EP0149319A2
Expired / Lapsed
EP
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High frequency circuit
Assignee: BAE Systems Electronics Ltd
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Filing: 1984-11-26
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Granted: —
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Expires: 2004-11-26
Abstract
Abstract A high frequency circuit is arranged to modify a signal, such as a television broadcast signal, prior to high power amplification so as to compensate for distortions introduced by the amplifier. Separate signal paths give independent adjustment of the differential gain, differential phase and linearity of the signal by altering the characteristics of level dependent detectors.
Inventors
- 👤 Melvyn Mcgann
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 14:08
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/22; H03F; H03F1/00; H03F1/32; H03F1/3241; H03F1/3276; H03G3/30; H03G3/3036; H03G3/3042; H04; H04N; H04N5/00; H04N5/38
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
99 words
1 . A high frequency correction circuit including means for receiving a wideband high frequency signal, and for routing it via a delay device to an amplitude modulator; a level dependent detector to which the received signal is applied, and which modifies the amplitude of the signal in a manner which is itself dependent upon the amplitude; a broadband 90° phase shifter arranged to receive the amplitude modified signal and the output of which is fed to the amplitude modulator so as to adjust the phase of said received signal which is routed to it via the delay device.
Claim 2
Dependent Claim
99 words
1 . A high frequency correction circuit including means for receiving a wideband high frequency signal, and for routing it via a delay device to an amplitude modulator; a level dependent detector to which the received signal is applied, and which modifies the amplitude of the signal in a manner which is itself dependent upon the amplitude; a broadband 90° phase shifter arranged to receive the amplitude modified signal and the output of which is fed to the amplitude modulator so as to adjust the phase of said received signal which is routed to it via the delay device.
Claim 3
Dependent Claim
56 words
A circuit as claimed in claim 1 and wherein a further level dependent detector is provided in parallel with the first mentioned level dependent detector, with the output of the further detector being fed into the modulation input port of the amplitude modulator, either directly or after combination with the output signal of said phase comparator.
Claim 4
Dependent Claim
25 words
A circuit as claimed in claim 1 or 2 and wherein a bandpass filter is provided in the output path of each level dependent detector.
Claim 5
Dependent Claim
47 words
A circuit as claimed in claim 1 or 2 and wherein an additional level dependent detector is provided in parallel with the first and second mentioned level dependent detectors, with the output of the additional detector being fed via a low pass filter to the amplitude modulator.
Claim 6
Dependent Claim
40 words
A circuit as claimed in any of the preceding claims, and wherein each level dependent detector includes a plurality of voltage sources, each arranged to bias a respective diode into conduction in dependence on the level of the input signal.
Claim 7
Dependent Claim
34 words
A circuit as claimed in claim 5 and wherein each level dependent detector includes a transistor, with the current flow through the transistor being dependent on the number of associated diodes which are conductive.
References Cited (Backward Citations)
No citation records indexed.
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