JPH10313219A - Frequency converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the fluctuation of impedance and the insertion loss in the case that a phase is fluctuated when the output phase of an output signal of the frequency converter is all changed. SOLUTION: When an RF frequency of the frequency converter is higher than a local oscillation (Lo) frequency, a simple 180 deg. phase shifter 1 (2) is connected to an RF (Lo) port, and the phase is shifted entirely by using it that the phase shifters of the RF and Lo ports shift a phase of an output signal opposite to each other in one operation, and then the 180 deg. phase shifters reduce the fluctuation in impedance and insertion loss.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency converter, and more particularly to a frequency converter capable of changing the entire phase by using two 180 ° phase shifters.

[0002]

2. Description of the Related Art As shown in FIG. 1, a conventional frequency converter converts an RF frequency and a local oscillation frequency (Lo) into a mixer 3.
In order to change the output signal phase of the frequency converter when mixing and converting to the intermediate frequency (IF) by using
Port, IF port, or Lo port. In the example of FIG. 1, the phase shifter 5 is provided at the RF port.

[0003]

In the conventional frequency converter, it is difficult to change the entire phase of 360 ° with one phase shifter. The reason is that if the phase is largely changed by one phase shifter, the impedance and the passing loss of the phase shifter will fluctuate greatly.

An object of the present invention is to provide a simpler circuit configuration.
An object of the present invention is to provide a frequency converter capable of performing a phase change of all phases using an 80 ° phase shifter.

[0005]

According to the present invention, only when the RF frequency of the frequency converter is higher than the local oscillation frequency,
Using the fact that the 180 ° phase shifter provided at the Lo port moves in the same phase and the opposite phase as the 180 ° phase shifter provided at the RF port, two phase shifters of the RF port and the Lo port are used.
All phases can be changed.

That is, the present invention relates to a frequency converter for mixing an RF frequency and a local oscillation frequency to convert the mixed frequency into an intermediate frequency, wherein a first 180 ° phase shifter provided at a port to which the RF frequency is input; A second 180 ° phase shifter provided at a port to which the local oscillation frequency is input.

[0007]

FIG. 2 shows an embodiment of the frequency converter according to the present invention. This frequency converter has an RF port, Lo
Mixer 3 having a port and an IF port, a 180 ° phase shifter 1 provided at an RF port, and a 180 ° phase shifter 1 provided at a Lo port.
And 相 phase shifter 2.

In this phase shifter, since the RF frequency is higher than the local oscillation frequency, the IF port output by the same operation of the 180 ° phase shifter 1 of the RF port and the 180 ° phase shifter 2 of the Lo port is output. Signals move in opposite phases.

FIG. 3 shows the phase characteristics of the IF output. RF
It will be appreciated that the 180 ° phase shifter 1 at the port and the 180 ° phase shifter 2 at the Lo port can move all phases.

[0010]

According to the frequency converter of the present invention, the change in impedance and the change in passing loss due to the phase shifter are reduced. The reason is that a 180 ° phase shifter having a simpler circuit is used instead of a phase shifter that changes the entire phase.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conventional frequency converter.

FIG. 2 is a diagram showing a frequency converter of the present invention.

FIG. 3 is a phase characteristic of an IF output of the frequency converter of FIG. 2;

[Explanation of symbols]

 1 phase shifter (RF port side) 2 phase shifter (Lo port side) 3 mixer

Claims (4)

[Claims] 1. A frequency converter characterized in that the output signal phase can be changed in all phases by using two 180 ° phase shifters. 2. A mixer, a first 180 ° phase shifter provided at a first input port of the mixer, and a second 180 ° phase shifter provided at a second input port of the mixer. A frequency converter comprising: 3. A frequency converter for mixing an RF frequency and a local oscillation frequency to convert the mixed frequency into an intermediate frequency, wherein said first frequency converter is provided at a port for inputting an RF frequency.
A frequency converter comprising: a 0 ° phase shifter; and a second 180 ° phase shifter provided at a port to which a local oscillation frequency is input. 4. The frequency converter according to claim 3, wherein the RF frequency is higher than the local oscillation frequency.