Signal processing circuit, has divider circuit with output to direct signal with phase offset of ninety degree to another signal at other output of divider circuit, and feedback path placed between input of divider circuit and mixer output

摘要

The circuit has an oscillator connected with inputs of two mixers (3, 4). Output (33) of the mixer (3) is coupled with a frequency divider circuit (2). The circuit (2) has an output (22) coupled with an input (32) of the mixer (3), and an output (23) to direct a signal with a phase offset of 90 degree to another signal at the output (22). A feedback path is provided between an input (21) of the circuit (2) and the output (33). The circuit (2) is implemented with a sigma delta modulator for producing signals with broken divisor conditions. The signal at the output (22) is supplied to another input (42) of the mixer (4).