Sampling frequency converter including a sigma-delta modulator
First Claim
1. Sampling frequency converter for converting the sampling frequency of a discrete-time signal from a first frequency to a second frequency, comprising:
- a first clock pulse generator for generating first clock pulses which occur with the first frequency,a second clock pulse generator for generating second clock pulses which occur with the second frequency,selecting means for supplying selected samples of the discrete-time signal at the rhythm of third clock pulses which occur with a third frequency,a selection signal generator for generating the third clock pulses, characterized in that the selection signal generator comprises;
a frequency meter for generating a control signal in response to a frequency difference between the second frequency and a frequency which is proportional to the third frequency,a sigma-delta modulator for converting the control signal into an at least binary decision signal,a validation gate for generating the third clock pulses in response to the first clock pulses by suppressing and passing the first clock pulses during first and second decision signal values respectively.
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Accused Products
Abstract
Sampling frequency converter for converting the sampling frequency of a discrete-time signal (di) from a first sampling frequency (fi) to a second sampling frequency (fo) by sample validation, the number of samples of the discrete-time signal being omitted (or repeated) per unit of time depending on the frequency difference between the first and second sampling frequencies, so that a validated sample sequence is developed with a third sampling frequency having a value fv which, in essence, is equal to the value fo (or fi), the converter including a frequency meter (52) for converting a frequency difference between the second (or first) and third sampling frequencies to a control signal (vc) which is a measurement for the frequency difference, a sigma-delta modulator (10) for converting the control signal to an at least binary decision signal (24), and a validation circuit (48) for omitting (or repeating) a sample from the discrete-time signal di in response to the decision signal.
34 Citations
8 Claims
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1. Sampling frequency converter for converting the sampling frequency of a discrete-time signal from a first frequency to a second frequency, comprising:
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a first clock pulse generator for generating first clock pulses which occur with the first frequency, a second clock pulse generator for generating second clock pulses which occur with the second frequency, selecting means for supplying selected samples of the discrete-time signal at the rhythm of third clock pulses which occur with a third frequency, a selection signal generator for generating the third clock pulses, characterized in that the selection signal generator comprises; a frequency meter for generating a control signal in response to a frequency difference between the second frequency and a frequency which is proportional to the third frequency, a sigma-delta modulator for converting the control signal into an at least binary decision signal, a validation gate for generating the third clock pulses in response to the first clock pulses by suppressing and passing the first clock pulses during first and second decision signal values respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification