RS8973 Mindspeed Technologies, RS8973 Datasheet - Page 67

• Manufacturer Part Number: RS8973
• Description: Single-chip Sdsl/hdsl Transceiver
• Manufacturer: Mindspeed Technologies

RS8973
Single-Chip SDSL/HDSL Transceiver
tx_gain[3:0]
noise_histogram_th_high)
A 2-byte read/write register interpreted as a 16-bit, 2s-complement number. The range of meaningful values is
limited to positive integers between 0x0000 and 0x7FFF. The value of this register is compared to the absolute
value of the slicer error signal produced by the detector. A count of error samples that exceeds this threshold
(greater than) is accumulated in the noise-level histogram meter.
ep_pause_th_high)
A 2-byte read/write register interpreted as a 16-bit, 2s-complement number. The range of meaningful values is
limited to positive integers between 0x0000 and 0x7FFF. The value of this register is compared to the absolute
value of the slicer error signal produced by the detector. The result of this comparison (slicer error greater than
this threshold) is used to initiate a pause condition by zeroing the output of the error predictor correction signal
before subtraction from the receive signal path. Error predictor coefficient updates are not affected. The pause
condition lasts for a fixed 5-symbol period from the time the threshold was last exceeded.
N8973DSD
0x29—Transmitter Gain Register (tx_gain)
0x2A, 0x2B—Noise-Level Histogram Threshold Register (noise_histogram_th_low,
0x2C, 0x2D—Error Predictor Pause Threshold Register (ep_pause_th_low,
—
7
Transmit Gain—A 4-bit, 2s-complement, read/write field controlling the transmitter gain.
Upon initialization, the value in the Transmitter Calibration Register [tx_calibrate; 0x28] can
be written into this register by software, to set the transmitter gain to the nominal value.
Alternatively, the user can set it to another desired value. The transmitter gain settings are
relative to the setting that provides a nominal output power of 13.5 dBm.
—
6
tx_gain[3:0]
tx_gain[3]
1000
1001
1010
1011
1100
1101
1110
1111
0000
0001
0010
0011
0100
0101
0110
0111
5
Preliminary Information
tx_gain[2]
Relative Transmitter Gain (dB)
4
Conexant
tx_gain[1]
–1.60
–1.36
–1.13
–0.91
–0.69
–0.48
–0.27
–0.07
3
0.13
0.32
0.51
0.70
0.88
1.05
1.23
1.40
tx_gain[0]
2
—
3.3 Register Description
1
3.0 Registers
—
0
3-21