HT98R068 Two-way Radio MCU
Compandor Enable Flow:
Flow description:
<82C40>
：
Setup data: 40h. 2Ch[6] = 1 enables the Compandor.
Audio -- Pre-emphasis \ De-emphasis Function Setting
The Emphasis function is used to modulate the high/low frequencies of the power
spectrum so as to obtain a more average power spectrum density and a better S/N ratio.
The high frequency power spectrum of a typical signal tends to reduce while noise will
increase rapidly as the frequency rises. This is quite opposite to the signals and will
cause a bad S/N ratio, so emphasis will be used to improve this unbalanced situation. In
the Tx or Rx mode, the control bit I/O CMD-2Ch[5] is setup as follows:
Emphasis Enabe Flow:
Flow description:
<82C20>
：
Setup data: 20h. 2Ch[5] = 1 enables the Emphasis.
Audio -- Low Pass Filter & High Pass Filter Function Setting
In a communication system, signal interference and noise from adjacent channels will
corrupt the data to be transmitted/received. Suitable filtering can improve this problem.
The device provides a 3.0kHz broad band and a 2.55kHz narrow band for a low pass filter
as well as a 300Hz high pass filter to filter the sub-tones and signals outside the channel
frequencies. The control bit I/O CMD-2Ch[4-2] is setup as follows:
12.5k LPF & 300 HPF Enable Flow:
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