Datasheet

TEF6901A_3 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 03 — 20 March 2008 37 of 107
NXP Semiconductors
TEF6901A
Integrated car radio
8.2.5 Write mode: data byte AGC
Table 34. AGC - format of data byte 04h with default setting (buffered)
7 6 5 4 3 2 1 0
AGCSW IFGAIN 0 0 AGC1 AGC0 KAGC LODX
00 0000
Table 35. AGC - data byte 04h bit description
Bit Symbol Description
7 AGCSW RF AGC switch
0 = no control of unused RF AGC
1 = unused AM RF AGC PIN diode at FM mode, or unused FM RF
AGC PIN diode at AM mode is supplied with a constant current for fixed
attenuation
6 IFGAIN IF gain
0 = IF gain for low loss 10.7 MHz filter
1 = increased IF gain (3 dB) for high loss 10.7 MHz filter
5 and 4 - reserved; 0 = normal operation
3 and 2 AGC[1:0] setting of RF AGC threshold voltage
FM mixer 1 input voltage (RMS value)
00 = 24 mV
01 = 17 mV
10 = 12 mV
11 = 9 mV
AM mixer 1 input voltage (peak-to-peak value)
00 = 1000 mV
01 = 700 mV
10 = 500 mV
11 = 350 mV
1 KAGC keyed AGC
FM mode
0 = keyed AGC off
1 = keyed AGC on; the AGC start level is shifted to a value 10 dB above
the standard AGC start level, when the level voltage of the wanted RF
signal is below the threshold level voltage for narrow-band AGC
AM mode
0 = RF cascode AGC enabled with full range
1 = RF cascode AGC enabled with limited range
0 LODX FM: local switch
0 = standard operation (DX)
1 = forced FM RF AGC attenuation (LOCAL)
AM: trigger signal from AM IF noise blanker to AM audio noise blanker
0 = trigger signal active for low modulation (m < 0.05) only
1 = trigger signal always active, independent of modulation