ata5780 ATMEL Corporation, ata5780 Datasheet - Page 14

• Manufacturer Part Number: ata5780
• Description: Uhf Ask/fsk Receiver
• Manufacturer: ATMEL Corporation

4.3.2
4.3.2.1
14
Atmel ATA5780 [Preliminary]
Rx Digital Signal Processing
Demodulator
DMCRx, DMPGx
The Rx DSP block performs digital signal processing, decoding, and checking of the Rx sam-
ples from the ADC. It delivers the raw data at the TRPA/B pins, the decoded data at the TMDO
output and finally the buffered data words from the Rx buffer.
Figure 4-2.
Note:
Dedicated demodulators are available for reception path A and B. This allows unique settings
for each data path. The only limiting factor for differences is the common channel filter fixing a
common bandwidth for both data paths. ASK/FSK modulation, data rates, and deviation can
be set independently.
The demodulator supports the following modulation schemes:
Fading up to 1dB per bit is tolerated by the demodulator.
Data rates for NRZ or symbol rates for other coding schemes:
A matched filter is available for Manchester coding; therefore the supported data rates are
higher than calculated from the symbol rate. The Manchester data rate range is: 0.25Kbit to
80Kbits.
The demodulator provides DPLL-based data clock recovery for optimized sampling positions
that tolerates single-bit errors.
• ASK
• FSK with a deviation range of 0.5KHz to 80KHz
• GFSK
• Min: 0.5KBaud
• Max: 40Kbaud
Channel Filter
Signal from
DMCDx
x represents path A and B
Simplified Demodulator and Clock Recovery Block for One Path
Demod.
Demod.
ASK
FSK
RXFOx
DMCRx, SASKx
1
0
DMMx, DMHAx
DMMx, DMATx
Amplitude
Check
Filter
Data
DMDRx
Recovery
Clock
9207BS–RKE–01/11
Symbol Clock
TRPx
MANx
AMPx
CARx