US3836845A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for testing the linearity of a circuit by using ratio determining means
Assignee: RCA Corp
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Filing: 1973-08-03
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Granted: 1974-09-17
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Expires: 1993-08-03
Abstract
Abstract Apparatus for testing the linearity of a circuit includes means for applying a staircase waveform to the circuit under test. The staircase waveform has known ratios between the values of one step and the remaining steps. The staircase waveform as altered by the circuit under test has unknown ratios between the one altered step and the remaining altered steps. Means are provided for determining the ratios of the one step to the remaining steps of the altered staircase waveform and for comparing these ratios to the known ratios existing in the original waveform. The difference between these ratios, if any, is determined and provides by way of a ratio comparator an indication of the linearity of the circuit under test.
Inventors
- 👤 M Payne
- 👤 J Mazgy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 04:59
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/28; G01R31/2832; G01R31/2836; G01R31/2837
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
200 words
An apparatus for measuring the linearity of a circuit, comprising: waveform generating means for generating a staircase waveform having a plurality of sequentially occurring step transitions, the waveform occurring intermediate each pair of adjacent step transitions having a known value different from the value of the waveform occurring intermediate the other adjacent step transitions, the ratio of a given one of said values to each of the other of said values being known a priori, means for applying said staircase waveform to said circuit, said circuit tending to alter the applied waveform in accordance with the linearity and gain of said circuit to produce as an output signal an altered staircase waveform, said altered staircase waveform exhibiting a plurality of step transitions each corresponding to a different one of said sequentially occurring step transitions, and means for determining the ratio of a certain one of said values of said altered waveform to each of the other of said altered waveform values corresponding to those values forming said known ratios and for comparing the determined ratios to said known ratios to thereby produce a linearity output signal manifesting the difference between said ratios, which difference manifests the linearity of said circuit.
Claim 2
Independent Claim
200 words
An apparatus for measuring the linearity of a circuit, comprising: waveform generating means for generating a staircase waveform having a plurality of sequentially occurring step transitions, the waveform occurring intermediate each pair of adjacent step transitions having a known value different from the value of the waveform occurring intermediate the other adjacent step transitions, the ratio of a given one of said values to each of the other of said values being known a priori, means for applying said staircase waveform to said circuit, said circuit tending to alter the applied waveform in accordance with the linearity and gain of said circuit to produce as an output signal an altered staircase waveform, said altered staircase waveform exhibiting a plurality of step transitions each corresponding to a different one of said sequentially occurring step transitions, and means for determining the ratio of a certain one of said values of said altered waveform to each of the other of said altered waveform values corresponding to those values forming said known ratios and for comparing the determined ratios to said known ratios to thereby produce a linearity output signal manifesting the difference between said ratios, which difference manifests the linearity of said circuit.
Claim 3
Independent Claim
160 words
An apparatus for measuring the linearity of a circuit comprising: means for generating a first signal having first and second values, said first and second values having a given ratio therebetween, input means for applying said first signal to said circuit to thereby produce a second signal having respective third and fourth values corresponding to said first and second values, said third and fourth values tending to be different than said first and second values in accordance with the linearity and gain of said circuit, means responsive to said second signal for generating an output signal manifesting the ratio between said third and fourth values, means for generating a ratio reference signal manifesting said given ratio, and linearity measuring means responsive to said output signal and reference signal applied as respective inputs thereto for comparing the given ratio to said generated ratio and providing a signal indicating the difference between said ratios, which difference manifests the linearity of said circuit.
Claim 4
Independent Claim
160 words
An apparatus for measuring the linearity of a circuit comprising: means for generating a first signal having first and second values, said first and second values having a given ratio therebetween, input means for applying said first signal to said circuit to thereby produce a second signal having respective third and fourth values corresponding to said first and second values, said third and fourth values tending to be different than said first and second values in accordance with the linearity and gain of said circuit, means responsive to said second signal for generating an output signal manifesting the ratio between said third and fourth values, means for generating a ratio reference signal manifesting said given ratio, and linearity measuring means responsive to said output signal and reference signal applied as respective inputs thereto for comparing the given ratio to said generated ratio and providing a signal indicating the difference between said ratios, which difference manifests the linearity of said circuit.
Claim 5
Independent Claim
137 words
An apparatus for measuring the linearity of a circuit, comprising: means for generating a waveform having first and second values exhibiting a given ratio therebetween, means for generating a ratio reference signal manifesting said given ratio, means for applying said waveform to said circuit, said circuit tending to alter the values of said waveform in accordance with the linearity and gain of said circuit, means responsive to said altered waveform applied as an input thereof for determining the ratio between said altered first and second values, sand means responsive to said generated ratio reference signal and to the operation of said ratio determining means for comparing the given ratio to said determined ratio to provide as an output thereof a signal manifesting the difference between said ratios, said difference in ratios indicating the linearity of said circuit.
Claim 6
Independent Claim
137 words
An apparatus for measuring the linearity of a circuit, comprising: means for generating a waveform having first and second values exhibiting a given ratio therebetween, means for generating a ratio reference signal manifesting said given ratio, means for applying said waveform to said circuit, said circuit tending to alter the values of said waveform in accordance with the linearity and gain of said circuit, means responsive to said altered waveform applied as an input thereof for determining the ratio between said altered first and second values, sand means responsive to said generated ratio reference signal and to the operation of said ratio determining means for comparing the given ratio to said determined ratio to provide as an output thereof a signal manifesting the difference between said ratios, said difference in ratios indicating the linearity of said circuit.
