Datasheet

73M1866B/73M1966B Data Sheet DS_1x66B_001
58 Rev. 1.6
TX Level
Analog Gain
Digital Gain
Ana+Dig
dBm TxBst DAA1 DAA0 dB TXDG dB dB
-17 0 1 1 -8 1001_1010 -8.75 -16.75
-16 0 1 1 -8 1010_0110 -7.75 -15.75
-15
0
1
1
-8
1010_1110
-6.75
-14.75
-14 0 1 1 -8 0100_0010 -5.75 -13.75
-13 0 1 1 -8 0100_1010 -4.75 -12.75
-12 0 1 1 -8 0101_0010 -3.75 -11.75
-11 0 1 1 -8 0101_1010 -2.75 -10.75
-10 0 1 1 -8 0110_0110 -1.75 -9.75
-9
0
1
1
-8
0110_1110
-0.75
-8.75
-8 0 1 1 -8 0000_0010 0.25 -7.75
-7 0 1 1 -8 0000_1010 1.25 -6.75
-6 0 1 0 -4 0110_0110 -1.75 -5.75
-5 0 1 0 -4 0110_1110 -0.75 -4.75
-4 0 1 0 -4 0000_0010 0.25 -3.75
-3
0
1
0
-4
0000_1010
1.25
-2.75
-2 1 1 1 -2 0000_0010 0.25 -1.75
-1 0 0 1 0 0110_1110 -0.75 -0.75
0 0 0 1 0 0000_0010 0.25 0.25
1 0 0 1 0 0000_1010 1.25 1.25
2 1 1 0 2 0000_0010 0.25 2.25
3
0
0
0
3
0000_0010
0.25
3.25
4 0 0 0 3 0000_1010 1.25 4.25
5 1 0 0 6 0110_1110 -0.75 5.25
6 1 0 0 6 0000_0010 0.25 6.25
Note (1) 1 0 0 6 0000_1010 1.25 7.25
Note (1) 1 0 0 6 0001_0010 2.25 8.25
Note (1)
1
0
0
6
0001_1010
3.25
9.25
Note (1) 1 0 0 6 0010_0110 4.25 10.25
Note (1) 1 0 0 6 0010_1110 5.25 11.25
Note (1) 1 0 0 6 0011_0110 6.25 12.25
Note 1. Tx Data is assumed small enough that the combination of Tx Data and TXDG is less than 1.25 dBm.
8.8.1.2 Receive Gain Scaling
On the receive side, a 0 dBm receive signal on the line results in ~0 dBm at the PCM interface.
Means is provided to adjust receive signal path gain by use of a digital gain stage. This gain value is
controlled by Register 0x09[7:0] (RXDG). The gain values are explained in Table 33.
The two RXG bits (Register 0x14[1:0]) control the value of the receiver analog gain. The RXG bits must
be set to 10 to enable 0 dB gain in the receive path.
For the best S/N performance it is recommended to use a gain value up front in the analog domain. The
digital control should be used to fine-tune the receiver signal path gain.
When the received line signal exceeds a voltage level greater than specified by ITU-T
Recommendation G.711, the receive gain must be reduced to prevent saturation and clipping within
the receive signal processing path.