The MICRF505 is a true single chip, frequency shift keying
(FSK) transceiver intended for use in half-duplex, bidirectional
RF links. The multi-channeled FSK transceiver is
intended for UHF radio equipment in compliance with the
North American Federal Communications Commission (FCC)
part 15.247 and 249, as well as the European Telecommunication
Standard Institute (ETSI) specification, EN300 220.
The transmitter consists of a PLL frequency synthesizer and
a power amplifier. The frequency synthesizer consists of a
voltage-controlled oscillator (VCO), a crystal oscillator, dual
modulus prescaler, programmable frequency dividers, and a
phase-detector. The loop-filter is external for flexibility and
can be a simple passive circuit. The output power of the
power amplifier can be programmed to seven levels. A lockdetect
circuit detects when the PLL is in lock. In receive mode,
the PLL synthesizer generates the local oscillator (LO) signal.
The N, M , and A values that give th