TB 9-6625-2151-24
IDENTIFICATION AND DESCRIPTION
1. Test Instrument Identification.
This bulletin provides instructions for the
calibration of Transmission Impairment Test Set AN/USM-485 and Hewlett-Packard,
Model 4935A with Options 001, 002, and 003. 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. Option 001 adds rechargeable battery pack. Option 002 adds
peak/average ratio measurement. Option 003 adds both 001 and 002.
b. Time and Technique. The time required for this calibration is approximately 2
hours, using the dc and low frequency technique.
2. Forms, Records, and Reports
a. Forms, records, and reports required for calibration personnel at all levels are
prescribed by TB 750-25.
b. Adjustments to be reported are designated (R) at the end of the sentence in which
they appear. When adjustments are in tables, the (R) follows the designated adjustment.
Report only those adjustments made and designated with (R).
3. Calibration Description. TI parameters and performance specifications which
pertain to this calibration are listed table 1.
Table 1. Calibration Description
Test instrument
Performance specifications1
parameters
Receiver:
Range:
20 Hz to 110 kHz
Accuracy: 20 to 9,999 Hz .......... 0.5 Hz
10 kHz to 110 kHz ... 5.0 Hz
Level (input)
Range: -40 dBm to +13 dBm
Accuracy:
20 to 50 Hz .......... 1.0 dBm
50 to 200 Hz ........ 0.5 dBm
0.2 to 15 kHz ....... 0.2 dBm
15 to 85 kHz......... 0.5 dBm
85 to 110 kHz...... N/A
to +13 dBm........ 0.1 dBm at 1004 Hz)
(-20
See footnotes at end of table.
