Motorola MTM700

4.2 - 2 MTM700 Mobile Radio / Detailed Service Manual THEORY OF OPERATION (800 MHz)
Receiver Section
The receiver section includes the following main components:
• Antenna Switch
• Limiter
• Front Pre-selector Filter
• Low Noise Amplifier (LNA)
• Second Pre-selector Filter
•Mixer
• IF Filter
• IF Amplifier
• Dynamic Range Extension Circuit
• IF Digitizing Subsystem
The IF Digitizing Subsystem performs the following functions:
• Carries out amplification and down conversion of the signal into the second IF.
• Performs IF AGC.
• Converts the second IF analog signal into baseband digital I & Q format.
• Transmits the I & Q baseband data to the DSP for further processing.
• Synthesizes the second LO frequency.
• Synthesizes the Sigma-Delta clock.
• Calculates the received signal strength.