORNER FREQUENCY Selector H. BYPASS Switch: OUT and IN setting instrument ground.
Switch (0-400): This five position rotary of this two position toggle switch routes
switch selects the 100's digit value of the the input signal to the internal low-pass N & O. (A) and (B) Input Terminals:
corner frequency designator. The switch filter or around it, respectively. For either This pair of shielded, female BNC
selectable values are 0, 100, 200, 300, case, the GAIN switch remains connectors accept signal inputs (A) and
and 400 in five discrete steps. operational. (B). The instrument applies a non-
inverting gain to input (A) and an equal
D. CORNER FREQUENCY Selector J. INPUT Switch: This three position but opposite inverting gain to input (B)
Switch (0-90): This ten position rotary toggle configures the instrument for while the GAIN switch sets the
switch selects the 10's digit of the either differential inputs (A-B), a single- magnitude of differential gain to either 0,
desired corner frequency between 0 and ended input (A), or input nulling ( ) 10, or 20dB. The BNC shields have
90, in discrete increments of 10. which grounds both the (A) and (B) input been internally connected to the
terminals. instrument ground.
6
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Model 900
Controls
and Terminals
Location of Rear Panel Terminals and Controls
FUSE 3/16 A 250V
Q SELECT
NOM
110V
105-
220V
210-
VDC 125 250
NOM 50- 50-
P FREQ 60 HZ 60 HZ
S
MODEL No. 900_8L 110
R
220
SERIAL No. 20067
MADE IN U.S.A. 10/31/94 VOLTAGE
SELECTOR
P. IDENTIFICATION LABEL: This label R. POWER CONNECTION: Denotes of shipment, the voltage select
identifies the filter type, serial number plug and fuse location. switch is preset in the 110 Vac
and date of manufacture. position. For 220 Vac operation, this
S. VOLTAGE Selector Switch: This two switch must be rotated to the 220 Vac
Q. POWER designation: This label position switch determines the operating position.
identifies operating power limits and fuse voltage (110 Vac or 220 Vac). At time
requirements of the instrument.
POWER Lamp Status
Filter Replacement Instructions:
Steps to Follow:
POWER
SOURCE 1. Unplug (disconnect from Power)
instrument.
LAMP 2. Turn chassis over.
STATUS AC POWER LINE INTERNAL BATTERY
3. With black instrument supports
facing up, remove mounting
screws.
ON Operating Normally Operating Normally 4. Holding cover in place, turn unit to
up-right position and remove top
Line and internal voltages are correct Sufficient battery charge cover.
5. Locate black filter module and
carefully remove from channel
FLASHING Possible Causes: Possible Causes: board.
Low AC line voltage Batteries near exhaustion
6. Match replacement filter module
Fault external causing power (approximately 30 minutes of pin locations with insertion holes
overload Internal instrument fault operation remain in channel board and gently insert
replacement module.
7. Replace instrument top cover,
OFF Possible Causes: Possible Causes: carefully turn over and install in-
POWER Switch off POWER Switch off strument supports and screws.
Momentary power line drop-out Internal protection circuit
tripped protection circuit.* tripped.*
Open line fuse
*Reset by cycling POWER Switch off then on.
7
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Model 900
Operation and Application
Guide Lines
Initial Setup
Select desired operating voltage 110 Vac Set the OFFSET control for a zero-volt The C, D and E switches combined can
or 220 Vac. See note "S" page 14. reading on the scope. select base corner frequency values
ranging from 1 to 499 Hz in 1Hz steps,
Set the POWER ON/OFF Switch to ON. Subsequent changes of CORNER
with switch weighings as just described.
A continuously lit POWER status lamp FREQUENCY, GAIN or BYPASS control
denotes proper internal dc voltages, an settings will introduce a small dc output The accuracy of the corner frequency is
essential indication for battery powered offset which should be zeroed for critical improved by selecting the largest
models. Allow the instrument a three applications. possible base frequency and down
minute warm-up period to achieve scaling by the MULTIPLIER. The
Leaving all other controls unchanged,
thermal equilibrium. greatest accuracy is obtained with the
set the Input Switch to (A-B) and apply a
largest base 400, and the 0.1X
To perform initial adjustment and/or 5Vdc signal simultaneously to input
MULTIPLIER switch 400 setting.
operational testing, set the remaining BNCs (A) and (B). The voltage
front panel controls as follows: measured at the OUT BNC should be Relative accuracy of selected 40 Hz
5-5=OVdc. This completes preliminary actual corner frequency for different
a) The three base CORNER
test and adjustment. multiplier switch settings.
