5-4
5
FUNCTIONS FOR RECEIVE
The Twin PBT (Passband Tuning) function electroni-
cally narrows the IF passband width by shifting the IF
frequency slightly outside of the IF filter passband to
reject interference. This transceiver uses the DSP cir-
cuit for the PBT function.
By rotating both
[TWIN PBT] controls (inner/outer;
PBT1 and PBT2) with the same position, PBT func-
tions as an IF shift control.
The limit of the variable range depends on the pass-
band width and mode. The limit of the variable range
is half of the passband width, and PBT is adjustable in
200 Hz (AM) or 50 Hz (other models) steps.
PBT OPERATION EXAMPLE
IF center frequency
Interference Desired signal
Passband
Both controls at
center position
Cutting the lower
passband
Cutting both higher and
lower passbands
Interference
Interference
Desired signal
Passband
TWIN PBT
TWIN PBT
TWIN PBT
• The
[TWIN PBT] controls should normally be set
to the center positions (PBT shift is zero) when
there is no interference.
• When PBT is used, the audio tone may change.
• While rotating the
[TWIN PBT] controls, noise may
occur. This comes from the DSP unit and does not
indicate an equipment malfunction.
[TWIN PBT]
■
Adjusting the Twin PBT operation
Previous view
