US4204228A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital testing apparatus
Assignee: Independent Broadcasting Authority
•
Filing: 1978-05-09
•
Granted: 1980-05-20
•
Expires: 1998-05-09
Abstract
Abstract Apparatus is disclosed for producing a test signal having a predetermined amount of distortion, including a first pulse generator (11) for producing a plurality of first pulses, a distortion pulse generator (18, 21) for producing a plurality of distortion pulses, and an adder circuit for adding the first and distortion pulses to produce a composite signal having a main portion of amplitude and shape identical to the first pulse and to which is added at least one of the distortion pulses.
Inventors
- 👤 Arthur G. Mason
- 👤 Peter R. Hutt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 06:35
CPC Classifications
H; H04; H04L; H04L1/00; H04L1/24; H04N; H04N7/00; H04N7/025; H04N7/035
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
90 words
Apparatus for producing a test signal having a predetermined amount of distortion, comprising (a) means (10, 11) for generating a plurality of first pulses; (b) delay means (17) for deriving from said first pulses a plurality of distortion pulses having an amplitude proportional to the amplitude of the first pulses; (c) attenuation means (22) for controlling the amplitude of the distortion pulses; and (d) adder circuit means (23) for adding the distortion pulses to the first pulses, whereby the distortion pulses are added in spaced relation to the first pulses.
Claim 2
Dependent Claim
90 words
Apparatus for producing a test signal having a predetermined amount of distortion, comprising (a) means (10, 11) for generating a plurality of first pulses; (b) delay means (17) for deriving from said first pulses a plurality of distortion pulses having an amplitude proportional to the amplitude of the first pulses; (c) attenuation means (22) for controlling the amplitude of the distortion pulses; and (d) adder circuit means (23) for adding the distortion pulses to the first pulses, whereby the distortion pulses are added in spaced relation to the first pulses.
Claim 3
Dependent Claim
67 words
Apparatus as defined in claim 1, wherein said delay means produces distortion pulses of opposite polarity, and further including operational amplifier means (21) connected between said delay means and said adder means, respectively, said operational amplifier means having a pair of inputs to which the distortion pulses of opposite polarity are applied, respectively, said operational amplifier means having an output terminal connected with said adder circuit means.
Claim 4
Dependent Claim
21 words
Apparatus as defined in claim 2, wherein said delay means produces distortion pulses of opposite polarity that have the same shape.
Claim 5
Dependent Claim
20 words
Apparatus as defined in claim 1, wherein said delay means produces distortion pulses of similar shape to said first pulses.
Claim 6
Dependent Claim
44 words
Apparatus as defined in claim 2, wherein the sum of all the positive distortion pulses equals the sum of all the negative distortion pulses, so that the bar height of the resulting composite pulse is not affected by the inclusion of the distortion pulses.
Claim 7
Dependent Claim
27 words
Apparatus as defined in claim 1, wherein the amplitude of the first pulse is equal to the amplitude of the bar height of the resulting composite pulse.
Claim 8
Dependent Claim
38 words
Apparatus as defined in claim 1, wherein the first pulses have a plurality of different levels, and further wherein said attenuation means produces distortion pulses the magnitude of which is proportional to the amplitude of the first pulses.
Claim 9
Dependent Claim
21 words
Apparatus as defined in claim 7, wherein the number of first pulse levels has a positive whole number other than unity.
Claim 10
Dependent Claim
16 words
Apparatus as defined in claim 7, wherein the first pulses have one of two allowable levels.
Claim 11
Dependent Claim
29 words
Apparatus as defined in claim 1, wherein said adder circuit means is operable to produce a composite signal with at least one distortion pulse prior to the first pulse.
Claim 12
Dependent Claim
26 words
Apparatus as defined in claim 1, wherein the composite signal producing means produces the composite signal with at least one distortion pulse after the first pulse.
Claim 13
Dependent Claim
33 words
Apparatus as defined in claim 1, wherein the composite signal producing means produces the composite signal with at least one distortion pulse before, and at least one distortion pulse after, the first pulse.
Claim 14
Dependent Claim
39 words
Apparatus as defined in claim 1, wherein the composite signal producing means combines a plurality of distortion pulses with the first pulse of the composite signal, whereby the distortion pulses do not overlap each other or the first pulse.
Claim 15
Dependent Claim
22 words
Apparatus as defined in claim 13, wherein the distortion pulse is added at a multiple of the interval between the first pulses.
Claim 16
Dependent Claim
27 words
Apparatus as defined in claim 1, wherein the composite signal producing means comprises means for combining the distortion pulse with the first pulse of the composite signal.
Claim 17
Dependent Claim
27 words
Apparatus as defined in claim 15, wherein the delay means is connected with a data pulse receiving means for deriving the distortion pulses from said first pulses.
Claim 18
Dependent Claim
14 words
Apparatus as defined in claim 1, wherein said delay means comprise analog delay means.
