Patent US3899738A successfully refreshed from Google Patents.
US3899738A
Expired / Lapsed
US
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System for measuring group delay and/or attenuation in closed signal-transmission loop
Assignee: Wandel and Golterman GmbH and Co
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Filing: 1974-08-08
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Granted: 1975-08-12
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Expires: 1994-08-08
Abstract
Abstract Several measuring stations are linked with one another by line segments enabling signal transmission thereover in a closed loop, each station including a receiving section and a transmitting section. A selector switch in the transmitting section enables establishment of a first position (I) for sending out signals originating at that section, a second position (II) for retransmitting an incoming modulating frequency (f3), and a third position (III) for transmitting a replica of an incoming modulated carrier wave.
Inventors
- 👤 Peter Harzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:38
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/46; H04B3/462
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
268 words
A system for sending amplitude-modulated carrier waves over transmission paths linking a plurality of measuring stations in a closed loop, said stations serving to determine the characteristics of said transmission paths, comprising: a receiving section and a transmitting section at each measuring station; a wave synthesizer in said transmitting section including oscillation-generating means for producing separate highfrequency carrier oscillations and low-frequency modulating oscillations, said wave synthesizer further including modulating means for combining said oscillations into an outgoing amplitude-modulated carrier wave; processing means in said receiving section for isolating a carrier component and a modulating component of an incoming amplitude-modulated carrier wave, said processing means including output circuitry producing signal voltages derived from at least one of said components; evaluation means in said receiving section connected to said output circuitry for translating a signal voltage thereof into an indication of a transmission characteristic of a transmission path terminating at said receiving station; switch means in at least one of said measuring stations selectively settable in a basic position and at least one alternate position; and conductor means in said one of said measuring stations connected to said output circuitry of the receiving section thereof for energization by at least some of said signal voltages, said conductor means being connected in said alternate position of said switch means to said wave synthesizer of the associated transmitting section for modifying the operation thereof to replicate a parameter of a component of said incoming carrier wave in a corresponding constituent of said outgoing carrier wave, said wave synthesizer being disconnected from said conductor means in said basic position of said switch means.
Claim 2
Independent Claim
268 words
A system for sending amplitude-modulated carrier waves over transmission paths linking a plurality of measuring stations in a closed loop, said stations serving to determine the characteristics of said transmission paths, comprising: a receiving section and a transmitting section at each measuring station; a wave synthesizer in said transmitting section including oscillation-generating means for producing separate highfrequency carrier oscillations and low-frequency modulating oscillations, said wave synthesizer further including modulating means for combining said oscillations into an outgoing amplitude-modulated carrier wave; processing means in said receiving section for isolating a carrier component and a modulating component of an incoming amplitude-modulated carrier wave, said processing means including output circuitry producing signal voltages derived from at least one of said components; evaluation means in said receiving section connected to said output circuitry for translating a signal voltage thereof into an indication of a transmission characteristic of a transmission path terminating at said receiving station; switch means in at least one of said measuring stations selectively settable in a basic position and at least one alternate position; and conductor means in said one of said measuring stations connected to said output circuitry of the receiving section thereof for energization by at least some of said signal voltages, said conductor means being connected in said alternate position of said switch means to said wave synthesizer of the associated transmitting section for modifying the operation thereof to replicate a parameter of a component of said incoming carrier wave in a corresponding constituent of said outgoing carrier wave, said wave synthesizer being disconnected from said conductor means in said basic position of said switch means.
Claim 3
Dependent Claim
35 words
A system as defined in claim 1 wherein said processing means includes a demodulator for detecting the envelope of said incoming carrier wave, said demodulator being connected to said conductor means through said output circuitry.
Claim 4
Dependent Claim
40 words
A system as defined in claim 1 wherein said processing means includes a limiter for deriving from said incoming carrier wave a constant-amplitude oscillation of said carrier frequency, said limiter being connected to said conductor means through said output circuitry.
