artisan 8640B - Frequency Stability Vs Load, Level, and Mode Test

Model 8640B TM 9-4935-601-14-7&P
PERFORMANCE TESTS
4-15. FREQUENCY STABILITY VS LINE VOLTAGE TEST (Cont'd)
PROCEDURE:
1. Connect equipment as shown in Figure 4-3 after setting Signal Generator's controls as follows:
COUNTER MODE: EXPAND...................................................................................Off
LOCK........................................................................................Off
Source ..................................................................................... INT
AM............................................................................................................................................................OFF
FM............................................................................................................................................................OFF
RANGE . ......................................................................................................................................32 - 64 MHz
FREQUENCY TUNE ...........................................................................................................................50 MHz
RF ON/OFF................................................................................................................................................ON
2. Set variable voltage transformer 5% above the nominal voltage set on generator's line power module (e.g., if
nominal line voltage is 120 Vac, set transformer for 126 Vac). Note frequency counter reading.
3. Set variable voltage transformer 10% below nominal line voltage (e.g., for a nominal 120 Vac, set transformer for
108 Vac), then note counter's reading. The frequency change from the reading noted in step 2 should be <50 Hz
(i.e., <1 ppm).
___________________________ 50 Hz
4-16. FREQUENCY STABILITY VS LOAD, LEVEL, AND MODE TEST
SPECIFICATION:
Stability vs Load (with any passive load change): <1 ppm (normal mode).
Stability vs Level Change (10 dB on OUTPUT LEVEL vernier): <1 ppm (normal mode).
Stability vs Modulation Mode Change (CW to FM): <1% of selected peak deviation or <200 Hz, whichever is greater.
NOTE
Stability specifications for phase lock mode are determined by counter time base reference. See
the internal reference tests.
DESCRIPTION:
A frequency counter is used to measure frequency shift as the output is changed from an open circuit to a short circuit, as
RF OUTPUT LEVEL is changed 10 dB, and as modulation mode is changed from CW to FM. The frequency is
monitored at the rear panel auxiliary RF output jack.
4-9
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