CMX881 查看數據表（PDF） - CML Microsystems Plc

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CMX881

Baseband Processor for PMR and Trunked Radios

CML Microsystems Plc 

PMR Signalling Processor

CMX881

Section

CONTENTS

Page

1.0 Features........................................................................................................................1

1.1 Brief Description............................................................................................................1

1.2 Block Diagram...............................................................................................................7

1.3 Signal List .....................................................................................................................8

1.4 External Components .................................................................................................. 10

1.4.1 PCB Layout Guidelines and Power Supply Decoupling ................................... 11

1.4.2 Modulator Outputs .......................................................................................... 12

1.5 General Description..................................................................................................... 13

1.5.1 Sleep Mode and Auto Start Up........................................................................ 14

1.5.2 Auxiliary ADC ................................................................................................. 14

1.5.3 Receive Mode................................................................................................. 15

1.5.4 Transmit Mode................................................................................................ 22

1.5.5 FFSK/MSK Data packeting ............................................................................. 26

1.5.6 C-BUS Operation ............................................................................................ 28

1.6 C-BUS Register Description ........................................................................................ 29

1.7 Application Notes ........................................................................................................ 47

1.7.1 CRC and Parity information ............................................................................ 47

1.8 Performance Specification........................................................................................... 48

1.8.1 Electrical Performance.................................................................................... 48

1.8.2 Packaging....................................................................................................... 58

Table

Page

Table 1 Concurrent Rx Signalling Modes Supported by the CMX881 ....................................... 15

Table 2 CTCSS Tones ............................................................................................................. 18

Table 3 DCS Modulation Modes............................................................................................... 18

Table 4 DCS 23 Bit Codes ....................................................................................................... 19

Table 5 Selcall Tones .............................................................................................................. 20

Table 6 Concurrent Tx Modes Supported by the CMX881 ........................................................ 22

Table 7 Data Frequencies for each Baud Rate ......................................................................... 25

Table 8 DTMF Tone Pairs and Corresponding Tx Programming Codes ................................... 26

Table 9 Maximum Data Transfer Latency................................................................................. 27

Figure

Page

Figure 1 Block Diagram ............................................................................................................. 7

Figure 2 Recommended External Components ........................................................................ 10

Figure 3 Power Supply Connections and De-coupling .............................................................. 11

Figure 4 Modulator output components to achieve -100dB/decade roll-off................................ 12

Figure 5 Rx Audio Filter Frequency Response ......................................................................... 16

Figure 6 De-emphasis Curve for TIA/EIA-603 Compliance....................................................... 16

Figure 7 Low Pass Sub-Audio Band Filter for CTCSS and DCS ............................................... 17

Figure 8 25kHz Channel Audio Filter Response Template........................................................ 23

Figure 9 12.5kHz Channel Audio Filter Response Template..................................................... 23

Figure 10 Audio Frequency Pre-emphasis Template ................................................................ 24

Figure 11 Modulating Waveforms for 1200 and 2400 Baud FFSK/MSK Signals....................... 25

Figure 12 C-BUS Transactions................................................................................................. 28

Figure 13 Possible PMR Configuration..................................................................................... 47

Figure 14 C-BUS Timing.......................................................................................................... 56

 2004 CML Microsystems Plc

5

D/881/7

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