Digital Radio Baseband Processor 2 CMX980A Advance Information
2000 MX-COM, Inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 Doc. 20480201.001
4800 Bethania Station Road, Winston-Salem, NC 27105-1201, USA All trademarks and service marks are held by their respective companies
CONTENTS
Section Page
1 Block Diagram................................................................................................................4
2 Signal List.......................................................................................................................5
3 External Components....................................................................................................7
3.1 Rx Inputs ............................................................................................................................. 7
3.2 Tx Outputs........................................................................................................................... 7
4 General Description.......................................................................................................8
4.1 Connection and Decoupling of Power Supplies .................................................................. 8
4.2 Programmable FIR Filter Architecture................................................................................. 9
4.3 Tx Data Path........................................................................................................................ 9
4.3.1 Modulator .............................................................................................................................10
4.3.2 Filters....................................................................................................................................10
4.3.3 Gain Multiplier ......................................................................................................................10
4.3.4 Offset Adjust.........................................................................................................................10
4.3.5 Sigma-Delta D-A Converters and Reconstruction Filters.....................................................10
4.3.6 Phase Pre-distortion.............................................................................................................10
4.3.7 Ramping Output Amplitude..................................................................................................10
4.3.8 Symbol Clock Phase Adjustment.........................................................................................11
4.3.9 1.5.3.9 Direct Write to Tx 79-tap Filter Input ........................................................................11
4.3.10 Test Access to DAC Input....................................................................................................11
4.4 Rx Data Path..................................................................................................................... 11
4.4.1 Anti-Alias Filtering and Sigma-Delta A-D Converters...........................................................11
4.4.2 Rx FIR Filters .......................................................................................................................11
4.4.3 Offset Registers....................................................................................................................12
4.4.4 I and Q Channel Gain...........................................................................................................12
4.5 Auxiliary Circuits................................................................................................................ 12
4.5.1 10-Bit DACs..........................................................................................................................12
4.5.2 10-Bit ADC ...........................................................................................................................12
4.5.3 Power Ramping and Control................................................................................................12
4.6 IRQ Function ..................................................................................................................... 12
4.7 Serial Interface .................................................................................................................. 13
4.7.1 Command Interface..............................................................................................................14
4.7.2 Command Read Interface....................................................................................................14
4.7.3 Rx Data Interface .................................................................................................................14
4.7.4 Transmission of Data ...........................................................................................................15
4.7.5 Command Control Serial Word ............................................................................................16
4.7.6 Coefficient Memory ..............................................................................................................17
4.7.7 Auto Power Save Mode........................................................................................................18