A MODULATOR AS A CUSTOMER DESIGNED SILICON INTEGRATED CIRCUIT

摘要

This Report describes the development of a complex analogue circuit that is suitable for production on a single silicon chip. The circuit is produced to a close specification for external supplies and signals as well as working over a wide temperature range. The numbers of external components are kept to a minimum with the microphone input fed via a blocking capacitor and a further capacitor added to reduce the audio gain at high frequencies. One external resistor is required to be adjusted on test to set the audio d. c. Levels applied to the modulator, the range of values required depend on the spread in transistor parameters experienced in practice.