HP 5328A User Manual

Model 5328A
Operation
3-8.
TIME BASE OSCILLATOR
- is that element of the counter from which the time t of
Equation (1) is derived. From Equation (1)
it may be seen that the accuracy with which t is
determined has a significant effect on the measurement accuracy of the frequency f.
Consequently the 5328A employs a 10 MHz precision crystal oscillator as the time base element.
3-9.
DECADE DIVIDERS
- takes the time base oscillator signal as the input and provide as an
output a pulse train whose frequency
is variable in decade steps. The operator can control this
frequency with the FREQ RESOLUTION, N switch. The time tof Equation (1) isdetermined by the
period of this pulse train.
3-10. MAIN GATE
- is the heart of the counter. When this gate is opened, pulses from the
amplifier/trigger are allowed to pass through. The opening and closing of the main gate
is
controlled by the decade divider output to the main gate flip-flop.
3-11.
DECADE COUNTING ASSEMBLIES
- totalizes the output pulsesfrom the main gate and
displays this total after the gate is closed.
If, for example, the gate is open for precisely I-second,
the decade counting assemblies (DCA's) display the frequency, in Hertz, of the input signal.
3-12. Other basic measurements the counter can perform are described in the following
paragraphs.
3-13. Period
3-14.
Period, the inverse of frequency, can be measured by the counter by reversing the inputs
to the main gate. Now the input signal controls the duration over which the main gate
is open and
the decade divider output is counted by the DCA's. The duration of the count is, of course, one
cycle or period of the input signal (see Figure 3-2).
3-15. Unused decades in the decade divider chain can be used to divide the amplifier/trigger
output so that the gate remains open for decade steps of the input period rather than a single
period. This
is the basis for multiple period averaging. Period and period averaging techniques
are used to increase measurement accuracy on low frequency measurements as explained further
in paragraph 4-9.
NOTE
The roles of the amplifer/trigger and decade divider
outputs are reversed in measuring the period. This
same configuration also serves for ratio measurements
with the second input replacing the time base
oscillator.
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HP 5328A Specifications

General

Brand	HP
Model	5328A
Category	Cash Counter
Language	English