Digital bandpass oscilloscope
First Claim
1. A digital oscilloscope for displaying a representation of frequency components of an analog signal during a time window, the time window having an adjustable duration, the oscilloscope comprising:
- digitizing means responsive to said analog signal for generating a first data sequence representative of said analog signal during said time window;
filter means responsive to said first data sequence for bandpass filtering and first data sequence to produce a second data sequence; and
display means for displaying said representation according to said second data sequence.
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Accused Products
Abstract
A digital bandpass oscilloscope permits an operator to observe both time and frequency domain plots of analog signal components of frequency within a passband of selected center frequency during a time window of selected duration. The input signal is digitized, and the resulting digital data sequence is bandpass filtered and decimated by an adjustable decimation ratio to produce stored waveform data indicating the time dependent behavior of the passband during the time window. The oscilloscope, which utilizes the waveform data to produce both time and frequency domain displays of the passband, adjusts the decimation ratio to ensure that the number of data elements in the waveform data sequence is constant regardless of the selected duration of the time window and adjusts the bandwidth of the passband to minimize aliasing in the time domain display.
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Citations
35 Claims
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1. A digital oscilloscope for displaying a representation of frequency components of an analog signal during a time window, the time window having an adjustable duration, the oscilloscope comprising:
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digitizing means responsive to said analog signal for generating a first data sequence representative of said analog signal during said time window; filter means responsive to said first data sequence for bandpass filtering and first data sequence to produce a second data sequence; and display means for displaying said representation according to said second data sequence. - View Dependent Claims (2, 3, 4)
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5. A digital oscilloscope for displaying a representation of frequency components of an analog signal during a time window, the time window having an adjustable duration, the oscilloscope comprising:
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digitizing means responsive to said analog signal for generating a first data sequence representative of said analog signal during said time window; filter means responsive to said first data sequence for bandpass filtering and first data sequence according to an adjustable center frequency and an adjustable bandwidth to produce a second data sequence; and means for displaying said representation according to said second data sequence. - View Dependent Claims (6)
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7. A digital oscilloscope for displaying a representation of frequency components of an analog signal, the oscilloscope comprising:
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digitizing means responsive to said analog signal for generating a first data sequence representative of said analog signal during a time window of adjustable duration; and data processing means for quadrature modulating, lowpass filtering and decimating said first data sequence to produce waveform data, and for interpolating and quadrature demodulating said waveform data to produce a second data sequence representative of components of said analog signal included within a passband of adjustable center frequency and adjustable bandwidth. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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16. A digital oscilloscope for displaying a representation of frequency components of an analog signal, the oscilloscope comprising:
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digitizing means responsive to said analog signal for generating a first data sequence representative of said analog signal during a time window of adjustable duration; data processing means for quadrature modulating, lowpass filtering and decimating said first data sequence to produce waveform data, and for interpolating and quadrature demodulating said waveform data to produce a second data sequence representative of components of said analog signal included within a frequency band of adjustable center frequency and adjustable bandwidth; means for storing said waveform display data; and means for displaying a time domain representation of said analog signal components according to said second data sequence. - View Dependent Claims (17, 18)
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19. A method for displaying a representation of frequency component os an analog signal during a time window, the time window having an adjustable duration, the method comprising the steps of:
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digitizing said analog signal to produce a first data sequence representative of said analog signal during said time window; bandpass filtering said first data sequence according to an adjustable bandwidth to produce a second data sequence; and displaying said representation according to said second data sequence. - View Dependent Claims (20, 21, 22)
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23. A method for displaying a representation of time dependent behavior of frequency components of an analog signal during a time window, the time window having an adjustable duration, the method comprising the steps of:
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generating a first data sequence representative of said analog signal during said time window; bandpass filtering said first data sequence according to an adjustable center frequency and an adjustable bandwidth to produce a second data sequence; and displaying said representation according to said second data sequence. - View Dependent Claims (24)
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25. A method for displaying a representation of frequency components of an analog signal, the method comprising the steps of:
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generating a first data sequence representative of said analog signal during a time window of adjustable duration; quadrature modulating said first data sequence to produce second and third data sequences; lowpass filtering and decimating said second and third data sequences to produce fourth and fifth data sequences; interpolating said fourth and fifth data sequences to produce sixth and seventh data sequences; and quadrature demodulating said sixth and seventh data sequences to produce an eighth data sequence representative of components of said analog signal included within a frequency band of adjustable center frequency and adjustable bandwidth. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
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33. A method for displaying a representation of frequency components of an analog signal, the method comprising the steps of:
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generating a first data sequence representative of said analog signal during a time window of adjustable duration; quadrature modulating said first data sequence to produce second and third data sequences; lowpass filtering and decimating said second and third data sequences to produce fourth and fifth data sequences; storing said fourth and fifth data sequences in memory means; interpolating said fourth and fifth data sequences to produce sixth and seventh data sequences; quadrature demodulating said sixth and seventh data sequences to produce an eighth data sequence representative of components of said analog signal included within a frequency band of adjustable center frequency and adjustable bandwidth; and displaying a time domain representation of said analog signal components according to said eighth data sequence. - View Dependent Claims (34, 35)
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Specification