Down/up-conversion apparatus and method
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsThorsten Schier, Svante Signell
Life of this patent
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Abstract
A down-converter converts an amplitude modulated high frequency signal into a low frequency or baseband signal. A first mixer (30, 32) mixes the high frequency signal into a composite signal having an in-phase component and a quadrature component. A complex bandpass filter (34) bandwidth limits the composite signal into a bandwidth limited signal with an in-phase component and a quadrature component. A second mixer (36, 38) mixes the bandwidth limited signal into an intermediate signal with an in-phase component and a quadrature component, and an adder (40) adds one component of the intermediate signal to the other. A similar up-converter performs the reverse process.
Claims10
A down-converter for converting a modulated high frequency signal into a low frequency signal, including a first mixer for mixing said high frequency signal into a composite signal having an in-phase component and a quadrature component, said down-converter comprising:
- A/D converters for A/D conversion of the components of said composite signal:
- a complex bandpass filter, coupled to the output of said first mixer, for bandwidth limiting said composite signal into a bandwidth limited signal having an in-phase component and a quadrature component, wherein said complex bandpass filter is a digital bandpass filter, and wherein said complex bandpass filter is a complex bilinear ladder filter;
- a second mixer, coupled to the output of said complex bandpass filter, for mixing said bandwidth limited signal into an intermediate signal having an in-phase component and a quadrature component, wherein said second mixer is a digital mixer;
- and
- an adder, coupled to the output of said second mixer, for adding (subtracting) one component of said intermediate signal to (from) the other component, wherein said adder is a digital adder.
An up-converter for converting a low frequency digital signal into a modulated high frequency signal, including a first digital mixer for mixing said low frequency signal into a composite signal having an in-phase component and a quadrature component, said up-converter comprising:
- a complex digital bandpass filter, coupled to the output of said first digital mixer, for bandwidth limiting said composite signal into a bandwidth limited signal having an in-phase component and a quadrature component, wherein said complex bandpass filter is a complex bilinear digital ladder filter;
- D/A converters for D/A conversion of the components of said bandwidth limited signal;
- a second mixer, coupled to the output of said D/A converters, for mixing said bandwidth limited signal into an intermediate signal having an in-phase component and a quadrature component;
- and
- an adder, coupled to the output of said second mixer, for adding (subtracting) one component of said intermediate signal to (from) the other component.
An up-converter for converting a low frequency digital signal into a modulated high frequency signal, including a first digital mixer for mixing said low frequency signal into a composite signal having an in-phase component and a quadrature component, said up-converter comprising:
- a set of D/A converters for D/A conversion of the components of said composite signal;
- a complex bandpass filter, coupled to the output of said D/A converters, for bandwidth limiting said composite signal into a bandwidth limited signal having an in-phase component and a quadrature component, wherein said complex bandpass filter is a complex switched capacitor filter;
- a set of A/D converters for A/D conversion of the components of said bandwidth limited signal;
- a second mixer, coupled to the output of said A/D converters, for mixing said bandwidth limited signal into an intermediate signal having an in-phase component and a quadrature component;
- and
- an adder, coupled to the output of said second mixer, for adding (subtracting) one component of said intermediate signal to (from) the other component.
An up-converter for converting a low frequency digital signal into a modulated high frequency signal, including a first digital mixer for mixing said low frequency signal into a composite signal having an in-phase component and a quadrature component, said up-converter comprising;
- a first set of D/A converters for D/A conversion of the components of said composite signal;
- a complex bandpass filter, coupled to the output of said D/A converters, for bandwidth limiting said composite signal into a bandwidth limited signal having an in-phase component and a quadrature component, wherein said complex bandpass filter is a complex switched capacitor filter;
- a second digital mixer, coupled to the output of said complex bandpass filter, for mixing said bandwidth limited signal into an intermediate signal having an in-phase component and a quadrature component;
- a digital adder;
- coupled to the output of said second digital mixer, for adding (subtracting) one component of said intermediate signal to (from) the other component;
- and
- a further D/A converter for D/A conversion of the output signal from said digital adder.
An apparatus for reconstructing a low frequency signal from a composite signal having an in-phase component and a quadrature component, comprising:
- A/D converters for A/D conversion of the components of said composite signal;
- a complex bandpass filter for bandwidth limiting said composite signal into a bandwidth limited signal having an in-phase component and a quadrature component, wherein said complex bandpass filter is a complex bilinear digital ladder filter;
- a digital mixer, coupled to the output of said complex bandpass filter, for mixing said bandwidth limited signal into an intermediate signal having an in-phase component and a quadrature component;
- and
- a digital adder, coupled to the output of said mixer, for adding (subtracting) one component of said intermediate signal to (from) the other component.
An apparatus for generating a high frequency signal from a digital composite signal having an in-phase component and a quadrature component comprising:
- a complex bandpass filter for bandwidth limiting said component signal into a bandwidth limited signal having an in-phase component and a quadrature component, wherein said complex bandpass filter is a complex bilinear digital ladder filter;
- D/A converters for D/A conversion of the components of said bandwidth limited signal;
- a mixer, coupled to the output of said D/A converters, for mixing said bandwidth limited signal into an intermediate signal having an in-phase component and a quadrature component;
- and
- an adder, coupled to the output of said mixer, for adding (subtracting) one component of said intermediate signal to (from) the other component.
An apparatus for generating a high frequency signal from a composite digital signal having an in-phase component and a quadrature component comprising:
- a set of D/A converters for D/A conversion of the components of said composite digital signal,
- a complex bandpass filter for bandwidth limiting said component signal into a bandwidth limited signal having an in-phase component and a quadrature component, wherein said complex bandpass filter is a complex switched capacitor filter;
- a set of A/D converters for A/D conversion of the components of said bandwidth limited signal;
- a mixer, coupled to the output of said A/D converters, for mixing said bandwidth limited signal into an intermediate signal having an in-phase component and a quadrature component;
- and
- an adder, coupled to the output of said mixer, for adding (subtracting) one component of said intermediate signal to (from) the other component.
Dependencies are inferred from the claim text.