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US 7,627,303 B2Granted
Signal downconverter
AssigneeWipro Limited
InventorsThomas Stoll, Peter Widerin
Life of this patent
Estimating the term…
Abstract
A signal downconverter having a pair of passive double sideband mixers for receiving quadrature RF signals and mixing the same with local oscillator driving signals to provide mixed differential signals. The mixed differential signals are fed to a differential difference feedback amplifier high frequency ripples are eliminated and finally providing a down converted output signal.
Claims16
A signal downconverter comprising:
- a first and second mixer for receiving and mixing radio frequency signals to provide a first and second mixed differential signal, each mixed differential signal having a low and a high frequency component;
- and
- an amplifier coupled to the first and second mixer for receiving the mixed differential signals and further processing the mixed differential signals to provide a down converted signals free of the high frequency component, wherein the amplifier is a differential difference amplifier having a pair of differential inputs for receiving the first and second mixed differential signals, and wherein the differential difference amplifier comprises a differential input stage for receiving the first and second mixed differential signals, a high gain amplifier coupled to the differential input stage and a negative differential feedback loop coupling the outputs of the high gain amplifier to the differential input stage.
A signal downconverter comprising:
- a first and second mixer for receiving and mixing radio frequency signals to provide a first and second mixed differential signal, each mixed differential signal having a low and a high frequency component;
- and
- an amplifier coupled to the first and second mixer for receiving the mixed differential signals and further processing the mixed differential signals to provide a down converted signals free of the high frequency component, wherein each of the first and second mixer comprises four field effect transistors (FETs) M1, M2, M3 and M4 connected in a ring configuration, the drain terminals of a first pair of FETs M1, M2 being for receiving a first RE signal and the source terminals of a second pair of FETs M3, M4 being for receiving a second RF signal which is complementary to the first RF signal, the gate terminals of FETs M1, M4 being driven by a first local oscillator signal, the gate terminals of FETs M2, M3 being driven by a second local oscillator signal which is complementary to the first local oscillator signal, the source terminal of FET M1 being coupled to the drain terminal of FET M3 to provide a first mixed signal and the source terminal of FET M2 being coupled to the drain terminal of FET M4 to provide a second mixed signal, the first and second mixed signals forming a mixed differential signal.
An integrated circuit structure having a signal downconverter formed as a part thereof, the signal downconverter comprising:
- a first and second double sideband passive mixer for receiving differential input signals and producing mixed differential signals, each mixed differential signal having low and high frequency components;
- and
- an amplifier coupled to the first and second mixer to collectively form a single sideband mixer, the output of which being a differential output signal free of the high frequency component, wherein the amplifier being a differential difference amplifier comprising a differential input stage for receiving the mixed differential signals and eliminating common mode components thereof and a high gain stage coupled to the differential input stage for amplifying signals therefrom to provide the differential output signal, and wherein the differential difference amplifier further comprising a gain setting circuit acting as negative feedback for affecting the overall gain of the differential difference amplifier, the gain setting circuit comprising a voltage divider coupling the differential output signal to the differential input stage.
Dependencies are inferred from the claim text.