Claim 19
Dependent Claim
14 words
Apparatus as defined in claim 1, wherein said delay means comprise digital delay means.
Claim 20
Dependent Claim
46 words
Apparatus as defined in claim 1, wherein said attenuation means is operable to alter the ratio between the amplitudes of the distortion pulses and the first pulses to produce a linear relationship between the alteration of this ratio and the distortion introduced into the composite signal.
Claim 21
Dependent Claim
17 words
Apparatus as defined in claim 1, wherein said attenuation means is adjustable in a continuously variable manner.
Claim 22
Dependent Claim
17 words
Apparatus as defined in claim 1, wherein said attenuation means is adjustable in a step-wise variable manner.
Claim 23
Dependent Claim
38 words
Apparatus as defined in claim 1, wherein at least one distortion pulse is combined with the first pulses to produce a reduction in bar height, and further including compensation means for compensating for the reduction in bar height.
Claim 24
Dependent Claim
21 words
Apparatus as defined in claim 1, and further including indicating means for indicating the amount of distortion in the composite signal.
Claim 25
Dependent Claim
30 words
Apparatus as defined in claim 1, and further including means for generating scanning signals and blanking signals for facilitating an oscilloscope display of an eye diagram of the composite signal.
Claim 26
Dependent Claim
51 words
Apparatus as defined in claim 1, wherein said first pulses are teletext signals, and further including means (15) for generating a video test signal, and means (14) for producing the necessary line and field synchronization pulses to which teletext signals have been added in appropriate lines of the field blanking time.
Claim 27
Dependent Claim
37 words
Apparatus as defined in claim 25, wherein the video test signal is a teletext pulse and teletext bar signal comprising a bar of several microseconds duration followed by a single teletext pulse well separated from that bar.
Claim 28
Dependent Claim
21 words
Apparatus according to claim 25, and further including means for generating a video test signal with a predeterminable amount of distortion.
Claim 29
Dependent Claim
29 words
Apparatus as defined in claim 25, wherein the distortion applied to the video test signal has a form which is identical to the distortion applied to the first pulses.
Claim 30
Dependent Claim
32 words
Apparatus as defined in claim 25, and further including indicating means for displaying the variable amount of distortion which has been applied simultaneously to the first pulses and the video test signal.
Claim 31
Dependent Claim
40 words
Apparatus as defined in claim 25, and further including means (25) for controllably removing distortion applied simultaneously to the first pulses and the video test signal from the video test signal while leaving the distortion present on the first pulses.
Claim 32
Dependent Claim
29 words
Apparatus as defined in claim 1, and further including means (26) for controlling the production of distortion pulses so that the distortion cannot affect certain groups of first pulses.
Claim 33
Dependent Claim
45 words
Apparatus as defined in claim 30, wherein the data signal constitutes a teletext signal, and the means (26) for controlling the production of distortion pulses to remove distortion from initial portions of the teletext signals includes a 16-bit run-in group followed by an 8-bit framing-code.
Claim 34
Dependent Claim
43 words
Apparatus as defined in claim 1, and further including means operable in synchronism with a data pulse generator for providing externally accessible signals which have the same timing and similar shape to the first pulse timing waveform and the first pulse sequence waveform.
Claim 35
Dependent Claim
18 words
Apparatus according to claim 33, wherein external signals are provided at the voltage level of standard logic-level signals.
Claim 36
Dependent Claim
47 words
Apparatus as defined in claim 1, and further including modulator means (M) permitting data signals with a predetermined amount of distortion to be employed as an input, thereby providing a radio-frequency signal for the testing of data receiving equipments which require such a signal as an input.
Claim 37
Dependent Claim
46 words
Apparatus as defined in claim 1, and further including modulator means so operable that data signals interleaved with standard video signals are used to provide a source of standard modulated television radio-frequency waveform which may be used for the testing of television and data receiving equipment.
Claim 38
Dependent Claim
15 words
Apparatus according to claim 36, wherein the data signal consists of a standard teletext signal.
Claim 39
Dependent Claim
39 words
Apparatus as defined in claim 1, wherein said first pulse generating means further includes digital store means where information is stored and is read out in a cyclic manner, thereby determining the pattern of a repeating sequence of pulses.
Claim 40
Dependent Claim
19 words
Apparatus as defined in claim 38, and further including means for erasing and replacing information in said digital store.
Claim 41
Dependent Claim
29 words
Apparatus as defined in claim 38, wherein the data signal which generated from the stored digital signal is a teletext signal which is interleaved with a standard video signal.
Claim 42
Dependent Claim
26 words
Apparatus as defined in claim 38, wherein a radio-frequency signal is generated consisting of a modulated cyclically repeating data signal interleaved with a video test signal.
References Cited (Backward Citations)
US4109100A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-05-20 | 1983-11-19 | 1984-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-05-20 | 1987-11-19 | 1988-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-05-20 | 1991-11-19 | 1992-05-20 | $7700.00 | Window Closed / Lapsed |