Mixer circuit, receiver circuit, and frequency comparison circuit

Abstract

A mixer circuit contains a first terminal and a second terminal to which a first differential input signal is applied, and an active element switching a short-circuit between the first terminal and the second terminal. By driving the active element by a second differential input signal having a predetermined frequency, the first terminal and the second terminal are intermittently short-circuited at twice the frequency of a predetermined frequency.

1 . A polyphase oscillation circuit, comprising: 
 a plurality of Colpitts circuits; and    a plurality of capacities,    wherein each of said Colpitts circuits and each of said capacities are alternately aligned and said Colpitts circuits are connected to form a loop via said capacities.    
   
   
       2 . The polyphase oscillation circuit as claimed in  claim 1 , wherein each of said Colpitts circuits contains a transistor and a control end of said transistor is connected to a bias voltage.  
   
   
       3 . The polyphase oscillation circuit as claimed in  claim 2 , further comprising a resistor connected to each said control end of said transistors of said Colpitts circuits, wherein said bias voltage is supplied to each said control end via said resistor.