FREQUENCY switches and the
MULTIPLIER to the desired corner
frequency... BASE FREQ X MULT. RELATIVE
Corner Frequency Selection
msd Isd TUNING
b) The OFFSET control to approximately
To select a corner frequency, simply set C D E F ACCURACY
mid-range...
the three CORNER FREQUENCY
c) The GAIN switch to the desired value... switches and the MULTIPLIER switch for 4 0 0 0.1X GREATEST
the desired numerical value. 0 4 0 1X LESS
d) The BYPASS switch to OUT... 0 0 4 10X LEAST
The CORNER FREQUENCY switch
e) The INPUT switch to ground ( )...
weighings follow standard decimal
Connect a dc-coupled oscilloscope, of positional convention. The instrument utilizes a differential input
vertical sensitivity 10mV/CM or better, or amplifier to reject prevalent forms of
a digital voltmeter (DVM) to the electrical interference, while presenting
instrument front panel BNC connector desirable input characteristics to the sig-
labeled OUT. nal source requiring filtering.
Circuit model illustrating relationship between filter's differential input The differential Input
amplifier and external signal and error sources.
The differential input configuration is
DIFFERENTIAL ideal for measuring the difference
INPUT AMPLIFIER
0d
between two values rather than the
B
INPUT SIGNAL AND 10
values themselves. Bridge circuits
NOISE VOLTAGE SOURCES dB
utilizing strain gages, thermocouples and
RSA
*
A 20
dB
a variety of other types of transducers
(+) *
GAIN = K
generate differential full scale output
VA
RCM+ +
*
OUT voltages in the order of millivolts that are
VCM
RD DIFF FILTER/ OUTPUT often superimposed upon volt-level
AMP BYPASS AMPLIFER
VB RCM-
- reference and noise values.
SIGNAL
COMMON
()
The importance of CMRR
RSB
B Vo = K(VA - VB) + Vcm/CMRR : WHERE
K = 1, 10 AND 10 FOR GAIN SETTINGS In actual system environments, each
* Vs COM +Vs
OF 0, 10 AND 20dB RESPECTIVELY.
SEE TEXT FOR REMAINING TERMS.
signal and power return conductor can
COUPLED generate an interference voltage
POWER LINE
NOISE VOLTAGE () (+) * DENOTES FRONT PANEL ACCESS
proportional to the net conductor
AC POWER SUPPLY resistance and the electrical current
OR
VP
INTERNAL BATTERIES
level. Any such interference voltages
appear as common mode signals to the
SIGNAL
amplifier, and are rejected as such.
COMMON
8
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Model 900
Specifications
(@25°C and rated Power Input)
Input Characteristics Common Mode Rejection Ratio vs.
Input Impedance: Frequency
Differential 2 M Shunted by 47pF 20
Single Ended 1 M Shunted by 47pF 30
Input Voltage:
40
Linear Differential* 20V p-p (Gain Set at 0 dB)
Vin = 20Vp-p
Max Safe Differential Any Continuous Value between +/-100V
CMRR dB
50 Vout
CMRR = 20 log
Max Safe Common Mode Any Continuous Value between +/-100V Vin FILTER
60 A in
Bias Current 175pA max.; 30pA typ. B in
Common Mode Rejection Ratio with 70 Vout
Vin
2k Source Unbalance and 0 dB Gain > 60dB, dc to 50kHz
80
Output Characteristics 1K 10K 100K 1M 10M
Full Power Bandwidth** dc to 600kHz FREQUENCY HZ
Maximum Output Voltage 10V p-p for RL = 50 Output Voltage Swing vs. Load
20V p-p for RL = 2k Resistance
35 70
Short Circuit Output Current +/-100 mA continuous
30 60
Output Protection +/-200 mA without damage OUTPUT VOLTAGE SWING
vs.
Short Circuit to Ground Only
LOAD CURRENT mA
25 LOAD RESISTANCE 50
Output Impedance 50
VOLTS p-p
20 RMS 40
Offset Voltage Adjustable to Zero at Front Panel LOAD
CURRENT
(Range +/-500mV dc) 15 30
10 20
Power Supply
AC Line Operation: 5 10
Power 20 Watts max.
