Glossary of phone design related terms
ABB
Analog Base Band
DBB
Digital Base Band
TPU
Time Processing Unit. A programmable state machine to control events synchronous to the GSM bitclock
TSP
Time Serial Port. Synchronization bus used for timing certain digital control signals.
DSP
Digital Signal Processor
MCU
Micro Controller Unit (the ARM CPU in the Calypso)
BSP
Baseband Serial Port. Communicates digital I/Q samples between ABB and DBB
USP
uController Serial Port. A SPI control interface between the MCU(ARM) in the DBB and the ABB
VSP
Voiceband Serial Port. Communicates speech samples between the DBB(DSP) and the ABB
UL
UpLink?. The direction from the MS to the BTS. (Phone Tx)
DL
DownLink?. The direction from the BTS to the MS. (Phone Rx)

