Telecommunications – Receiver or analog modulated signal frequency converter – Frequency modifying or conversion
Reexamination Certificate
2008-01-15
2008-01-15
Urban, Edward F. (Department: 2618)
Telecommunications
Receiver or analog modulated signal frequency converter
Frequency modifying or conversion
C455S158300, C455S339000, C375S319000
Reexamination Certificate
active
07319852
ABSTRACT:
An apparatus for coarse compensation of a direct current (DC) offset in a direct to baseband receiver architecture utilizes a serial analog to digital converter (ADC), such as a Delta-Sigma converter, to convert the received signal to digital form. The output of the ADC is sampled for a predetermined number of samples and a counter coupled to the ADC is incremented each time the sample generated by the ADC is a logic one. The counter is not incremented if the sample from the ADC is a logic zero. After the predetermined number of samples is obtained, the counter value is indicative of the DC offset in the received signal. The counter value may be converted by a code converter to a correction value for easy operation of a digital to analog converter (DAC). If the number of samples from the ADC is a power of two, the code converted may be readily implemented by simply inverting the most significant bit (MSB) from the counter to thereby generate a twos complement version of the counter value. The correction value is coupled to the DAC to generate a compensation signal, which is provided to the received signal path in the form of a feedback signal to compensate for the DC offset.
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Filipovic Daniel
Holenstein Christian
Kasturi Nitin
Schlegel Nikolai
Le Nhan T.
Mobarhan Ramin
Qualcomm Incorporated
Rouse Thomas R.
Seo Howard H.
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