Service Manual

GSM-204-323
RF equipment detail
31st Oct 01
Tech. 5–2
Technical Description: Horizon macro outdoor
CONTROLLED INTRODUCTION
68P02902W02-A
Receive (Rx)
RF hardware
Receiver RF hardware consists of the SURF module and optional Tx block
receive path, and the receive section of the CTU.
The SURF module provides bandpass filtering and low-noise amplification for up
to three sectors, with diversity receive antenna signals, together with switching
to CTUs.
CTU Rx role
The CTU provides the following receive functions:
 Receiver tuning (on a timeslot basis) to any receive channel frequency.
 Demodulation and equalization of the receive channel signal.
 Measurement of the Received Signal Strength Indication (RSSI) and
signal quality.
 Recovery of received data from the demodulated radio channel.
 Channel decoding of the received data and processing of the recovered
signal. Traffic data is passed on to the MCUF for routeing to the MSC.
 Digital interface to the SURF module, which controls selection by the
SURF switch of the receive signals from the appropriate antenna.
 Comparison and processing of an additional receive path from a second
diversity antenna input to compensate for multipath fading and
interference.