Section IV TUNING A MULTICAVITY KLYSTRON
1-53.
TUNING METHODS
1-54.
SYNCHRONOUS TUNING PROCEDURE
a. There are two methods of tuning a
a. Figure 57 shows a typical four-cavity
multicavity klystron -- synchronous tuning or
klystron amplifier front panel control. The front
stagger tuning. The method used depends on
panel controls are the kinds that you'll use when
whether maximum gain or broad bandwidth is
tuning a multicavity klystron.
desired. Synchronous tuning provides the highest
gain and stagger tuning provides the broadest
b. A general procedure for synchronous
bandwidth. So when you can use narrow band
tuning is as follows.
transmission, synchronous tuning may be used for
maximum gain. However, to handle multichannel
(1) Adjust all tuning cavities to the
communications, the stagger tuning method must be
highest possible frequency.
used to pass the broad band of frequencies involved.
(2) Adjust the RF drive power input to
b. Stagger tuning does not mean that you
the value specified for the klystron.
have to operate with low power. With stagger
tuning the klystron is capable of producing the
(3) Tune the input cavity for minimum
required power output by having its input power
reflected power.
Minimum reflected power
increased or by operating at saturation.
indicates that the input cavity is tuned to drive
frequency and is absorbing most of the input.
Reflected power is sometimes referred to as back
power or return power. All three names have the
same meaning.
Figure 57. Typical front panel controls for tuning multicavity klystron.
344 L1
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