SAA7706H/N107 NXP Semiconductors, SAA7706H/N107 Datasheet - Page 14

• Manufacturer Part Number: SAA7706H/N107
• Manufacturer: NXP Semiconductors

Specifications of SAA7706H/N107

• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Compliant

Philips Semiconductors
8.1.2
A differential input with volume control for mixing to the
front left or front right of both DAC outputs is provided. The
inputs consist of a PHONE and NAV input. Both are
accompanied with their ground return lines. After selection
of PHONE or NAV the volume can be changed from about
+18 to 22.5 dB in 27 steps and mute (MIX output). This
signal can be added to the left and/or right front DAC
channels.
The output signals of both input circuits can also be
switched to ADC1 and/or ADC2, depending on the settings
of audio input control 1 (AIC1) and audio input control 2
(AIC2), without volume control (see Fig.3).
2001 Mar 05
handbook, full pagewidth
handbook, full pagewidth
Car radio Digital Signal Processor (DSP)
R
CONTROL
EALIZATION OF THE AUXILIARY INPUT WITH VOLUME
Audio
FM
Fig.5 Audio gain through ADC and digital filter path to DSP.
GAIN
GAIN
Fig.6 FM gain path through stereo decoder to DSP1.
831 mV (RMS)
660 mV (RMS)
ADC
ADC
14
8.1.3
The gain of the circuit has a maximum of 2.26 (7.08 dB).
This results in an input level of 368 mV for full-scale, which
means 0 dB (full-scale) at the DSP1 input via the stereo
decoder (see Fig.6). The gain can be reduced in steps of
1.5 dB. When the gain is set to 3.4 dB the input level
becomes 1229 mV for full-scale. This setting accounts for
the 200 mV (RMS) input sensitivity at 22.5 kHz sweep and
a saturation of the input at 138 kHz sweep.
RDS update: for RDS update the fast access pin SEL_FR
must be made HIGH. In that case the FM_RDS signal also
goes through the path that was set for FM_MPX. In this
situation the signal must be obtained via the FM_RDS
input and a noise sample can be retrieved. The input
FM_MPX gets high-ohmic. Charging of the coupling
capacitor connected to pin FM_MPX is no longer possible.
DECODER
5 dB GAIN
3 dB GAIN
DECODER
3 dB GAIN
STEREO
5 dB GAIN
DIGITAL
FILTER
STEREO
DIGITAL
AUDIO
FILTER
AUDIO
R
EALIZATION OF THE
0 dB (full-scale)
2 dB (full-scale)
0 dB (full-scale)
DSP2
DSP1
DSP2
DSP1
MGT461
MGT462
FM
INPUT CONTROL
Product specification
SAA7706H