bt8375kpf Conexant Systems, Inc., bt8375kpf Datasheet - Page 160

• Manufacturer Part Number: bt8375kpf
• Description: Single Chip Transceivers For T1/e1 And Integrated Service Digital Network Isdn Primary Rate Interfaces Systems
• Manufacturer: Conexant Systems, Inc.

3.7 Receive LIU Registers
OOR_BLOCK
RLB0
LONG_EYE
LPF[6:0]
VGA_MAX[5:0]
Table 3-10. VGA Maximum Settings for Receive Sensitivity
3-42
023— RPLL Low Pass Filter (LPF)
024— Variable Gain Amplifier Maximum (VGA_MAX)
Rx Sensitivity
VGA_MAX
—
—
7
7
Disable Automatic RLBO—When active, automatic RLBO switching is disabled when the
ADC is out of range.
Receiver Line Build Out—Enables receive signal attenuation.
Eye Open Timeout
RPLL Low Pass Filter Gain—Reserved for CONEXANT Production test. Determines clock
recovery RPLL input jitter tolerance and the worst case signal acquisition time. The initial
default value is optimized for maximum input jitter tolerance.
VGA Maximum—The processor can limit receiver sensitivity by programming the maximum
allowable input signal gain into the VGA_MAX register. This option is used for short and
medium haul interfaces that must declare loss of signal when the receive level falls below a
certain level. The default value is 0x3F for Bt8370 and 0x2F for Bt8375/6.
sensitivity value is the received signal level (below nominal) at which analog loss of signal
(RALOS) occurs. These values are applicable only when the RLBO and the PRE_EQ are
disabled. RLBO is disabled when the receive level is less than about –8 dB, or when RLBO is
forced off: RLBO = 0 (reg RLIU_CR [add 022]. The PRE_EQ is disabled when the receive
level is greater than about –24 dB, or when it is forced off: register PRE_EQ [addr 02A] =
(10XXXXXX).
LPF[6]
0x0B
0 dB
—
Table 3-10
6
6
–5 dB
0x12
VGA_MAX[5]
contains approximate VGA_MAX settings for the receive sensitivity values. The
LPF[5]
5
5
–10 dB
0 = normal operation
1 = disable RLBO switching
0 = RLBO forced off (normal operation)
1 = enable automatic RLBO
0 = 4096 bit timeout
1 = 8192 bit timeout (normal operation)
0x19
VGA_MAX[4]
–15 dB
LPF[4]
0x1E
4
4
Conexant
–20 dB
0x23
VGA_MAX[3]
LPF[3]
3
3
Fully Integrated T1/E1 Framer and Line Interface
–25 dB
0x27
VGA_MAX[2]
LPF[2]
–30 dB
0x2C
2
2
–35 dB
VGA_MAX[1]
0x2F
LPF[1]
Bt8370/8375/8376
1
1
–40 dB
0x33
VGA_MAX[0]
N8370DSE
LPF[0]
0
0
–45 dB
0x37