Microprocessor-Controlled Radio Synthesizer - 2

48 EE:rnt1= MICROPROCESSOR-CONTROLLED RADIO SYNTHESIZER 2 by Peter Topping This final instalment of the article deals with the construction and setting up of the multi-purpose RF synthesizer. This has been divided in a number of building blocks to allow its use in a large number of applications, from upgrading surplus SW receivers to providing state-of-the-art tuning on modern tunerheads for the VHF FM band. It will have been evident from Part 1 of this article 0) that the microprocessor- controlled synthesizer is a relatively complex project with many possible con- figurations and applications. To enable its use with many types of receiver (SW, SW/MW, VHF FM), and to allow the user the choice between three types of display, the synthesizer system is divided in a number of sub-units: 1. Microprocessor board; 2. Keypad; 3. One or more displays (these are not necessarily of the same type); 4. Power supply; 5. Synthesizer board; 6. VHF prescaler board (fin up to 150 MHz); 7. SW presc...