msm7586-01 Oki Semiconductor, msm7586-01 Datasheet - Page 16

• Manufacturer Part Number: msm7586-01
• Description: Shift Qpsk Modem/adpcm Codec
• Manufacturer: Oki Semiconductor

Input voice signal
GSX2
VOXO pin
VOXI pin
Regenerated voice
VFRO
¡ Semiconductor
VOXO
Transmit VOX function signal output.
VOX function is used to recognize the presence or absence of the transmit voice signal by
detecting the signal energy. "H" and "L" levels on this pin correspond to the presence and the
absence, respectively. This result also appears at the register data CRC7 - B7. The signal energy
detect threshold is set by the control register data CRC6 - B6, B5.
VOXI
Signal input for receive VOX function.
The "H" level on VOXI indicates the presence of voice signal, the decoder block processes normal
receive signal, and the voice signal appears at analog output pins . The "L" level indicates the
absence of voice signal, the background noise generated in this device is transferred to the analog
output pins. The background noise amplitude is set by the control register CRC6. Because this
signal is ORed with the register data CRC6 - B3, the control register data CRC6 - B3 should be set
to digital "0".
Note: The VOXO and VOXI pin function are enabled when CRC6 - B7 is set to "1".
pin
pin
Regenerated voice signal
Voice detection time
Tvxon
generation time
Voice
Voice
(a) Transmission Side VOX Function Timing Diagram
(b) Receive Side VOX Function Timing Diagram
Figure 7 VOX Function
noise generation time
Internal background
Silience
Silience
Silence detection time
(Hangover time) Tvxoff
Voice
Voice
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