Reduction of aliasing distortion in sampled signals
AssigneeBell Telephone Laboratories, Incorporated
InventorRobert Lawrence Carbrey
Life of this patent
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Abstract
A method and apparatus for sampling continuous wave signals to reduce aliasing distortion. The signal is sampled at n times the Nyquist rate, where n is an integer greater than 1; and the n most recently produced sequential samples are combined at the Nyquist rate to produce a sequence of composite samples. This sequence of composite samples exhibits reduced aliasing distortion compared with a conventional sampling or sample-and-hold gate.
Claims16
The method of generating, at rate f, pulse amplitude modulation (PAM) samples corresponding to a continuous wave signal and reducing aliasing distortion, said signal having a highest frequency of interest not exceeding f/2, comprising the steps of:
- sampling said signal nf times per second where n is an integer greater than 1, and
- combining the n most recently taken samples f times per second to produce by each of such sample combinations one of the PAM samples.
In an apparatus for generating, at rate f, pulse amplitude modulation (PAM) samples corresponding to a continuous wave signal having a highest frequency of interest not exceeding f/2 said apparatus including a plurality of storage capacitors, the method of reducing aliasing distortion comprising the steps of:
- sampling said signal nf times per second where n is an integer greater than 1, and
- combining the n most recently taken samples f times per second to produce by each of such sample combinations one of the PAM samples.
In an apparatus for producing samples of a continuous wave signal, said apparatus including first and second terminals for receiving said signal, the improvement comprising:
- a source of a plurality of control signals,
- a third terminal,
- a first switch normally connecting said first and third terminals and responsive to a first one of said control signals to disconnect said terminals,
- at least one storage network connected between said second and third terminals, each storage network comprising a capacitor and a normally open switch, in series with said capacitor, operative to close in response to a second one of said control signals, and
- a storage capacitor connected between said second and third terminals.
In an apparatus for producing f samples per second of a continuous wave input signal having a highest frequency of interest not exceeding f/2, the improvement comprising:
- means for taking nf samples per second of said signal, where n is an integer greater than 1, and
- means for adding n sequential ones of said samples.
Dependencies are inferred from the claim text.