Digital PMR Radio Processor
CMX7131/CMX7141
CONTENTS
Section
Page
1
2
3
Brief Description...................................................................................................................... 2
Block Diagram.......................................................................................................................... 7
Signal List................................................................................................................................. 8
3.1
Signal Definitions........................................................................................................ 10
4
External Components............................................................................................................ 11
4.1
4.2
4.3
Recommended External Components ....................................................................... 13
PCB Layout Guidelines and Power Supply Decoupling.............................................. 14
CMX994 Interface....................................................................................................... 16
5
General Description............................................................................................................... 18
5.1
5.2
Features...................................................................................................................... 18
System Design............................................................................................................ 19
5.2.1 Vocoder Implementation ...................................................................................... 19
5.2.2 Data Transfer ....................................................................................................... 20
5.2.3 RSSI Measurement (LD Mode only) .................................................................... 20
5.2.4 Serial Memory Connection (LD Mode only) ......................................................... 21
5.2.5 CMX994 Connection (I/Q Mode only) .................................................................. 21
5.2.6 Hardware AGC – AuxADC1 Connection.............................................................. 21
5.2.7 RSSI Measurement (I/Q Mode only).................................................................... 21
Introduction................................................................................................................. 22
5.3.1 Modulation............................................................................................................ 22
5.3.2 Internal Processing .............................................................................................. 25
5.3.3 Frame Sync Detection and Demodulation ........................................................... 25
5.3.4 FEC and Coding................................................................................................... 29
5.3.5 Voice Coding........................................................................................................ 29
5.3.6 Radio Performance Requirements....................................................................... 29
5.3
6
Detailed Descriptions............................................................................................................ 30
6.1
6.2
Xtal Frequency............................................................................................................ 30
Host Interface ............................................................................................................. 30
6.2.1 C-BUS Operation ................................................................................................. 30
Function Image™ Loading.......................................................................................... 32
6.3.1 FI Loading from Host Controller........................................................................... 33
6.3.2 FI Loading from Serial Memory............................................................................ 35
NXDN Standard Vocoder Interface ............................................................................ 36
6.4.1 Support for I2S Mode............................................................................................ 36
Device Control ............................................................................................................ 36
6.5.1 General Notes...................................................................................................... 37
6.5.2 Interrupt Operation............................................................................................... 37
6.5.3 Signal Routing...................................................................................................... 37
6.5.4 Modem Control..................................................................................................... 38
6.5.5 Tx Mode NXDN Formatted .................................................................................. 39
6.5.6 Tx Mode ............................................................................................................... 40
6.5.7 Tx Mode PRBS .................................................................................................... 44
6.3
6.4
6.5
2014 CML Microsystems Plc
Page 3
D/7141_FI-3.x/6
CMLMICRO [ CML MICROCIRCUITS ]
