Hangzhou Geo-chip Technology Co., Ltd.

Ruili Wu

Chun Geik Tan

Yanping Zhou

Yang Yang

Sy-Chyuan Hwu

The present disclosure provides a phase-locked loop, a frequency divider and a communication device that enable fast locking. The phase-locked loop comprises a phase frequency detector, a charge pump, a loop filter, a voltage-controlled oscillator, a fast-locking control unit and a frequency divider, wherein the frequency divider comprises a plurality of cascaded frequency division units and a reset/set control circuit, the reset/set control circuit being configured to receive the reset signal outputted by the fast-locking control unit, and in response to transition of the reset signal from a low level to the high level, change a state code combination composed of respective state codes of the cascaded frequency division units from the first state to the second state, to cause transition of a feedback signal outputted by the frequency divider from the low level to the high level. With the frequency divider and phase-locked loop, fast locking can be achieved.

Fast-locking phase-locked loop, frequency divider, and communication device

Disclosed are a receiver and a zero-IF transceiver. The receiver includes a frequency mixer circuit including two mixers in parallel and weighted feedback circuits respectively corresponding to the mixers, each mixer having an output end connected to an input end of the corresponding weighted feedback circuit, and each weighted feedback circuit having an output end connected to an input end of the other weighted feedback circuit. Each mixer is configured to receive a baseband signal, mix the baseband signal, and input the resulting mixed signal to the corresponding weighted feedback circuit; and each weighted feedback circuit is configured to receive the mixed signal from the corresponding mixer, and adjust the received mixed signal using complex impedance-based feedback to compensate for an asymmetric frequency response in a wideband zero-IF receiver. Weighted feedback circuits are utilized for adjustments using complex impedance-based feedbacks, thereby alleviating quadrature imbalance and reducing power consumption and cost.

Receiver and zero-intermediate frequency transceiver

An operational amplifier, any of a pair of amplification circuits of its output-stage amplification circuit unit comprises: a first and second transistors, a capacitor and a DC bias circuit; a control electrode of the first transistor is connected with a corresponding output terminal of a preceding-stage amplification circuit unit, a first electrode thereof is connected with a first power terminal and a second electrode thereof is connected with an output terminal of an amplification circuit of the output-stage amplification circuit unit; an output terminal of the DC bias circuit is connected with a control electrode of the second transistor, a first electrode of which is connected with a second power terminal, and a second electrode thereof is connected with the output terminal; both ends of the capacitor are respectively connected with the control electrodes of the first and second transistors; and the first and second transistors are of opposite polarities.

Operational amplifier and electronic system

The present disclosure relates to a fractional frequency divider, a radio frequency transceiver, and a method of configuring a phase delay in the fractional frequency divider. The fractional frequency divider comprises a counter, a multiplexer, and a delay module. The method is applicable to the fractional frequency divider. The radio frequency transceiver comprises the fractional frequency divider, and the fractional frequency divider adopts the method. According to the aforesaid technical solution, the present disclosure has advantages as follows: the embodiments of the present disclosure can minimize the timing inaccuracy and suppress the output jitter and output spurs; and the embodiments of the present disclosure can effectively extend the operating frequency range of the fractional frequency divider.

Growing community of inventors

Hangzhou, China

Ruili Wu