Electrical computers: arithmetic processing and calculating – Electrical digital calculating computer – Particular function performed
Patent
1996-05-24
2000-10-31
Ngo, Chuong Dinh
Electrical computers: arithmetic processing and calculating
Electrical digital calculating computer
Particular function performed
G06F 1717
Patent
active
061416711
ABSTRACT:
An asynchronous digital sample rate converter includes a random access memory for storing input data values and a read only memory for storing a reduced set of interpolation filter coefficients. Input data is written to the random access memory at the input sample rate. Output samples are provided from a multiply/accumulate engine which given a stream of input data and filter coefficients produces an output sample upon request at the output frequency. The initial address for reading input data from the random access memory, and the addresses for coefficients from the read only memory are provided by an auto-centering scheme which is a first order closed loop system with a digital integrator fed by an approximation of the input to output sample rate ratio. This auto-centering scheme may include a feed forward low pass filter to cancel steady state error, and an interpolated write address to reduce noise. A circuit determining the output to input sample rate ratios can also be provided to scale coefficient addresses and resulting output samples to allow for decimation. This circuit includes a form of digital hysteresis to eliminate noise. The ROM coefficients are reduced by relying on the symmetry of the impulse response of the interpolation filter and by utilizing a variable step size forward and backward linear interpolation.
REFERENCES:
patent: 4482975 (1984-11-01), King et al.
patent: 4784578 (1988-11-01), Lagadec et al.
patent: 4802109 (1989-01-01), Machida
patent: 4866647 (1989-09-01), Farrow
patent: 4953117 (1990-08-01), Lagadec
patent: 5023825 (1991-06-01), Luthra et al.
Adams Robert W.
Coln Michael
Kwan Tom W.
Analog Devices Inc.
Ngo Chuong Dinh
LandOfFree
Asynchronous digital sample rate converter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Asynchronous digital sample rate converter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Asynchronous digital sample rate converter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2064860