Electrical computers: arithmetic processing and calculating – Electrical digital calculating computer – Particular function performed
Patent
1997-01-27
1999-11-02
Ngo, Chuong Dinh
Electrical computers: arithmetic processing and calculating
Electrical digital calculating computer
Particular function performed
G06F 1717
Patent
active
059788232
ABSTRACT:
Methods and apparatus for converting a relatively low frequency signal, e.g., a 1.5 MHz signal, to a high frequency signal, e.g., a 30-100 MHz signal, in the digital domain without the need for a digital mixer operating at the high frequency are described. The high frequency represents, e.g., the ultimate digital to analog conversion frequency. In accordance with the present invention an interpolation technique is used to convert the low rate digital signal to a high rate signal and to shift the carrier to a desired frequency. This is accomplished, by first positioning the information signal, e.g., the digital waveform to be modulated on a carrier at a relatively low rate using a digital mixer operating at a fraction of the ultimate digital to analog conversion frequency. The relatively low rate signal generated by the mixing operation is then converted to a high rate signal by one or more interpolator stages. An adjustable passband filter circuit is included in each interpolation stage. In one embodiment, the adjustable passband filter circuits are implemented using a fixed frequency filter preceded and followed by frequency shifting circuits which are used to upshift and then downshift the signal being filtered. By controlling the frequency shifting adjustable filter circuits are achieved via the use of fixed filters. One feature of the present invention is directed to a control circuit which is response to an H bit frequency control word representing a desired output carrier frequency.
REFERENCES:
patent: 4516078 (1985-05-01), Yanagihara et al.
patent: 5300838 (1994-04-01), Elizondo
patent: 5412352 (1995-05-01), Graham
patent: 5534828 (1996-07-01), Okada et al.
patent: 5783974 (1998-07-01), Koslov et al.
Koslov Joshua L.
Lane Frank A.
Scarpa Carl G.
Hitachi America Ltd.
Michaelson Peter L.
Ngo Chuong Dinh
Straub Michael P.
LandOfFree
Methods and apparatus for implementing and controlling a digital does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Methods and apparatus for implementing and controlling a digital, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Methods and apparatus for implementing and controlling a digital will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2150038