Claim 7
Independent Claim
111 words
An apparatus for measuring the linearity of a circuit, comprising: means for generating a waveform having first and second values exhibiting a given ratio therebetween, means for applying said waveform to said cricuit, said circuit tending to alter the values of said waveform in accordance with the linearity of said circuit, said altered values exhibiting an unknown ratio therebetween, and means responsive to said generated waveform and said altered waveform for determining said given and unknown ratios and for comparing said given ratio to said unknown ratio to provide as an output thereof a signal manifesting the difference between said ratios, said difference in ratios indicating the linearity of said circuit.
Claim 8
Independent Claim
111 words
An apparatus for measuring the linearity of a circuit, comprising: means for generating a waveform having first and second values exhibiting a given ratio therebetween, means for applying said waveform to said cricuit, said circuit tending to alter the values of said waveform in accordance with the linearity of said circuit, said altered values exhibiting an unknown ratio therebetween, and means responsive to said generated waveform and said altered waveform for determining said given and unknown ratios and for comparing said given ratio to said unknown ratio to provide as an output thereof a signal manifesting the difference between said ratios, said difference in ratios indicating the linearity of said circuit.
Claim 9
Dependent Claim
27 words
The apparatus of claim 4 wherein said circuit is the picture IF circuit in a television receiver and said generated waveform is a modulated staircase wave form.
Claim 10
Dependent Claim
68 words
The apparatus of claim 4 wherein said last-mentioned means includes sampling means for sampling said generated waveform in the time intervals occurring in time coincidence with said first and second values to provide a plurality of sample signals, and means responsive to said sample signals for dividing the value of one of said samples by the value of the other of said samples to provide said unknown ratio.
Claim 11
Dependent Claim
21 words
The apparatus of claim 4 wherein said last-mentioned means includes means for generating a ratio reference signal manifesting said given ratio.
Claim 12
Dependent Claim
137 words
In combination: a staircase waveform generator, means for applying said staircase waveform to a circuit under test to produce a staircase waveform tending to be altered by said circuit, means for establishing a reference level in said altered waveform, means for sampling selected ones of the steps in said altered waveform, means for dividing the value of one of said selected steps by the value of another of said selected steps to provide a signal manifesting an unknown ratio therebetween, means for generating a ratio reference signal manifesting the known ratio between the generated staircase waveform steps corresponding to said one and other selected steps, and means for comparing said known and unknown ratios to generate a signal indicating the linearity of said circuit in accordance with the difference in value between said known and unknown ratios.
Claim 13
Dependent Claim
137 words
In combination: a staircase waveform generator, means for applying said staircase waveform to a circuit under test to produce a staircase waveform tending to be altered by said circuit, means for establishing a reference level in said altered waveform, means for sampling selected ones of the steps in said altered waveform, means for dividing the value of one of said selected steps by the value of another of said selected steps to provide a signal manifesting an unknown ratio therebetween, means for generating a ratio reference signal manifesting the known ratio between the generated staircase waveform steps corresponding to said one and other selected steps, and means for comparing said known and unknown ratios to generate a signal indicating the linearity of said circuit in accordance with the difference in value between said known and unknown ratios.
Claim 14
Dependent Claim
25 words
The combination of claim 8 wherein said staircase waveform has a plurality of steps each spaced a different value with respect to said reference level.
Claim 15
Dependent Claim
42 words
The apparatus of claim 9 whereIn said one selected step is that step having a maximum value with respect to said reference level, said dividing means dividing the value of said one step by the value of each of the other steps.
Claim 16
Dependent Claim
19 words
The apparatus of claim 8 wherein said sampling means includes means for sequentially sampling each of said selected steps.
Claim 17
Dependent Claim
26 words
The apparatus of claim 8 further including control means for causing said dividing means to synchronously generate said unknown ratio signal with said known ratio signal.
Claim 18
Dependent Claim
129 words
In combination: means for generating a test signal having a known ratio between the value of a first portion thereof and a second portion thereof, means for applying said test signal to a circuit under test, said circuit tending to alter said test signal in an unknown manner, means for comparing the value of a first portion of said altered signal corresponding to said test signal first portion to a second portion of said altered signal corresponding to said test signal second protion to generate a signal manifesting an unknown ratio between said first and second portions of said altered signal, and means for comparing said known and unknown ratios to generate a signal indicating the magnitude of the differnece therebetween, said magnitude manifesting the linearity of said circuit.
Claim 19
Dependent Claim
129 words
In combination: means for generating a test signal having a known ratio between the value of a first portion thereof and a second portion thereof, means for applying said test signal to a circuit under test, said circuit tending to alter said test signal in an unknown manner, means for comparing the value of a first portion of said altered signal corresponding to said test signal first portion to a second portion of said altered signal corresponding to said test signal second protion to generate a signal manifesting an unknown ratio between said first and second portions of said altered signal, and means for comparing said known and unknown ratios to generate a signal indicating the magnitude of the differnece therebetween, said magnitude manifesting the linearity of said circuit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |