Patent EP0198162A1 successfully refreshed from Google Patents.
EP0198162A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Frequency converter used for a receiver which receives signals of a UHF band or a microwave band
Assignee: Hitachi Ltd
•
Filing: 1986-02-05
•
Granted: —
•
Expires: 2006-02-05
Abstract
Abstract @ A frequency converter which is capable of rejecting unnecessary signal generated by image signals. The frequency converter has first and second local oscillation circuits (1, 2) which generate local oscillation signals whose frequencies are the same and whose phases are different by 90 degrees from each other, has two mixer circuits (7, 8), and has a hybrid coupler (9). The mixer circuits (7, 8) generate two unnesserary signals whose phases are different by 90 degrees from each other. The hybrid coupler (9) delays one unnecessary signal by a quarter of the wavelength to generate two unnecessary signals whose phases are different by 180 degrees from each other, so that they are cancelled by each other.
Inventors
- 👤 Hiroyuki Mizukami
- 👤 Masaki Noda
- 👤 Toshio Nagashima
- 👤 Keiro Shinkawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 08:12
CPC Classifications
H; H03; H03D; H03D7/00; H03D7/16; H03D7/165; H03D7/18
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
478 words
A frequency converter comprising: a) a signal divider which has an input terminal to which will be input an input signal that contains a main signal and an image signal, and which divides the input signal supplied to said input terminal into a first divided input signal and a second divided input signal; b) a first local oscillation signal generator circuit which has a frequency control terminal that is served with a channel select voltage, and a first voltage-controlled oscillator which generates a first local oscillation signal whose oscillation frequency changes depending upon the channel select voltage supplied to said frequency control terminal; c) a second local oscillation signal generator circuit which generates a second local oscillation signal, the frequency of said second local oscillation signal being equal to the frequency of the first local oscillation signal generated by said first local oscillation signal generator circuit, and the phase of the second local oscillation signal being different by 90 degrees from the phase of the first local oscillation signal; d) a first mixer circuit which is connected to said signal divider and to said first local oscillation signal generator circuit, which is served with the first divided input signal from said signal divider and with the first local oscillation signal from said first local oscillation signal generator, and which generates a first intermediate-frequency signal of a wavelength X that contains a first necessary signal obtained from the main signal and a first unnecessary signal obtained from the image signal, responsive to the first divided input signal and the first local oscillation signal; e) a second mixer circuit which is connected to said signal divider and to said second local oscillation signal generator circuit, which is served with the second divided input signal from said signal divider and with the second local oscillation signal from said second local oscillation signal generator, and which generates a second intermediate-frequency signal of a wavelength X that contains a second necessary signal obtained from the main signal and a second unnecessary signal obtained from the image signal, responsive to the second divided input signal and the second local oscillation signal; and f) a hybrid coupler which is connected to said first and second mixer circuits, which is served with the first intermediate-frequency signal from said first mixer circuit and with the second intermediate-frequency signal from said second mixer circuit, which has at least one output terminal, which supplies the first intermediate-frequency signal to the output terminal thereof, and which supplies the second intermediate-frequency signal to the output terminal thereof, the second intermediate-frequency signal being delayed by a quarter of the wavelength (1 4λ) behind the first intermediate-frequency signal, such that the phase of the first unnecessary signal is different by 180 degrees from the phase of the second unnecessary signal, and that the first and second unnecessary signals are cancelled by each other.
