TB 9-4931-413-40
IDENTIFICATION AND DESCRIPTION
1. Test Instrument Identification.
This bulletin provides instructions for the
calibration of Sound-Level Meter, General Radio Models 1551-C and 1565-A. The
manufacturer's instruction 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 2
hours, using the physical 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 in table 1.
Table 1. Calibration Description
Test instrument parameters
Performance specifications
Sound-level range
Model 1551-C: 24 to 150 db above 0.0002 P bar at 1000 Hz
Model 1565-A: 44 to 144 db above 0.0002 Pbar at 1000 Hz
Model 1565-B: 40 to 140 db above 0.0002 Pbar at 1000 Hz
Model 1982: 30 to 130 db above 0.0002 Pbar at 1000 Hz
EQUIPMENT REQUIREMENTS
calibration procedure. This equipment is issued with Secondary Reference Calibration
Standards Set, NSN 4931-00-621-7878. 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
between the standard and TI. Where the four-to-one ratio cannot be met, the actual
accuracy of the equipment selected is shown in parenthesis.
5. Accessories Required. The accessories required for this calibration are common
usage accessories, issued as indicated in paragraph 4 above, and are not listed in this
calibration procedure.