Voltage controlled oscillator

Abstract

The invention discloses a voltage controlled oscillator, which comprises a bipolar voltage controlled oscillator unit and an output buffer unit, wherein the bipolar voltage controlled oscillator unit has a difference structure and comprises an LC resonant circuit module and a negative resistance circuit module; the LC resonant circuit module is used for generating first oscillation signals of the needed oscillation frequency; the negative resistance circuit module comprises a pair of first bipolar transistors; the output buffer unit comprises two second bipolar transistors; bases of the two second bipolar transistors are respectively connected with a first output port of the LC resonant circuit module; and emitters of the two second bipolar transistors serve as two second output ports of the voltage controlled oscillator and output differential pairs of second oscillation signals. Power of the oscillation signals can be improved, phase noise of the circuit can be reduced in the condition of not changing the oscillation frequency of the oscillation signals, and online test can be carried out on radio frequency parameters of the oscillation signals on a radio frequency probe table.

Description

technical field [0001] The invention relates to a semiconductor integrated circuit, in particular to a voltage-controlled oscillator. Background technique [0002] An oscillator is a circuit that converts DC power energy into AC energy. In order to be able to generate a self-sustaining output oscillating signal, that is, a radio frequency signal, without an external input signal, the oscillator itself must have positive feedback and sufficient gain to overcome the loss on the feedback path, and a frequency-selective network is also required. [0003] Many applications require that the frequency of the oscillator is a function of the control voltage and is adjustable, and the voltage-controlled oscillator meets this requirement, such as figure 1 Shown is a circuit structure diagram of an existing voltage-controlled oscillator; the existing voltage-controlled oscillator includes: [0004] The LC resonant circuit module is used to generate an oscillating signal of a required ...

AI Technical Summary

Problems solved by technology

[0008] Measuring the performance of a voltage controlled oscillator mainly includes the following parameters: center frequency (center frequency), tuning range (tuning range), tuning linearity ( tuninglinearity), output amplitude (outputamplitude), phase noise (phasenoise), power supply and common-mode rejection ratio (supplyandcommon-moderejection), power consumption (powerdissipation), etc., in order to accurately test the above RF parameters, it is usually designed to be in On-line test on the RF probe station, but because the output amplitude of the oscillator with a higher frequency is small, sometimes the oscillation signal cannot be tested

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