Signal monitoring apparatus
First Claim
1. A digital video signal monitoring apparatus comprising:
- means for receiving a digital video signal comprising a plurality of digital signals which have been multiplexed together, each signal comprising a plurality of successive digital sample values;
means for extracting from said digital video signal one of said plurality of digital signals;
an oversampling digital filter for interpolating additional digital values intermediate the successive samples of the extracted digital signal; and
means for displaying the waveform of the extracted digital signal as a plurality of waveforms superimposed over one-another, to give the appearance that the waveform has been oversampled, each of said plurality of waveform comprising a series of discrete points corresponding to the digital sample values and interpolated digital values for a line of a video field, the coefficients of the oversampling digital filter being different for each waveform, wherein each of said plurality of waveforms comprises a series of discrete points corresponding to the digital sample values and interpolated digital values for the same line of a video field and said intermediate digital values are interpolated by recirculating said same line through a buffer whilst varying the coefficients of said oversampling digital filter.
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Abstract
A digital video signal monitoring apparatus comprises means (2,4,6) for receiving a digital video signal and extracting therefrom a plurality of digital signals, each of which comprises a plurality of successive digital sample values. The apparatus further comprises means (10) for interpolating additional digital values intermediate the successive samples of the or each extracted digital signal and means for displaying the waveform of the or each extracted digital signal as a series of discrete points corresponding to its respective digital sample values and interpolated digital values. Thus, none of the original signal information is lost in displaying a signal waveform having a substantially continuous appearance.
52 Citations
51 Claims
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1. A digital video signal monitoring apparatus comprising:
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means for receiving a digital video signal comprising a plurality of digital signals which have been multiplexed together, each signal comprising a plurality of successive digital sample values;
means for extracting from said digital video signal one of said plurality of digital signals;
an oversampling digital filter for interpolating additional digital values intermediate the successive samples of the extracted digital signal; and
means for displaying the waveform of the extracted digital signal as a plurality of waveforms superimposed over one-another, to give the appearance that the waveform has been oversampled, each of said plurality of waveform comprising a series of discrete points corresponding to the digital sample values and interpolated digital values for a line of a video field, the coefficients of the oversampling digital filter being different for each waveform, wherein each of said plurality of waveforms comprises a series of discrete points corresponding to the digital sample values and interpolated digital values for the same line of a video field and said intermediate digital values are interpolated by recirculating said same line through a buffer whilst varying the coefficients of said oversampling digital filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A digital video signal monitoring apparatus comprising:
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means for receiving a digital video signal comprising a plurality of digital signals which have been multiplexed together, each signal comprising a plurality of successive digital sample values;
means for extracting from said digital video signal one of said plurality of digital signals;
an oversampling digital filter for interpolating additional digital values intermediate the successive samples of the extracted digital signal; and
means for displaying the waveform of the extracted digital signal as a plurality of waveform superimposed over one-another, to give the appearance that the waveform has been oversampled, each of said plurality of waveform comprising a series of discrete points corresponding to the digital sample values and interpolated digital values for a line of a video field, the coefficients of the oversampling digital filter being different for each waveform, wherein said oversampling digital filter comprises a transversal FIR filter whose coefficients are derived from a sin(x)/x low-pass impulse response curve. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A digital video signal monitoring apparatus comprising:
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means for receiving a digital video signal comprising a plurality of digital signals which have been multiplexed together, each signal comprising a plurality of successive digital sample values;
means for extracting from said digital video signal one of said plurality of digital signals;
an oversampling digital filter for interpolating additional digital values intermediate the successive samples of the extracted digital signal;
means for displaying the waveform of the extracted digital signal as a plurality of waveforms superimposed over one another, to give the appearance that the waveform has been oversampled, each of said plurality of waveform comprising a series of discrete points corresponding to the digital sample values and interpolated digital values for a line of a video field, the coefficients of the oversampling digital filter being different for each waveform; and
means for digitally generating horizontal and vertical cursors to allow amplitude and/or timing measurements to be made of a displayed signal waveform. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51)
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Specification