Claim 2
Dependent Claim
478 words
A frequency converter comprising: a) a signal divider which has an input terminal to which will be input an input signal that contains a main signal and an image signal, and which divides the input signal supplied to said input terminal into a first divided input signal and a second divided input signal; b) a first local oscillation signal generator circuit which has a frequency control terminal that is served with a channel select voltage, and a first voltage-controlled oscillator which generates a first local oscillation signal whose oscillation frequency changes depending upon the channel select voltage supplied to said frequency control terminal; c) a second local oscillation signal generator circuit which generates a second local oscillation signal, the frequency of said second local oscillation signal being equal to the frequency of the first local oscillation signal generated by said first local oscillation signal generator circuit, and the phase of the second local oscillation signal being different by 90 degrees from the phase of the first local oscillation signal; d) a first mixer circuit which is connected to said signal divider and to said first local oscillation signal generator circuit, which is served with the first divided input signal from said signal divider and with the first local oscillation signal from said first local oscillation signal generator, and which generates a first intermediate-frequency signal of a wavelength X that contains a first necessary signal obtained from the main signal and a first unnecessary signal obtained from the image signal, responsive to the first divided input signal and the first local oscillation signal; e) a second mixer circuit which is connected to said signal divider and to said second local oscillation signal generator circuit, which is served with the second divided input signal from said signal divider and with the second local oscillation signal from said second local oscillation signal generator, and which generates a second intermediate-frequency signal of a wavelength X that contains a second necessary signal obtained from the main signal and a second unnecessary signal obtained from the image signal, responsive to the second divided input signal and the second local oscillation signal; and f) a hybrid coupler which is connected to said first and second mixer circuits, which is served with the first intermediate-frequency signal from said first mixer circuit and with the second intermediate-frequency signal from said second mixer circuit, which has at least one output terminal, which supplies the first intermediate-frequency signal to the output terminal thereof, and which supplies the second intermediate-frequency signal to the output terminal thereof, the second intermediate-frequency signal being delayed by a quarter of the wavelength (1 4λ) behind the first intermediate-frequency signal, such that the phase of the first unnecessary signal is different by 180 degrees from the phase of the second unnecessary signal, and that the first and second unnecessary signals are cancelled by each other.
Claim 3
Dependent Claim
154 words
A frequency converter according to claim 1, wherein said second local oscillation signal generator circuit is comprised of: a second voltage-controlled oscillator which is served with the channel select voltage from said frequency control terminal, and which generates a second local oscillation signal whose oscillation frequency changes depending upon the channel select voltage; a phase detector which is served with the first local oscillation signal from the first voltage-controlled oscillator, and with the second local oscillation signal from the second voltage-controlled oscillator, which compares.the phase of the first local oscillation signal with the phase of the second local oscillation signal, and which generates a phase error signal; a loop filter which is connected to the phase detector and is served with the phase error signal from the phase detector; and an adder which is connected to the loop filter and which adds the output signal of the loop filter to the channel select voltage.
Claim 4
Dependent Claim
37 words
A frequency converter according to claim 1, wherein the signal divider has a first transformer and a second transformer that are connected in series with each other, and the second transformer is connected to said input terminal.
Claim 5
Dependent Claim
99 words
A frequency converter according to claim 1, wherein the hybrid coupler is constituted by a surface acoustic wave filter which consists of a first input electrode, a second input electrode, and an output electrode, and which propagates elastic waves, and wherein the first input electrode is connected to the first mixer circuit, the second input electrode is connected to the second mixer circuit, and the distance between the second input electrode and the output electrode is greater than the distance between the first input electrode and the output electrode by a quarter of the wavelength of the elastic wave.
Claim 6
Dependent Claim
156 words
A frequency converter according to claim 4, wherein said second local oscillation signal generator circuit is comprised of: a second voltage-controlled oscillator which is served with the channel select voltage from said frequency control terminal, and which generates a second local oscillation signal whose oscillation frequency changes depending upon the channel select voltage; a phase detector which is served with the first local oscillation signal from the first voltage-controlled oscillator, and with the second local oscillation signal from the second voltage-controlled oscillator, which compares the phase of the first local oscillation signal with the phase of the second local oscillation signal, and which generates a phase error signal; a loop filter which is connected to the phase detector and is served with the phase error signal from the phase detector; and an adder which is connected to the loop filter and which adds the output signal of the loop filter filter to the channel select voltage.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.