TB 9-6625-2287-35
IDENTIFICATION AND DESCRIPTION
1. Test Instrument
Identification.
This bulletin provides instructions for the
calibration of Electronic Voltmeters, AN/URM-145 (ME-247/U) and AN/URM-145A (ME-
247A/U) (Boonton, Model 91CA). The manufacturer's manual, TM 11-6625-524-15-1
and TM 11-6625-524-14 were used as the prime data sources 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 indicated in text.
b. Time and Technique. The time required for this calibration is approximately 4
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
parameter and
performance specifications which pertain
to this calibration are listed in table 1.
Test instrument
Performance specifications1
parameters
Voltage
Range
ranges
accuracy
(V)
(FS)
.003 to 3
10%
20
to
50 kHz
AN/URM-145 (ME-247/U)
50 kHz to
400 MHz
5%
AN/URM-145A (ME-247A/U)
.003 to 3
10 kHz to
200 MHz
5%
(Boonton, Model 91CA)
200
to
400 MHz
10%
1Verified
to 100 MHz for all systems codes except COO; for COO, verify to 400 MHz.
EQUIPMENT REQUIREMENTS
4. Equipment
Required. Table 2 identifies the
specific equipment to be
used in this
calibration procedure. This equipment is issued with Secondary Transfer Calibration
Standards Set AN/GSM-287 or AN/GSM-705. 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 listed in table 2. The accuracies listed in table 2 provide a four-
to-one ratio between the standard and TI.