Telecommunications – Receiver or analog modulated signal frequency converter – Frequency modifying or conversion
Reexamination Certificate
2007-01-16
2007-01-16
Vuong, Quochien B. (Department: 2618)
Telecommunications
Receiver or analog modulated signal frequency converter
Frequency modifying or conversion
C296S067000, C296S067000, C375S320000, C375S349000
Reexamination Certificate
active
10746200
ABSTRACT:
A DCR RF front-end removes the DC term resulting from mixer port to port leakage and feeds RF and LO signals into the mixers with different phase combinations. The signal inputs to the mixers result in the intermediate frequency (IF) output of mixers being 180 degrees out of phase and their DC terms in phase. When subtracting the two outputs from each other the IF signals add up while the DC terms cancel giving a DC free output. A DC offset feedback tuning loop detects the DC offset in the IF domain and then feeds back the tuning voltage to current injection mixers. A multiplier cancels the IF signals and amplifies the DC offset and a comparator compares the amplified DC offset with a threshold voltage and controls the gain of current injection mixers. The feedback tuning loop thus tracks time-varying DC offsets in real-time.
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Tear Chin Boon
Wong Sheng Jau
Zheng Yuanjin
Ackerman Stephen B.
Agency for Science Technology and Research
Saile Ackerman LLC
Vuong Quochien B.
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