Patent EP0099703A2 successfully refreshed from Google Patents.
EP0099703A2
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An envelope detector
Assignee: Fujitsu Ltd
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Filing: 1983-07-07
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Granted: —
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Expires: 2003-07-07
Abstract
Abstract In an envelope detector, signal divider means (9) divide an input signal into a pair of output signals of equal amplitude and equal phase. A reference oscillator (5, 6) provides a pair of reference signals of equal amplitude of phases differing by 90°. In modulating means (7, 7') each output signal is modulated by a respective reference signal to provide modulated signals which are filtered by respective low pass filters (11, 11') to provide base band signals. The base band signals are squared by squaring circuits (12, 12') and the resulting signals added by an adder circuit (13). The square root of the sum may be provided by a square root circuit (14). Alternatively, the base band signals are delivered to absoluting circuits (15, 15') to provide their absolute values which are added in an adder circuit (13).
Inventors
- 👤 Tokihiro Miyo
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 15:52
CPC Classifications
H; H03; H03D; H03D1/00; H03D1/22
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
279 words
An envelope detector for detecting the amplitude envelope of an input signal, comprising: a) signal divider means arranged for receiving the input signal and operable to divide the input signal into first and second output signals, of equal power; b) reference oscillator means operable to provide first and second reference frequency signals, of frequency substantially the same as that of the input signal, of equal power; c) first and second modulator means, each having first and second inputs and an output, the first and the second inputs of the first modulator means being connected to receive the first output signal and the first reference frequency signal respectively, the first and the second inputs of the second modulator means being connected to receive the second output signal and the second reference frequency signal respectively, whereby the first and second modulator means provide respectively at their outputs a first modulated signal, based on the first output signal and the first reference frequency signal, and a second modulated signal based on the second output signal and the second reference frequency signal; d) first and second low pass filters operatively connected to the outputs of the first and second modulator means respectively, for filtering harmonic frequency components from the first and second modulated signals, to provide first and second base band signals respectively, the detector being such that the first and second base band signals differ in phase by 90 0 ; and e) a full wave rectifying means operatively connected to said first and second low pass filters, to receive the said first and second base band signals, operable to provide a signal proportional to the amplitude envelope of the input signal.
Claim 2
Dependent Claim
279 words
An envelope detector for detecting the amplitude envelope of an input signal, comprising: a) signal divider means arranged for receiving the input signal and operable to divide the input signal into first and second output signals, of equal power; b) reference oscillator means operable to provide first and second reference frequency signals, of frequency substantially the same as that of the input signal, of equal power; c) first and second modulator means, each having first and second inputs and an output, the first and the second inputs of the first modulator means being connected to receive the first output signal and the first reference frequency signal respectively, the first and the second inputs of the second modulator means being connected to receive the second output signal and the second reference frequency signal respectively, whereby the first and second modulator means provide respectively at their outputs a first modulated signal, based on the first output signal and the first reference frequency signal, and a second modulated signal based on the second output signal and the second reference frequency signal; d) first and second low pass filters operatively connected to the outputs of the first and second modulator means respectively, for filtering harmonic frequency components from the first and second modulated signals, to provide first and second base band signals respectively, the detector being such that the first and second base band signals differ in phase by 90 0 ; and e) a full wave rectifying means operatively connected to said first and second low pass filters, to receive the said first and second base band signals, operable to provide a signal proportional to the amplitude envelope of the input signal.
Claim 3
Dependent Claim
38 words
An envelope detector as claimed in claim 1, wherein the signal divider provides the first and second output signals with equal phase, and the reference oscillator provides the first and second reference signals with phases differing by 90°.
Claim 4
Dependent Claim
85 words
An envelope detector as claimed in claim 1 or 2, wherein the full wave rectifying means comprises: first and second squaring circuits operatively connected to the first and the second low pass filters respectively to receive the first and second base band signals, to provide first and the second squared signals respectively; and an adder circuit connected to said first and second squaring circuits to receive the first and second squared signals, operable to provide a sum signal of the first and second squared signals.
Claim 5
Dependent Claim
47 words
An envelope detector as claimed in claim 3, further comprising a square root circuit operatively connected to said adder circuit to receive the sum signal from said adder circuit, operable to provide a signal proportional to the envelope of the amplitude of the input analog carrier signal.
Claim 6
Dependent Claim
80 words
An envelope detector as claimed in claim 1 or 2, wherein the full wave rectifying means comprises: first and second absoluting circuits, operatively connected respectively to said first and second low pass filters to receive the first and the second base band signals, operable to provide first and second absolute value Signals respectively; and an adder circuit operatively connected to said first and second absoluting circuits, operable to provide a sum signal of the first and second absolute value signals.
Claim 7
Dependent Claim
26 words
An envelope detector as claimed in claim 1, 2, 3, 4 or 5, wherein said first and second modulator means are of a double balanced type.
Claim 8
Dependent Claim
17 words
An envelope detector as claimed in any preceding claim, wherein the signal divider comprises hybrid circuit means.
Claim 9
Dependent Claim
22 words
An envelope detector as claimed in any preceding claim, adapted for envelope detection in respect of an analog carrier wave input signal.
References Cited (Backward Citations)
No citation records indexed.
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