Vorrichtung und Verfahren zum Frequenzwechsel

摘要

A microprocessor controlled circuit and associated firmware program provide a capability to change output frequencies when required. A plurality of frequency generating devices (X1, X2) are included, and logic circuitry (46, 48, 50) is used to determine which frequency generator is coupled to the microprocessor (30) to provide the desired output frequency. The logic circuitry (46, 48, 50) is controlled by the microprocessor (30) in accordance with a comparison of a data pattern stored in the internal random access memory of the microprocessor (30) with at least one of a plurality of data patterns stored in a read only memory (36), which data patterns represent the frequency generating devices (X1, X2). The arrangement is particularly applicable to test devices to provide a capability of testing units which may operate under different operating frequencies.