The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 19, 1991
Filed:
Apr. 27, 1989
James L Adcock, Seattle, US;
David E Shoup, Seattle, WA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A digital mixer is supplied with two digitized input signals in complex form. The product of the complex input signals is converted to analog form and provides the desired output signal without any alias terms. The first input signal is desirably stored in a first memory as a sequence of data points corresponding to a complex exponential sinusoid. The second input signal is a baseband excitation waveform that is also stored in complex form in a memory. Operands from these two sources are provided periodically to the mixer for complex multiplication. The sequence of sinusoid operands provided from the first memory is determined by a phase counter that indexes through the memory by a .DELTA..theta. term. .DELTA..theta. is selected so that the data indexed thereby corresponds to samples of a sine wave of the desired frequency. If .DELTA..theta. indexes a signal phase intermediate two complex data in the memory, an interpolated value is provided.