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US 5,692,009 AGranted
Jitter measuring method and apparatus
AssigneeLeader Electronics Corporation
InventorMasahiko Iijima
Life of this patent
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Abstract
A jitter measuring method and apparatus is provided which is capable of measuring jitters in serial digital signals transmitted at a high bit rate. The method and apparatus detects from a serial digital signal frequency deviations of a predetermined frequency corresponding to a predetermined period. The detected frequency deviations are converted to period deviations of the predetermined period.
Claims17
A method for measuring a jitter in a digital data signal transmitted at a bit rate, comprising the steps of:
- (a) defining a predetermined period associated with predetermined waveform portions included in said digital data signal, said predetermined waveform portions being used for measuring the jitter in the digital data signal;
- (b) defining a maximum width of fluctuation of period for fluctuations of periods of said predetermined waveform portions from said predetermined period, said fluctuations of the periods of said predetermined waveform portions from said predetermined period being detected as the jitter;
- (c) detecting a signal from said digital data signal, said detected signal including frequency components within a first range of frequency, said first range of frequency including a predetermined frequency corresponding to said predetermined period and having a bandwidth corresponding to said maximum width of fluctuation of period;
- and
- (d) displaying said jitter from said detected signal.
2 more elements
An apparatus for measuring a jitter in a digital data signal transmitted at a bit rate, comprising:
- (a) detecting means coupled to receive said digital data signal for generating a detected signal including frequency components present within a first range of frequency in said digital data signal, said first range of frequency being determined by a predetermined frequency and a bandwidth, said predetermined frequency corresponding to a predetermined period associated with predetermined waveform portions included in said digital data signal, said predetermined waveform portions being used for measuring the jitter in the digital data signal, said bandwidth corresponding to a maximum width of fluctuation of period for fluctuations of periods of said predetermined waveform portions from said predetermined period, said fluctuations of the periods of said predetermined waveform portions from said predetermined period being detected as the jitter;
- and
- (b) display means for displaying the jitter from said detected signal and a first oscillation signal having a first frequency.
Dependencies are inferred from the claim text.