DESCRIPTION
The Model 31A
Series high-pass, elliptical filter/voltage gain amplifier is one of many
plug-in filter cards used in the Models 3905B/3905C/3916B/3916C Programmable
Filter Systems chassis.
FILTER FEATURES
As
an elliptical filter, the Model 31A Series has a tunable cutoff frequency
range from 0.01Hz to 99kHz, a rolloff rate of 115dB/octave and a minimum
stopband attenuation of >80dB. Passband ripple is typically 0.22dB.
The 31A provides
either a single-ended or differential input with a common mode rejection
of >60dB. Input gains up to 40dB in 10dB steps and output gains to 20dB
are also provided. The 31A will accept input signals of ±10V peak at 0dB
gain and has selectable ac or dc coupling. Overload detectors are standard
and assist the user in detecting excessive input signals or incorrect
gain settings.
AMPLIFIER FEATURES
The 31A is also
a programmable voltage gain amplifier for applications that require a
low noise amplifier. The amplifier has a bandwidth of 1MHz and gains to
60dB, selectable in 10dB steps, and a wideband noise of <20µV.
APPLICATIONS
Typical
applications for the Model 31A are: removing line related frequencies,
enhancing signal-to-noise ratio, distortion testing, low noise pre-amplification
and many more. Plug-in cards offering other types of filters with different
frequency ranges, slopes and number of channels are also available.
SPECIFICATIONS
FUNCTION:
High-pass filter;
voltage gain amplifier.
FILTER MODE
Type: 7-pole, 6-zero elliptical.
Attenuation: 115dB/octave.
Passband Ripple: 0.22dB typical, 0.4dB max.
Tunable Frequency Range fc:
Model 31A-1: 1Hz to 99kHz.
Model 31A-2: 0.1Hz to 9.9kHz.
Model 31A-3: 0.01Hz to 990Hz.
Frequency Response:
|
Band
|
Model
|
Cutoff Frequency
Range
(Hz)
|
Resolution
(Hz)
|
|
1
|
31A-1
|
1-99
|
1
|
|
31A-2
|
0.1-9.9
|
0.1
|
|
31A-3
|
0.01-0.99
|
0.01
|
|
2
|
31A-1
|
100-990
|
10
|
|
31A-2
|
10-99
|
1
|
|
31A-3
|
1.0-9.9
|
0.1
|
|
3
|
31A-1
|
1k-9.9k
|
100
|
|
31A-2
|
100-990
|
10
|
|
31A-3
|
10-99
|
1
|
|
4
|
31A-1
|
10k-99k
|
1k
|
|
31A-2
|
1k-9.9k
|
100
|
|
31A-3
|
100-990
|
10
|
Relative Gain at fc:
–0.22dB at 0.99fc nominal.
Cutoff Frequency Accuracy: ±2%.
Bandwidth:
Model 31A-1: dc coupled, fc to upper 3dB cutoff, >500kHz
at 1Vrms with 0dB gain.
Model 31A-2 and 31A-3: dc coupled, fc to upper 3dB cutoff,
>100kHz at 1Vrms with 0dB gain;
ac coupled, 0.32Hz to fc.
Stopband Attenuation: >80dB.
Stopband Frequency (fs): 0.59fc.
Insertion Loss: 0dB ±0.1dB.
Pre-Filter Gain: 0dB, 10dB, 20dB, 30dB, 40dB ±0.1dB.
Post-Filter Gain: 0dB, 10dB, 20dB ±0.1dB.
Input Coupling: ac or dc.
Wideband Noise (RTI with 2MHz BW Detector): min. gain, 1kHz cutoff
<400µV, Max fc cutoff, <1mV; Max. gain, <20µV.
Harmonic Distortion: –80dB at 1kHz.
Spurious Components: –80dB below full scale with input source <50
ohms.
DC Stability: Typically ±10µV/°C.
Crosstalk Between Channels: –85dB below full scale with input source
<50 ohms.
AMPLIFIER MODE
Bandwidth: dc coupled, dc to >1MHz
min. gain, >400kHz max. gain; ac coupled,
0.32Hz to >1MHz.
Insertion Loss: 0dB ±0.05dB.
Gain: 10dB to 60dB in 10dB steps ±0.1dB.
Input: Differential or single-ended +(in phase), –(inverted).
CMRR: >60dB to 10kHz; approximately 50dB at 100kHz.
Sensitivity: 10mV peak with 60dB total gain for 10V peak output.
Maximum Input: ±10V peak at 0dB gain reduced in proportion to gain
setting.
Impedance: 1M ohm in parallel with 100pf.
Coupling: ac or dc.
Maximum DC Component: ±100V in ac coupled mode.
Output:
Maximum Voltage (o.c.): 7Vrms to 200kHz; 3Vrms to 500kHz; 1Vrms
to 1MHz.
Impedance: 50 ohms.
DC Offset: Adjustable to zero volts.
Harmonic Distortion (1V output): <–80dB (0.01%) to 10kHz; <–60dB (0.1%)
to 100kHz..
Wideband Noise (referred to input, 2MHz BW detector): 100µV min. gain;
20µV max. gain.
DC Stability (RTI): Typically ±10µV/° C.
GENERAL
Phase Match Between Channels:
1° typical, 2° max from 1.3fc to 10fc; 2° typical,
4° max from fc to 1.3fc. For like Models in same
chassis, otherwise consult factory.
Amplitude Match Between Channels: ±0.1dB typical, ±0.2dB max from
fc to 1.3fc; 0.1dB max from 1.3fc to
10kHz, 0.2dB max to 100kHz.
Crosstalk Between Channels: >85dB below full scale with input source
<50 ohms.
Switch: For selection of Input, +(in phase), Differential or –(inverted).
Input/Output Connectors: BNC.
Power Requirements: 15 watts.
Weights: 1.75 lbs (.8kg).
Accessories: Operating manual.
OPTIONS
Extended 1
Year Warranty: Part No. EW31A-1, EW31A-2, EW31A-3.
Specifications
apply at 25°C ±5°C.
Specifications subject to change without notice.
NOTE:
Model 31A Series plug-in filter/amplifier cards must be
used with 3905B/3905C or
3916B/3916C chassis.
Copyright ©
March 01, 2006 Krohn-Hite
Corporation. All rights reserved.
15 Jonathan Drive, Unit 4, Brockton, MA 02301-5566 U.S.A.
Tel: (508) 580-1660; Fax: (508) 583-8989; info@krohn-hite.com
