Hilberling PT-8000A, Operating Manual

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PT-8000A Operating Manual v2.00.33
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13 N
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13.1 Notch Filter: IF-Notch and DSP Multi Notch
Two notch filters of different type are available in the PT-8000A.
One is working at 1
st
IF @ 40.7 MHz – it´s the classical type of manual notch
filtering using a Xtal bridge – the IF-NOTCH.
The other one is part of the DSP – it´s an Automatic Multi-Notch Filter
(ANF/MNF) – here called the DSP NOTCH.
IF-NOTCH and DSP-NOTCH may be engaged simultaneously.
Notch filtering is not available in AM and FM. In case NOTCH filtering is
active and modes are changed to AM/FM both NOTCHs will cease operation.
After power on both NOTCH filters are off.
13.1.1 IF-NOTCH Filter
The IF-NOTCH will
be activated by
pushing the control
IF-NOTCH which is
located as depicted:

On the display it is outlined as NOTCH 2.
Turning IF-NOTCH will adjust the variable notch through the passband hence
the interference will be almost nullified.
13.1.2 DSP Multi NOTCH Filter
(„digital“ MNF)
Pushing the NOTCH button located in
the cluster DSP will activate the
automatic multi-notch filtering
(ANF/MNF):

On the display the DSP NOTCH is outlined as NOTCH 1.

DSP NOTCH-LED will be on.
The DSP will now detect even multiple interferences and will cancel them
effectively.
Fig. 60
Fig. 61
Fig. 63
Fig. 62