Coded data generation or conversion – Analog to or from digital conversion – Differential encoder and/or decoder
Reexamination Certificate
2007-06-26
2007-06-26
Nguyen, Khai M. (Department: 2819)
Coded data generation or conversion
Analog to or from digital conversion
Differential encoder and/or decoder
C341S152000, C375S219000, C375S242000, C375S247000, C375S295000, C375S298000, C455S091000
Reexamination Certificate
active
11337189
ABSTRACT:
A self-tuning filter that is well suited for use as a output digital filter in a direct conversion delta-sigma transmitter is constructed as a high pass finite impulse response filter having a cutoff frequency of twice the desired carrier frequency. The filter is clocked using the same clock as used for the commutatation within the transmitter. The aliasing effect of the digital filter produces a passband centered around the carrier frequency which allows the information contained in the spectrum around the passband to be transmitted, while effectively filtering out the quantization noise produced by the commutation. When the commutator clock frequency is changed in order to change the carrier frequency, the passband automatically moves to track the new carrier frequency. The output filter may be constructed using series connected flip-flops with analog taps and an analog summer connected to respective Q andQoutputs, thereby producing an analog output.
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Intellectual Property Law Office of Joel D. Voelzke
Nguyen Khai M.
TechnoConcepts, Inc.
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