SU1417170A1 - Frequency converter - Google Patents

Abstract

The invention relates to radio engineering. The purpose of the invention is to increase the transmission coefficient and improve the distribution of the intermediate frequency signal. The frequency converter contains a mixer 1, a source of 2 local oscillator signals, a coupling capacitor (RC) 3, a low-pass filter (LPF) 4. Parallel to the output of source 2 of the heterodyne signal, a quarter-wave short-circuited loop 5 is connected, and a coil is inserted between the LPF output and the common bus 6 agility. The intermediate frequency signal is filtered out and with minimal loss arrives at the output of the frequency converter due to the fact that RC 3 and inductor 6 form a resonant circuit for which the parallel resonance condition is satisfied. 1 il.

Description

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The invention relates to radio engineering and can be used in various radio devices containing harmonic mixers.

The purpose of the invention is to increase the transmission coefficient and improve the selection of the intermediate frequency signal.

The drawing shows an electric system functional diagram of the frequency converter.

The frequency converter contains a mixer J, a source 2 signal of the local oscillator, a separation capacitor 3, a low-pass filter 4 (LPF), a quarter-wave short-circuit loop cable 5 and an inductance coil 6.

The frequency converter operates as follows.

The local oscillator signal from the source 2 output of the local oscillator signal is fed to the mixer I via coupling capacitor 3. For coupling capacitor 3, the condition

.i (2ff, .er С, t,

where Zo is the characteristic impedance

microstrip transmission line in the local oscillator channel and the first input; f gwt average frequency

heterodyne; С - separating capacity

capacitor 3 ,.

as a result, the signal of the source 2 heterodyne without loss enters the mixer 1 through the first input. The loss of the source 2 heterodyne signal to a branch to the intermediate frequency channel does not occur as a result of the presence of low-pass filters 4, the input resistance of which is from the input side for a signal with a frequency c (gel is large.

The intermediate frequency signal, f}, is filtered out and with minimal losses, is set to on, the output of the frequency converter is due to this.

Editor A. Lezhnin

Compiled by A. Menshikov Tehred M. Khodanych

Order 4077/56

Circulation 928

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, F-33, Raushsk nab., 4/5

that separation capacitor 3 and inductance coil 6 form on f, 2 a resonant circuit connected in parallel to the output of mixer I and the output of the frequency converter, for which the parallel resonance condition is satisfied

(.Г „,) L, C,,

where Cj is the capacitance of separation capacitor 3,

LJ - inductance of coil 6 inductance.

The second terminal of the coupling capacitor 3 is connected to the housing via a short-circuited loop 5, which is a short circuit for the signal / intermediate frequency G ". At the same time, for the signal of the source 2 signal of the local oscillator on the input side of the low-pass filter 4, the input resistance of the short-circuited quarter-wave loop 5 is large, since its equivalent electrical length is chosen equal to .zei. D cpt "r is the average frequency of the local oscillator signal source.

Claims (1)

Formula of the invention A frequency converter containing a mixer, the first input of which is an input signal input, and the second input is connected via a coupling capacitor to the output of a local oscillator signal source, as well as a low-pass filter whose input is connected to the mixer output, and the output is a frequency converter output different in order to increase the transmission coefficient and. improving the selection of the intermediate frequency signal, parallel to the output of the local oscillator signal source, a quarter-wave short-circuit loop is connected, and an inductance coil is inserted between the output of the low-pass filter and the common bus. Proofreader M. Demchik Subscription