Sample Rate, Measurement Time, And Reset; Am Characteristics; Fm Characteristics - HP 5340A Operating And Service Manual

Model 5340A
Operation

3-11. Sample Rate, Measurement Time, and Reset

3-12. The sample rate control sets the interval between measurements, but not the interval of the
measurement. On the 5340A, the minimum sample rate is variable between approximately 50
milliseconds and 5 seconds. For 1 Hz RESOLUTION settings, a n additional 1 sec delay is incurred.
A hold feature can be selected to "freeze" a measurement display indefinitely.
3-13. The measurement interval (gate time) is the time that the counter's gate remains open to
accumulate counts. In the 5340A, the gate time is
input frequency. Typical measurement time for a n 18 GHz signal with 1K resolution selected is
about 120 msec. With 1 Hz resolution selected and a n 18 GHz input, the gate time is quite long,
approximately 120 seconds. However during this time, the LOCK annunciator lights to indicate
that a measurement is in progress.
3-14. Reset is accomplished by pressing the RESET switch or changing the RESOLUTION or
RANGE switch. When the counter is reset, the display reads all zeros and a h e w measurement
cycle is initiated.

3-15. AM Characteristics

3-16. The 5340A will measure inputs containing amplitude modulation provided that the mini-
mum level of the input signal is greater than the sensitivity specification. The maximum modu-
lation permissible can be calculated by the following formula:
= % modulation
v u
As a n example of the use of the formula, calculate the maximum permissible modulation for
a -10 dBm (70 mV) input at 10 GHz. At 10 GHz, the sensitivity specification is -35 dBm (4 mV)
Using the formula:
V u - V s 7 0 m V - 4 m V
v u

3-17. FM Characteristics

3-18. The 5340A will measure carrier frequencies in the presence of frequency modulation,
phase modulation, or residual noise.
rate and carrier frequency as shown in Figure 3-1.
3-2
where: Vu is the unmodulated rms input level.
Vs is the sensitivity specification at the frequency
of interest.
-
70 mV
The FM characteristics are a function of the modulation
Figure 3-1. FM Characteristics
I I I
10
100
-
MODULATING FREOUENCY
a
function of the resolution selected and the
I
1 O O K
\