LESSON 4.
MODEL 5257A TRANSFER OSCILLATOR
ACCP Subcourse MM0462
Model
5345A
Frequency
Time
Measurement System
LESSON OBJECTIVE
Given supportive text and diagrams:
1.
Explain/demonstrate
operation
of the 5257A.
2.
Explain purpose of each front
panel control/connector/indicator.
3.
Calculate "N" factor.
4.
Trace signal flow.
5.
Explain circuit operation.
6.
Correctly answer all exercise
questions.
CREDIT HOURS
Three
TEXT
1.
DESCRIPTION
a. General.
The Model 5257A Transfer Oscillator plug-in (figure 1)
extends to 18 GHz the frequency measuring capability of the Model 5345A
Electronic Counter. It features simple one-dial tuning, direct readout of
input frequency, and a front panel meter for zero beat detection. Both CW
and pulsed RF signals can be quickly and easily measured with this unit.
For CW signals, an automatic phase control (APC) circuit securely locks the
internal variable frequency oscillator (VFO) to the input frequency which
aids tuning and allows measurement of noisy, frequency modulated, and
rapidly drifting signals. A lock detector for CW signals causes the counter
to display all zeros until the oscillator is properly tuned to phase lock.
The Model 5257A has a frequency range from 50 MHz to 18 GHz and has the
advantage of measuring a specific frequency while rejecting sidebands and
spurious signals.
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