MULTI-STAGE HETERODYNE CONTROL CIRCUIT

摘要

A circuit for controlling an RF generator, the circuit including first and second heterodyne stages. The first heterodyne stage receives an input signal, which is based on a characteristic of an RF signal generated by the RF generator, and is configured to: mix the input signal with a first mix signal to generate a first heterodyne signal and to filter the first heterodyne signal through a low pass filter. The second heterodyne stage receives the filtered first heterodyne signal and is configured to: mix the filtered first heterodyne signal with a second mix signal to generate a second heterodyne signal and to filter the second heterodyne signal through a band pass filter. A detection stage converts the filtered second heterodyne signal to a DC signal, and a power control stage receives the DC signal and controls the RF signal in response to the DC signal.

主权项

1. A circuit for controlling an RF generator, the circuit comprising:
a first heterodyne stage receiving an input signal, the input signal being based on a characteristic of an RF signal generated by the RF generator, with the first heterodyne stage configured to:
mix the input signal with a first mix signal to generate a first heterodyne signal; andfilter the first heterodyne signal through a low pass filter; a second heterodyne stage receiving the filtered first heterodyne signal, the second heterodyne stage configured to:
mix the filtered first heterodyne signal with a second mix signal to generate a second heterodyne signal; andfilter the second heterodyne signal through a band pass filter; a detection stage configured to convert the filtered second heterodyne signal to a DC signal; and a power control stage receiving the DC signal and configured to control the RF signal in response to the DC signal.