Communication circuit and associated calibration method

摘要

A communication circuit includes a receiver path, a frequency translating loop filter and a signal source circuit. The frequency translating loop filter includes an auxiliary mixer, and a frequency translating filter backend circuit such as a filter. The signal source circuit can be shared with a transmitter path. When the receiver path receives an external signal, the auxiliary mixer and the frequency translating filter backend circuit perform high-frequency filtering. When the receiver path need not receive the external signal, the auxiliary mixer up-converts a low-frequency auxiliary signal provided by the signal source circuit to a high-frequency domain, and the up-converted signal is received by the receiver path. Thus, an operation parameter of the receiver path can be adjusted and calibrated according to a response of the receiver path.

主权项

1. A communication circuit, comprising:
a receiver path, comprising:
an input port; anda reception mixer, coupled to the input port, configured to mix a signal of the input port with a reception oscillation frequency; and a signal source circuit; and an auxiliary mixer, coupled between the input port and the signal source circuit, operable in an auxiliary mode; wherein, when the auxiliary mixer operates in the auxiliary mode, the signal source circuit provides an auxiliary signal, and the auxiliary mixer mixes the auxiliary signal with the reception oscillation frequency and sends a mixed result to the input port, wherein the auxiliary mixer is further operable in a reception mode; when the auxiliary mixer operates in the reception mode, the auxiliary mixer is configured to co-operate with a frequency translating filter backend circuit to filter the signal of the input port, the communication circuit further comprising: a switch circuit, coupled between the frequency translating filter backend circuit, the signal source circuit and the auxiliary mixer; wherein, when the auxiliary mixer operates in the auxiliary mode, the switch circuit conducts the signal source circuit to the auxiliary mixer; when the auxiliary mixer operates in the reception mode, the switch circuit conducts the frequency translating filter backend circuit to the auxiliary mixer.