HT98R068-1 Two-way Radio OTP MCU
Audio Processor Status Reset
When decoding normally, the audio processor processes depending on the signal data
code, frequency and amplitude. Its status (I/O CMD-23h, 30h) will change if the
communication flow meets with that RF ok
signal ok
signal fail
RF fail. When the
audio status changes by a sequence 0
1
0, it can decode again in the next
communication setup. However, sometimes due to using of various combinations, there
is no way to get the audio processor decoding again and it remains the false status.
Hence, we need a mechanism to make it back to the decoding stage to decode again.
There are two ways:
Reset using command (I/O CMD: 10000), but note that this command will make the
original data wrote to the CLI automatically overwritten.
Reset basing on signal. Set the PGA source to be VAG and increase the de-response
delay time to make the audio processor return to none decoding automatically, the
status register will be changed to 0, then switched to the Rx mode to detect the signal
again. But the disadvantage is that it must consum time to delay.
The other situation is sub-audio tail-tone detection status, CTCSS anti-tone (I/O
CMD-30h [0] =1) or DCS off-tone (I/O CMD-23h [1] =1). When decoding a CTCSS
off-tone, the I/O CMD-30h[0]=1, this status will be remained(because it is belong to
respective decode), so we must load I/O CMD: 12000 and make it reset sub-audio
tail-tone decoding detection, set I/O CMD-30h[0]=0 or I/O CMD-23h[1]=0. Hence, take it
to consider that at the moment decoding the tail-tone it excutes the command
immediately when designing.
Internal Audio Function
In the open public radio system (such as aviation communication), when someone wants
to select to call some users or resist to receive irrelevant information, the selective call
function is always applicated in specifying the person to communicate with. When calling
someone, the tranimitter will firstly transmit the specification information of 2 or 5 tones
audio (selective call), then send the sound signal. Each receiver of the same frequency
will receive this radio signal then decodes the data of 2 or 5 tones at the same time and
compare them. If the decoded selective call code is the same with the receiver’s, the
process end will open the speaker to make it heared to complete the communication
information transmission of the ends. Besides, the signals such as DTMF are applied in
keys triggle, can be used in transmitting the data input by the user to the other end to
decode or application of the same selective call use. This product provides two audio
selection, selective call and DTMF, which include transmit encoder and receive decoder
as the following shows.
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