TB 9-6625-2331-24
IDENTIFICATION AND DESCRIPTION
1. Test Instrument Identification.
This bulletin provides instructions for the
calibration of Electronic Counter, Fluke, Model PM6681/656. 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. None.
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. Forms, records and reports required for calibration
personnel at all levels are prescribed by TB 750-25.
3. Calibration Description. TI parameters and performance applications which pertain
to this calibration are in table 1.
Table 1. Calibration Description.
Test instrument parameters
Performance specifications
Time base
Frequency: 10 MHz
Aging rate (after 48 hour warm-up): < 5 x 10-10 per day
Aging rate (after 24 hour warm-up): < 1 x 10-8 per month
Aging rate (after 24 hour warm-up): < 7.5 x 10-8 per year
Line voltage variation (for 10% variation): <5 x 10-10
Total uncertainty @ 2σ: <1 x 10-7 per year
Channel A and B sensitivity
20 mV rms (-21 dBm), <100 MHz
30 mV rms (-17 dBm), 100 to 200 MHz
40 mV rms (-15 dBm), 200 to 250 MHz
60 mV rms (-11 dBm), >250 MHz
Channel C sensitivity
20 mV rms (-21 dBm), 150 to 300 MHz
10 mV rms (-27 dBm), 300 to 2500 MHz
20 mV rms (-21 dBm), 2500 to 2700 MHz
Volt max/min
Range:
-50 to +50 V dc
100 mV to 100 V pp (1 Hz to 100 MHz)
Accuracy:
5 V dc (1X)
(1% + 4 mV)
50 V dc (10X)
(2% + 40 mV)
5 V pp (1X)
<30 MHz
(6% + 4 mV)
5 V pp (1X)
>30 MHz
(25% + 4 mV)
50 V pp (10X)
(10% + 40 mV)
Trig level outputs
(5% of output level + 30 mV)
