bt8375kpf Conexant Systems, Inc., bt8375kpf Datasheet - Page 202

• 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.

3.14 Clock Rate Adapter Registers
LFGAIN[3:0]
VSEL[3:0]
3-84
091— CLAD Frequency Select (CSEL)
VSEL[3]
7
Loop Filter Gain—Determines CLAD jitter tolerance and jitter attenuation characteristics by
selecting the NCO loop filter's proportional phase error gain. Lower gain values improve jitter
tolerance by reducing phase response time, but provide less jitter attenuation. Higher gain
values increase the phase response time and improve jitter attenuation at the expense of loop
acquisition time.
NOTE:
CLADV Frequency Select—Applicable only if CEN [addr 90] is active. Picks one of eight
CLAD divider chain frequencies to feed back to the CPHASE detector. (Refer to
through
for further division before phase detector comparison.
VSEL[2]
6
2-9
Loop instability or acquisition failures may result from incorrectly programmed
LFGAIN values. Typically, LFGAIN is programmed to provide a minimum 3 Hz loop
bandwidth and 20 dB/decade jitter attenuation with 6 Hz filter cutoff frequency.
LFGAIN values of 5 or 6 are typically chosen to meet jitter requirements.
for programming examples.) The selected CLADV frequency passes to VSCALE
VSEL[1]
5
VSEL
0000
0001
0010
0011
0100
0101
0110
0111
1xxx
LFGAIN
VSEL[0]
0000
1111
4
|
Conexant
OSEL[3]
T1/E1 line rate x 2
3
Fully Integrated T1/E1 Framer and Line Interface
CLADV Frequency (kHz)
Proportional Gain
16,384
1/2
1024
2048
4096
8192
2560
1544
1536
1/2
OSEL[2]
|
15
2
0
XSEL
(addr 090)
OSEL[1]
Bt8370/8375/8376
1
Tables 2-8
N8370DSE
OSEL[0]
0