AMIS-53000 Datasheet, PDF (52/99 Pages) AMI SEMICONDUCTOR – Frequency Agile Transceiver

AMIS-53000 Frequency Agile Transceiver
Data Sheet
6.5.1.4. Data Recovery
Table 36: Receiver Configuration
RX Configuration Registers
0X0E RX Config
0X1F CDR
Options A
Bit 2 Mod Bit 0 Demod
0
FFT
0
FM
1
PLL
0
NA⁶
1
AM
1
NA⁶
0X0B Data Rate
Format
Bit 3
0
1
0
Code
NRZ¹
Man
NRZ¹
0X1E
Filter
Slice
Bit 1:0
SLICE ²
SLICE²
SLICE ²
1
Man
SLICE²
0
NRZ
SLICE²
1
Man
SLICE²
0
NRZ
SLICE²
1
Man
SLICE²
Data Rage
>20k – 128k
>20k – 128k
<20k
<20k
1k – 19.2k
1k – 19.2k
1k – 19.2k
1k – 19.2k
Preamble CDR
10Pattern
10Pattern
10Pattern
All 1 or 0’s
CW
CW
CW
CW
Yes³
Yes³
Yes³
Yes³
Opt⁷
Opt⁷
Opt⁷
Opt⁷
SOF
No
No⁴
No
0X55
0XAA
0X55
0X0A
0X55
0X0A
Notes:
1. Long strings of 1’s or 0’s will degrade the performance of the CDR circuits.
2. SLICE can use the parameters in Table 38.
3. Yes indicates that CDR is always used to detect the data. (SeeTable 41 and Table 42 for CDR parameters)
4. Manchester encoded data requires a SOF. A unique SOF (suggested 0x66) is used to bit-align the Manchester decoder to the recovered data.
5. 0X55 or 0X0A SOF have the following requirements:
0x55 The following is suggested:
It is suggested that CDR with fast phase alignment be enabled
It is suggested that CDR with activity check be enabled with 8 or 16 bit times
It is suggested that the preamble be long enough to trigger activity check (10 or 20 bit times)
0x0A The following is suggested:
It is suggested that CDR with fast phase alignment be enabled
It is suggested that CDR with activity check be enabled with 4 bit times
It is suggested that the preamble be long enough to trigger activity check
6. NA indicates that the parameter is not available for the AM/OOK modulated signals.
7. OPT indicates that CDR is an option to detect the data however, it is recommended that CDR be used. (See Table 41 andTable 42 for CDR parameters)
AM Data Recovery with RSSI
The logarithmic AM detector, used with OOK/ASK modulated signals, produces an RSSI output signal with approximately 18mV/dB
output level. A low pass filter provides additional filtering matched to the AM signal data rate (1.2, 1.8, 2.4, 4.8, 7.2, 9.6, 14.4,
19.2kbps). This filtered signal is sampled and compared to the slice threshold to recover the digital data. The slice threshold can be
set to a fixed value or it can use a signal tracking circuit to set a peak or average threshold.
The RSSI output signal can also be applied to a clock and data recovery circuit, which synchronizes an AMIS-53000 internal clock with
the incoming data rate (See CDR Operation).
Setup registers descriptions:
Slice Threshold- The slice operation needs to be selected, fixed or automatic. The value for the fixed threshold needs to be
set.
Filter/Slice- Filter settings and slice mode need to be selected.
Slice Threshold
Sets the data slice level for AM reception. This threshold is used when the slice method sets in the AM data filter and slice options is
set to DAC.
AMI Semiconductor – Aug. 05, Rev. 1.0
52
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