KR930022747A - Low noise down frequency converter - Google Patents

Abstract

The present invention uses a dual gate field effect transistor (dual gate MESFET) in a low-noise down-frequency converter to simultaneously convert the local oscillation and frequency mixing to convert the high frequency into an intermediate frequency that can be received as a video and audio signal The present invention relates to a self-oscillating oscillation circuit which is connected between a band pass filter and a low pass filter to achieve its own high frequency oscillation, and simultaneously mixes the input high frequency and the self oscillating frequency, and removes the unwanted wave to generate a stable intermediate frequency. With the furnace, the input high frequency signal can realize the self oscillation and mixing process simultaneously without affecting each other, and also obtain the stable intermediate frequency by eliminating the high frequency generated in the frequency mixing process, and also the low noise down frequency due to the simple configuration. Contributes to miniaturization of transducers It would be a help.

Description

Low noise down frequency converter

Since this is an open matter, no full text was included.

1 is a block diagram of a conventional low noise downlink frequency converter.

2 is a block diagram of a low noise downlink frequency converter of the present invention.

3 is a self-oscillating mixer circuit according to the present invention.

Claims (4)

A first amplifier for three-stage low noise amplification of the input high frequency signal, a band pass filter for passing the output frequency only through a specific band, a low pass filter for passing the input intermediate frequency only through a specific band, and an intermediate frequency at a constant level A low noise down-frequency converter including a second amplifier for controlling gain, the low-pass frequency converter is connected between the band pass filter and the low pass filter so as to achieve its own high frequency oscillation, and simultaneously the mixing of the input high frequency and the self oscillation frequency And a low noise down frequency converter with a self-oscillating mixer circuit that generates a stable intermediate frequency by removing unwanted waves. 2. The self-oscillating mixer circuit according to claim 1, wherein the self-oscillating mixer circuit comprises a dielectric known oscillator which is a self-oscillating element of the first gate end of the field effect transistor, and an impedance match connected to the second gate end, the drain and the source end of the field effect transistor, respectively. First to third microstrip transmissions, first and second undesired noise cancelers connected to the first and second microstrip transmission lines to remove unnecessary frequencies, and connected to the field effect transistor drain terminal and mixed with frequency. A low noise town downlink frequency converter including a third unnecessary wave removing unit for removing a high frequency signal generated during the operation. The self-oscillating mixer circuit according to claim 2, wherein the field effect transistor uses a dual gate gallium arsenide field effect transistor. 3. The self-oscillating mixer circuit according to claim 2, wherein the first to third unwanted wave removing units are? / 4 micro strip transmission lines. ※ Note: The disclosure is based on the initial application.