TB 9-5915-214-35
IDENTIFICATION AND DESCRIPTION
This bulletin provides instructions for the
calibration of Tunable Active Filter, KrohnHite, Model 3940. The manufacturer's manual
was used as the prime data source in compiling these instructions. The equipment being
calibrated will be referred to as the TI (test instrument) throughout this bulletin.
a. Model Variations. Variations, among models, are described in text.
b. Time and Technique. The time required for this calibration is approximately 4
hours, using the dc and low frequency technique.
personnel at all levels are prescribed by TB 75025.
pertain to this calibration are listed in table 1.
Test instrument parameters
Performance specifications
Frequency range
20 Hz to 2 MHz
2%, 20 Hz to 500 kHz; 5%, 500 kHz to 2 MHz
Cutoff frequency accuracy
Butterworth, -3 db; Bessel, -7.58 db; 2%
Relative Gain
Rate of attenuation
24 dB per octave
.5 dB, 0 to 2 MHz
Insertion loss
Less than 200 V with a detector bandwidth of 2 MHz
Noise
Maximum attenuation
Greater than 80 dB
0 V, 1 mV; -15 V to +1 V, .05 V
Power supply
EQUIPMENT REQUIREMENTS
calibration procedure. This equipment is issued with Secondary Transfer Calibration
Standards Set AN/GSM286. Alternate items may be used by the calibrating activity. The
items selected must be verified to perform satisfactorily prior to use and must bear evidence
of current calibration. The equipment must meet or exceed the minimum use specifications
standard and TI. Where the four-to-one ratio cannot be met, the actual accuracy of the
equipment selected is shown in parenthesis.
usage accessories issued as indicated in paragraph 4 above and are not listed in this
calibration procedure. The following peculiar accessories are required for this calibration:
two 50 Ω feedthrough terminations, BNC plug to BNC jack, Hewlett-Packard Model
11048C (11048C), and the TI accessories 6 kHz high-pass and 2 MHz low-pass filters.
