AM79C202 Legerity, AM79C202 Datasheet - Page 22

• Manufacturer Part Number: AM79C202
• Description: (AM79C202 / AM79212) PCM CODEC
• Manufacturer: Legerity

The transmit path is defined as the section between the analog input to the ASLAC device (VIN) and the GCI voice
output of the ASLAC device A-law/µ-law speech compressor (see the Voice Transmission Path figure in the Technical
Reference). The receive path is defined as the section between the GCI voice input to the ASLAC device speech
expander and the analog output of the ASLAC device (VOUT). All limits defined in this section are tested with B =
0, Z = 0, and X = R = RG = 1.
When RG is enabled, a nominal gain of –6.02 dB is added to the digital section of the receive path.
When AR is enabled, a nominal gain of –6.02 dB is added to the analog section of the receive path.
When AX is enabled, a nominal gain of +6.02 dB is added to the analog section of the transmit path.
When the gains in the transmit path are set to AX = 0 dB and GX = 0 dB, a 1014 Hz sine wave with a nominal
voltage of 0.596 V rms for µ-law and 0.6 V rms for A-law at the ASLAC device analog input will correspond to a level
of 0 dBm0 at the GCI voice output. Under these conditions, the overload level of the transmit path is 1.25 V peak
referenced to VREF.
When the gains in the receive path are set to AR = GR = 0 dB, a 1014 Hz sine wave with a level of 0 dBm0 at the
GCI voice input will correspond to a nominal voltage of 0.596 V rms for µ-law and 0.6 V rms for A-law at the analog
output of the ASLAC device. Under these conditions, the maximum receive output level is 1.25 V peak referenced to
VREF.
When relative levels (dBm0) are used in any of the following transmission characteristics, the specification holds for
any setting of (AX + GX) gain from 0 dB to 12 dB or (AR + GR + RG) from 0 to –12 dB.
These transmission characteristics are valid for 0°C to 70°C and for VCC = +5 V ± 0.25 V.
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Am79212/Am79C202 Data Sheet