EP0227015A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Diversity receiving system of In-Phase Combination Type
Assignee: NEC Corp
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Filing: 1986-12-16
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Granted: —
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Expires: 2006-12-16
Abstract
Abstract The invention relates to a space diversity receiving system which combines under in-phase state carrier waves received by a plurality of antennae. The system comprises a local oscillator (9), first and second frequency converters (7, 8), an endless phase shifter (10), a combiner (11), an automatic gain controlled IF amplifier (12), a level detector (1), a memory (3), a comparator (2), a decision unit (4), a sign discriminator (5), and a phase shifter controller (6) for controlling said endless phase shifter (10). The system provides a lower error rate of received signals and high reliability of the communication line.
Inventors
- 👤 Shigeru Takahara
- 👤 Masaharu Morisaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 20:34
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/02; H04B7/04; H04B7/08; H04B7/0837; H04B7/084
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
323 words
An in-phase combination type of diversity receiving system comprising: a local oscillator; a first frequency converter for converting a first signal to a first IF signal by the output of said local oscillator; an endless phase shifter for adjusting a phase of the output of said local oscillator in response to a phase control signal; a second frequency converter for converting a second signal to a second IF signal by the output of said endless phase shifter; a combiner for combining said first and second IF signals; an automatic gain controlled IF amplifier for amplifying the output of said combiner; a level detector for detecting an AGC voltage of said IF amplifier; a memory for storing the output of said combination level detector; a comparator for comparing an output of said combination level detector which appears when said endless phase shifter is rotated by a predetermined phase amount and an output of said memory which stores an output of said combination level detector which appeared before said adjustment of said endless phase shifter and, thereby, producing an absolute value and a polarity of a difference between said two outputs; a decision unit for deciding whether said absolute value is greater than a predetermined value; a sign discriminator for, when said absolute value is greater than said predetermined value, discriminating a polarity of said difference; and a phase shifter controller constructed to, when said absolute value is not greater than said predetermined value, shift said endless phase shifter by another predetermined phase amount and, when said absolute value is greater than said predetermined value, to store said output of said level detector and, based on said polarity which is determined by said sign discriminator, to shift said endless phase shifter by said predetermined phase amount in the same or the opposite direction in response to the output of the sign discriminator, whereby said first and second signal are combined in the vicinity of in-phase.
Claim 2
Dependent Claim
323 words
An in-phase combination type of diversity receiving system comprising: a local oscillator; a first frequency converter for converting a first signal to a first IF signal by the output of said local oscillator; an endless phase shifter for adjusting a phase of the output of said local oscillator in response to a phase control signal; a second frequency converter for converting a second signal to a second IF signal by the output of said endless phase shifter; a combiner for combining said first and second IF signals; an automatic gain controlled IF amplifier for amplifying the output of said combiner; a level detector for detecting an AGC voltage of said IF amplifier; a memory for storing the output of said combination level detector; a comparator for comparing an output of said combination level detector which appears when said endless phase shifter is rotated by a predetermined phase amount and an output of said memory which stores an output of said combination level detector which appeared before said adjustment of said endless phase shifter and, thereby, producing an absolute value and a polarity of a difference between said two outputs; a decision unit for deciding whether said absolute value is greater than a predetermined value; a sign discriminator for, when said absolute value is greater than said predetermined value, discriminating a polarity of said difference; and a phase shifter controller constructed to, when said absolute value is not greater than said predetermined value, shift said endless phase shifter by another predetermined phase amount and, when said absolute value is greater than said predetermined value, to store said output of said level detector and, based on said polarity which is determined by said sign discriminator, to shift said endless phase shifter by said predetermined phase amount in the same or the opposite direction in response to the output of the sign discriminator, whereby said first and second signal are combined in the vicinity of in-phase.
References Cited (Backward Citations)
No citation records indexed.
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