SIEMENS AP75
Manual de Servicio

12/2005 Release 1.0

Automatic Power Control (APC) Purpose of the Automatic Power Control (APC) is to generate an envelope signal to control the power ramping up, ramping down and power level of the radio burst. The APC structure is intended to support single slot and multi-slots transmission with smooth power transition when consecutive bursts are transmitted at different power level. It includes a DAC and a RAM in which the shape of the edges (ramp-up and ramp-down) of the envelope signals are stored digitally. This envelope signal is converted to analog by a 10 bits digital to analog converter. Timing of the APC is generated internally and depends of the real time signals coming from the TSP and the content of two registers which control the relative position of the envelope signal versus the modulated I & Q.

Time serial port (TSP) Purpose of the time serial port is to control in real time the radio activation windows of IOTA which are BUL power-on, BUL calibration, BUL transmit, BDL power-on, BDL calibration and BDL receive and the ADC conversion start. These real time control signals are processed by the TPU of DBB and transmitted serially to ABB via the TSP, which consists in a very simple two pins serial port. One pin is an enable (TEN) the other one the data receive (TDR). The master clock CK13M divided by 2 (6.5MHz) is used as clock for this serial port. Voice band Codec (VBC) The VBC processes analog audio components in the uplink path and transmits this signal to DSP speech coder through the voice serial port (VSP). In the downlink path the VBC converts the digital samples of speech data received from the DSP via the voice serial port into analog audio signal. Additional functions such as programmable gain, volume control and side-tone are performed into the voice band codec.

Micro-controller serial port (USP) The micro-controller serial port is a standard synchronous serial port. It consists in three terminals, data transmit (UDX), data receive (UDR) and port enable (UEN). The clock signal is 13MHz clock. The USP receives and sends data in serial mode from and to the external microcontroller and in parallel mode from and to the internal GSM Baseband a Voice A/D D/A modules. The micro-controller serial port allow read and write access of all internal registers under the arbitration of the internal bus controller.

Technical Documentation TD_Repair_L4 M315/AP75_R1.0.pdf Page 16 of 42