Voltage Frequency Range-Rear Panel: 10 100 1K 10K 100k
LOAD
110 V 105 to 125Vac @ 50/60Hz
220 V 210 to 250Vac @ 50Hz Voltage Noise vs. Frequency
Fuse 3/16 Amp 80 1x10
-4
90
Battery Operation (Optional) AC LINE OPERATED
(0dBV = 1VRMS)
-5
Time for full Charge 14 to 16 Hrs. @ 20 °C 100 1x10
Battery Life Approx. 500 Charge-Discharge Cycles
HZ
110
Battery Charger Automatic Uninterruptible
BATTERY -6
V/
HZ
Charge Status Indicator-Front Panel 3 Status Levels 120 OPERATION 1x10
NO SHIELDING
Battery Operation 9 hours typ. (See graph)
dBV/
130
fc
-7
1x10
Temperature 140
BATTERY OPERATION
Operating Temperature: SHIELDED ENCLOSURE
10 100 1K 10K 100K
With Batteries +5 °C to +50 °C FREQUENCY HZ
AC Line 0 °C to +50 °C
Storage Temperature -25 °C to +70 °C Battery Life vs. Load Resistance
14
Mechanical 12
Vin = 1KHZ Sine - fc >>f in
Dimensions 3.5"H x 8.5"W x 9.3"D FILTER
INPUT
TA = 20 °C
10
8.89cmH x 21.59cmW x 23.62cmD VOLTAGE
TIME (HRS)
Weight with Battery 4.5 lbs; 2.04 kgs. 8
1Vp-p
without Battery 3.5 lbs; 1.59 kgs 6
10Vp-p
Case Material ABS plastic NOTE:
4 THE TIME SCALE IS PLOTTED
Color PC Bone 20Vp-p FROM THE TIME WHEN THE
POWER INDICATOR FLASHES.
2 THE FILTER CAN BE OPERATED
* Signal plus common mode voltage cannot exceed 20V peak for a linear output. ABOUT ANOTHER 30 MIN. AT
REDUCED SIGNAL.
** Output characteristics of input amp with filter by-passed. 0
10 100 1K 10K 100k
LOAD
9
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Model 900
Specification Pin-Out and Package Data
(25°C and Vs ± 15 Vdc) Ordering Information
Model 900 INSTRUMENT ORDERING GUIDE
A. CHASSIS 1
1. 900C Standard AC powered chassis 1
2. 900B AC powered, with battery powered option
2,4
FILTER TRANSFER FUNCTIONS AVAILABLE
B. LOW-PASS
BUTTERWORTH
1. 9L4B 4-pole Butterworth
2. 9L8B 8-pole Butterworth
BESSEL
3. 9L4L 4-pole Bessel
4. 9L8L 8-pole Bessel
ELLIPTIC
5. 9L8E 8-pole elliptic, 1.77, 80dB
6. 9L8EY 8-pole elliptic, 2.00, 100dB
CONSTANT DELAY
7. 9L8D80 8-pole constant delay, 80dB
8. 9L8D10 8-pole constant delay, 100dB
C. HIGH-PASS
BUTTERWORTH
1. 9H4B 4-pole Butterworth
2. 9H8B 8-pole Butterworth
ELLIPTIC
3. 9H8E 8-pole elliptic, 1.77, 80dB
4. 9H8EY 8-pole elliptic, 2.00, 100dB
To order, simply specify the chassis style and filter model number that incorporates the desired
features.
Filter Type
Ordering Information 3
Transfer Function
L - Low-Pass B - Butterworth
H - High-Pass L - Bessel
D80 - constant delay (-80dB)
900C/9L8L D10 - constant delay (-100dB)
1 E - elliptic 1.77 (-80dB)
Chassis Style
EY - elliptic 2.00 (-100dB)
C - Standard AC Power
B - AC Powered, with Battery Power Option No. of Poles
4
8
NOTE:
1. See page 14, Item S - Voltage Select Switch: At time of shipment, voltage select switch is preset in the 110 Vac position.
For 220 Vac operation, this switch must be rotated to the 220 Vac position.
2. Individual filter modules can be purchased for field replacement.
3. All models tunable from 0.1 Hz to 49.9 kHz.
4. See page 8 for Filter Replacement Instructions.
We hope the information given here will be helpful. The information is based on data and our best knowledge, and we consider the information to be true and accurate. Please read all statements,
recommendations or suggestions herein in conjunction with our conditions of sale which apply to all goods supplied by us. We assume no responsibility for the use of these statements,
recommendations or suggestions, nor do we intend them as a recommendation for any use which would infringe any patent or copyright. IN-00900-00
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CompuMess Elektronik GmbH · Lise-Meitner-Str.1 · 85716 Unterschleissheim
Tel 089-321501-0 · Fax 089-321501-11 · www.compumess.de · www.netzteile.de