Claim 5
Dependent Claim
38 words
A system as defined in claim 3 wherein said limiter includes a variable-gain amplifier provided with a feedback circuit and a differential amplifier in said feedback circuit having an input connected to a source of constant reference voltage.
Claim 6
Dependent Claim
48 words
A system as defined in claim 3 wherein said oscillation-generating means includes a variable oscillator provided with tuning means connected to said conductor means in said alternate position of said switch means for conforming the operating frequency of said variable oscillator to the output frequency of said limiter.
Claim 7
Dependent Claim
23 words
A system as defined in claim 5 wherein said output circuitry includes a frequency discriminator inserted between said limiter and said conductor means.
Claim 8
Dependent Claim
51 words
A system as defined in claim 5 wherein said wave synthesizer includes phase-comparison means connected to said variable oscillator and to said conductor means for synchronizing the operating frequency of said variable oscillator with the carrier frequency of said constant-amplitude oscillation received from said limiter by way of said conductor means.
Claim 9
Dependent Claim
95 words
A system as defined in claim 1 wherein said transmitting section includes switchover means for periodically altering the frequency of said carrier oscillations; said processing means including a demodulator for detecting the envelope of said incoming carrier wave, said envelope varying periodically in phase with the frequency of said incoming carrier wave, a low-frequency slave oscillator, and phase-comparison means connected to said slave oscillator and to said demodulator for synchronizing the operating frequency of said slave oscillator with a mean phase of said envelope; said evaluation means including an output connection from said slave oscillator.
Claim 10
Dependent Claim
41 words
A system as defined in claim 8 wherein said processing means further includes a limiter for deriving from said incoming carrier wave a constant-amplitude oscillation of periodically varying frequency, said limiter being connected through said output circuitry to said conductor means.
Claim 11
Dependent Claim
88 words
A system as defined in claim 9 wherein said output circuitry has a plurality of branch circuits with terminals connected on the one hand to said evaluation means and on the other hand to said conductor means, said processing means further including frequency-reducing means connected to said slave oscillator for deriving therefrom a switching frequency in step with the changeover of said incoming carrier wave and gating means connected to said frequency-reducing means for alternately closing certain of said branch circuits in the rhythm of said switching frequency.
Claim 12
Dependent Claim
71 words
A system as defined in claim 10 wherein said oscillation-generating means comprises two carrier oscillators of different frequencies alternately connectable by switchoVer means to said modulating means, said wave synthesizer including separate control circuits for varying the operating frequencies of said carrier oscillators, said conductor means including two conductors alternately energizable by said gating means for respectively energizing said control circuits with signal voltages derived from the output of said limiter.
Claim 13
Dependent Claim
87 words
A system as defined in claim 11 wherein said output circuitry includes two ancillary oscillators each connected to a respective one of said conductors and first phase-comparison means connected to said limiter and to each ancillary oscillator for synchronizing the operating frequency thereof with a respective carrier frequency in the output of said limiter, each of said control circuits including second phase-comparison means connected to said conduction means and to its respective carrier oscillator for synchronizing the operating frequency thereof with that of the respective ancillary oscillator.
Claim 14
Dependent Claim
50 words
A system as defined in claim 10 wherein said output circuitry includes a low-pass filter in the output of said demodulator and storage means connected to said filter in series with said gating means for delivering to said conductor means a signal proportional to the peak amplitude of said envelope.
Claim 15
Dependent Claim
55 words
A system as defined in claim 13 wherein said oscillation-generating means includes a low-frequency master oscillator, said modulating means being directly connected by said conductor means to said storage means, said slave oscillator and said limiter in said alternate position of said switch means while being disconnected from said carrier oscillators and said master oscillator.
Claim 16
Dependent Claim
38 words
A system as defined in claim 10 wherein said frequency reducing means comprises a frequency divider, further including zero-setting means for said frequency divider responsive to a burst of a distinct identification frequency modulating said incoming carrier wave.
References Cited (Backward Citations)
US3629696A
Cited
US3777081A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |