A Base-band Codec For Digital Cellular Telephony
13 February 1991
A base-band codec for the pan-European digital cellular telephone system integrates all the data-conversion circuitry required for signal processing and for auxiliary control such as automatic frequency and gain control, and transmitter power control. This mixed analog-digital sub-system has two 8b DIA converters (DAC), a 9b DAC, a 10b DAC, two 10b sigma-delta AID converters and two programmable gain amplifiers (PGA) in the analog portion. (Figure 1) The digital section of the chip has two sets of decimators, equalizers, de offset correction logic, and also provides control and timing. The four major functional blocks are the receive section, transmit section, auxiliary control, digital control and timing.