Signal synchronization
AssigneePixel Instruments Corp.
InventorsJ. Carl Cooper, Steve Anderson
Life of this patent
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Abstract
An apparatus and method is disclosed for converting an input signal having frequency related information sustained over a first duration of time into an output signal sustained over a second duration of time at substantially the same first frequency by adding or subtracting to the effective wave length of the output signal. Preferably, the signals are converted in digital form with samples added or subtracted to frequency convert the signal.
Claims34
A method of synchronizing a signal having frequency related information timed relative to a first time reference to a second signal on an associated channel timed relative to the same time reference which first signal may or may not be synchronized to the second signal at any point in actual time, the second signal being subject to a delay which may vary in respect to the first signal, the first signal having an alpha length;
- said method comprising determining the time differential between the first signal and the second signal on the associated channel and then altering the alpha length of the first signal in response to time differential to compensate for the delay which may vary of the second signal.
An apparatus for synchronizing a signal having frequency related information timed relative to a first time reference to a second signal on an associated channel timed relative to the same time reference which first signal may or may not be synchronized to the second signal at any point in actual time,
- the second signal being subject to a delay which may vary in respect to the first signal, the first signal having an alpha length,
- said apparatus comprising means for determining the time differential between the first signal and the second signal on the associated channel and means for altering the alpha length of the first signal in response to time differential to compensate for the delay which may vary of the second signal.
An apparatus for imparting a changing delay to an audio signal which is associated with an image which is subject to differing processing time periods including in combination:
- a) a delay for delaying digital samples of said audio signal for a time period which may vary;
- b) a control circuit coupled to said delay for varying said time period;
- c) a pitch correction circuit responsive to said digital samples in delayed or undelayed form for correcting pitch artifacts which may occur during said varying of said time period.
A method for imparting a changing delay to an audio signal which is associated with an image which is subject to differing processing time periods including in combination:
- a) delaying digital samples of said audio signal for a time period which may vary;
- b) varying said time period by a control circuit coupled to said delay;
- c) correcting pitch artifacts which may occur during said varying of said time period by a pitch correction circuit responsive to said digital samples in delayed or undelayed form.
An apparatus for synchronizing an audio signal having frequency related information timed relative to a first time reference to a video signal on an associated channel timed relative to the same time reference which audio signal may or may not be synchronized to the video signal at any point in actual time,
- the video signal being subject to a delay which may vary in respect to the audio signal due to the processing of the video signal, the audio signal having an alpha length,
- said apparatus comprising means for determining the time differential between the audio signal and the video signal on the associated channel, means for altering the alpha length of the audio signal in response to time differential to compensate for the delay which may vary of the video signal to synchronize the audio to the video signal,
- the alteration of the alpha length of the audio signal causing pitch artifacts,
- and pitch correction means for correcting said pitch artifacts occasioned during the alteration of the alpha length of the audio signal.
Dependencies are inferred from the claim text.