Specifications

XT65/XT75 Hardware Interface Description
7.8 Electrical Characteristics of the Voiceband Part
s
XT65_XT75_HD_v01.001 Page 110 of 133 2007-1-8
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7.8.5 Voiceband Transmit Path
Test conditions:
• The values specified below were tested to 1kHz and default settings of audio modes, unless otherwise stated.
• Parameter setup: Audio mode=5 for MICP1 to MICN1 and 6 for MICP2 to MICN2, inBbcGain=0, inCali-
brate=32767, outBbcGain=0, OutCalibrate=16384, sideTone=0
Table 37: Voiceband transmit path
Parameter Min Typ Max Unit Test condition / Remark
Full scale input voltage (peak to
peak) for 3.14dBm0
MICP1 to MICN1 or AGND, MICP2
to MICN2 or AGND
1.6 V MICPx must be biased with
1.25V (VMIC/2)
Nominal input voltage (peak to
peak) for 0dBm0
MICP1 to MICN1 or AGND, MICP2
to MICN2 or AGND
1.1 V MICPx must be biased with
1.25V (VMIC/2)
Input amplifier gain in 6dB steps
(inBbcGain)
0 42 dB Set with AT^SNFI
Fine scaling by DSP (inCalibrate) -
∞ 0 dB Set with AT^SNFI
Microphone supply voltage VMIC 2.4 2.5 2.6 V
VMIC current 2 mA
Idle channel noise -82 -76 dBm0p
Signal to noise and distortion 70 77 dB
Frequency response
1
0Hz - 100Hz
200Hz
300Hz - 3350Hz
3400Hz
4000Hz
>
4400Hz
1.
This is the frequency response from a highpass and lowpass filter combination in the DAC of the baseband
chip set. If the PCM interface is used, this filter is not involved in the audio path. Audio mode 1 to 4 incor-
porate additional frequency response correction filters in the digital signal processing unit and are adjusted
to their dedicated audio devices (see Table 35).
-0.2
-1.1
-0.7
-39
-34
0.1
-75
dB