Audio Peak Filter - Kenwood TS-890S In-Depth Manual

07 DSP
● AM and FM Modes
In the AM mode, the AF filter is placed after demodulation.
It adopts a mechanism that switches the IF filter bandwidth when the high-cut frequency is switched. Meanwhile,
switching the low-cut frequency alters only the AF filter setting. In the AM mode, extending the bandwidth only with the
IF filter may cause the audio to sound distorted. Combining the use of the AF filter in this case allows the audio to stand
out.
In the FM mode, it is possible to configure the low-cut or high-cut frequency of the AF filter for the audio after
demodulation without affecting the IF filter setting. When the CTCSS feature is turned on, the high-pass filter is inserted
in addition to the low-cut frequency filter to prevent the sub-tone signals from standing out.
As with the SSB and CW modes, it is also possible to select "Narrow", "Medium" or "Wide" on the RX Filter screen in the
AM and FM modes.

Audio Peak Filter

The audio peak filter is applicable in the CW and FSK modes.
In the CW mode, it is a peak filter with the pitch frequency as the center frequency which helps to enhance the
intelligibility by highlighting the desired signal when it lacks intelligibility due to noise.
The passband width can be configured to one of the three levels ("Narrow", "Medium" and "Wide") to provide a
maximum peak gain of +6 dB. The peak frequency can be shifted within the range of ±200 Hz with respect to the pitch
frequency.
Frequency (Hz)
Fig. 45 CW Audio Peak Filter Characteristics (Medium)
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