ACE9020

ACE9020 is a VHF oscillator, up-converter and prescaler.It is used in an offset modulated transmit architecture where a UHF synthesiser makes the channel selection and a second synthesiser generates a fixed transmit offset.

A VCO signal drives a buffer in ACE9020 to feed an onchip prescaler and transmit up-converter. The prescaler is a dual two-modulus divider and drives the main synthesiser input of the ACE9030. The SSB up-converter suppresses the unwanted transmit sideband.

The VHF oscillator ACE9020 is buffered to drive the auxiliary synthesiser input of the ACE9030 and is locked to the offset frequency. This frequency is modulated by varying the resonant frequency of the external tank circuit. Both this oscillator and the UHF VCO drive the up-converting mixer to generate the transmit signal.

Various power saving modes for battery economy are included. These allow the transmit sections to be shut down during stand-by and the whole chip can be shut down during sleep mode. The circuit techniques used have been chosen to minimise external components and at the same time give very high performance.