Block Diagrams Descriptions; Receiver Path - Motorola MTH500 Service Manual

Block Diagrams Descriptions

Receiver Path

68P02963C70-O
The block diagrams descriptions cover Receiver Path, Transmitter Path, Digital Section, and
Frequency Generation Section.
The received signal (see Figure 2) from the antenna is directed by the Antenna Switch to the
Front Filter.
LC
Front Filter
IL=2.5dB
Figure 2 Receive Path Block Diagram
This block-type filter, which defines the receive frequency range, blocks the half IF and image
frequency entry, and reduces the RF oscillator leakage. The signal is mixed with the local os-
cillator to create the first IF at 109.65 MHz. The signal is filtered by the crystal filter and sent
to the WPIC ASIC.
The WPIC performs down conversion to the second IF at baseband frequency (0 Hz) and con-
verts the second IF analog signals into digital-in-phase (I) and Quadrature (Q) formats. This
WPIC
Theory of Operation
(DSP)
2 - 5