ERM HR C6000, Руководство пользователя

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as weighting, de-emphasis, compression, and decompression. Users can select the required
functions according to their needs. In the transceiver mode, the user can select the 12.5KHz/25KHz
channel filter, and in order to prevent excessive modulation, the limiter is embedded in the filter.
Mic_in ADC Compression Aggravation Filter FM modulation Tr_I/Mod1
Tr_Q/Mod2
Audio_out Decompression To increase Filter Phase
discrimination Recv_I
Recv_Q
Figure 6.1 FM Transceiver Block Diagram
6.1 FM send
In the analog mode, the HR_C6000 can only work in simplex mode, and the analog transmit
channel is opened by configuring register 0x60=0x80. The speech is sampled and converted into a
digital signal by the ADC in Codec. After the HR_C6000 internal compression and weighting
module performs audio signal processing, it passes through the 12.5KHz/25KHz channel filter to
improve the ACPR of the transmitted signal.
The transmission of voice and signaling such as analog voice, analog/digital sub-tone (CTCSS and
CDCSS), DTMF, 2-tone/5-tone and MSK is mainly supported on the above analog channels.
Bandpass filter
The HR_C6000 has an optional bandpass filter with a signal bandwidth of 300Hz to 3400Hz. The
bandpass filter can be turned on by configuring Register 0x34[7]=1’b1.
Figure 6.2 Bandpass filter spectral response – OMISSIS