Granted Patent B2

US 12,652,204 · App. 18/925,572 · Granted Jun 9, 2026

Inventors: Pedro Emiliano Paro Filho (San Diego, CA); Eduardo Rodrigues De Lima (Campinas, BR)

Assignee: Instituto de Pesquisas Eldorado

H04L27/125H04L25/4921H04L27/2082

Abstract

Claims (87)

1 . A digital to analog signal conversion system comprising:

a local oscillator that generates a plurality of local oscillator phase signals;

a control circuit that receives a baseband in-phase (I) signal and a baseband quadrature (Q) signal and generates a plurality of control signals based on the baseband in-phase signal and the baseband quadrature signal;

a radio-frequency digital to analog converter circuit that receives the local oscillator phase signals and the plurality of control signals and comprises:

a first plurality of switch units that generates a positive radio-frequency signal based on the plurality of local oscillator phase signals and the plurality of control signals, and

a second plurality of switch units that generates a negative radio-frequency signal based on the plurality of local oscillator phase signals and the plurality of control signals,

wherein at least one switch unit of the first or second pluralities of switch units comprises an output port and provides at least a portion of the positive radio-frequency output signal or at least a portion of the negative radio-frequency output signal at the output port, wherein the control circuit is configured to direct the at least one switch unit to encode the baseband in-phase signal and the baseband quadrature signal by selecting a local oscillator phase signal of the local oscillator phase signals based on at least a first control signal of the plurality of control signals and by selecting one of a first voltage, a second voltage, or ground based on at least a second control signal of the plurality of control signals; and

a power combiner circuit that generates a radio-frequency output signal based on a combination of the positive radio-frequency signal from the first plurality of switch units and the negative radio-frequency signal from the second plurality of switch units.

2 . The digital to analog signal conversion system of claim 1 , wherein the power combiner circuit is configured to implement a sum of a first portion of the positive radio-frequency signal and a corresponding first portion of the negative radio-frequency signal when selected local oscillator phase signals have an anti-phase relationship with each other and to implement a difference of a second portion of the positive radio-frequency signal and a corresponding second portion of the negative radio-frequency signal when the selected local oscillator phase signals have an in-phase relationship with each other.

3 . The digital to analog signal conversion system of claim 1 , wherein the first voltage is a power of two of the second voltage.

4 . The digital to analog signal conversion system of claim 3 , wherein the at least one switch unit further comprises:

a selection circuit that receives the at least a second control signal and connects only one of the first voltage, the second voltage, or ground to the output port.

5 . The digital to analog signal conversion system of claim 4 , wherein the control circuit further comprises:

a comparator that compares a first number associated with the in-phase signal with a second number associated with the baseband quadrature signal to determine a greater number of the baseband in-phase and baseband quadrature signals and a smaller number of the baseband in-phase and baseband quadrature signals; and

wherein the control circuit is further configured to:

determine whether the greater number of the baseband in-phase and baseband quadrature signals is an even or an odd number and whether the smaller number of the baseband in-phase and baseband quadrature signals is an even or an odd number,

in response to determining that the greater number of the baseband in-phase and baseband quadrature signals is an odd number:

direct N switch units of the first plurality of switch units and corresponding N switch units of the second plurality of switch units to connect the second voltage to the output port, wherein N is equal to an integer division of the greater number of the baseband in-phase and baseband quadrature signals by two; and

direct another switch unit of the first plurality of switch units and a corresponding other switch unit of the second plurality of switch units to connect the first voltage to the output port;

in response to determining that the greater number of the baseband in-phase and baseband quadrature signals is an even number and that the smaller number of the baseband in-phase and baseband quadrature signals is an even number:

direct N switch units of the first plurality of switch units and corresponding N switch units of the second plurality of switch units to connect the second voltage to the output port, wherein N is equal to an integer division of the greater number of the baseband in-phase and baseband quadrature signals by two;

in response to determining that the greater number of the baseband in-phase and baseband quadrature signals is an even number and that the smaller number of the baseband in-phase and baseband quadrature signals is an odd number:

direct (N−1) switch units of the first plurality of switch units and corresponding (N−1) switch units of the second plurality of switch units to connect the second voltage to the output port, wherein N is equal to an integer division of the greater number of the baseband in-phase and baseband quadrature signals by two; and

direct two other switch units of the first plurality of switch units and corresponding two other switch units of the second plurality of switch units to connect the first voltage to the output port; and

direct all remaining switch units of the first plurality of switch units and all remaining corresponding switch units of the second plurality of switch units to connect ground to the output port.

6 . The digital to analog signal conversion system of claim 1 , wherein the local oscillator generates the plurality of local oscillator phase signals as four local oscillator phase signals, each one of the four local oscillator phase signals having a 25% duty cycle.

7 . The digital to analog signal conversion system of claim 6 , wherein a second, third, and fourth local oscillator phase signal of the four local oscillator phase signals are phase-shifted by 90 degrees, 180 degrees, and 270 degrees, respectively, relative to a first local oscillator phase signal of the four local oscillator phase signals.

8 . The digital to analog signal conversion system of claim 7 , wherein the control circuit is further configured to direct the at least one switch unit to encode the baseband in-phase signal by selecting between the first and third local oscillator phase signals and to encode the baseband quadrature signal by selecting between the second and fourth local oscillator phase signals.

9 . The digital to analog signal conversion system of claim 7 , wherein each switch unit of the first plurality of switch units encodes a positive portion of the baseband in-phase signal and a corresponding positive portion of the baseband quadrature signal, and wherein the control circuit is configured to direct each switch unit of the first plurality of switch units to encode the positive portion of the baseband in-phase signal by selecting the first local oscillator phase signal and to encode the corresponding first portion of the baseband quadrature signal by selecting the second local oscillator phase signal.

10 . The digital to analog signal conversion system of claim 9 , wherein the control circuit further comprises:

a comparator that compares a first number associated with the baseband in-phase signal with a second number associated with the baseband quadrature signal to determine a greater number of the baseband in-phase and baseband quadrature signals; and

wherein the control circuit is further configured to:

direct N switch units of the first plurality of switch units and corresponding N switch units of the second plurality of switch units to connect only the second voltage to the output port,

direct M switch units of the first plurality of switch units and corresponding M switch units of the second plurality of switch units to connect only the first voltage to the output port, wherein (2N+M) is equal to the greater number of the baseband in-phase and baseband quadrature signals and (N+M) is smaller than or equal to a number of switch units in the first plurality of switch units,

direct remaining switch units of the first plurality of switch units and corresponding remaining switch units of the second plurality of switch units to connect only ground to the output port,

direct I switch units of the N switch units of the second plurality of switch units and J switch units of the M switch units of the second plurality of switch units to encode the negative portion of the baseband in-phase signal by selecting the third local oscillator phase signal and direct switch units other than the I and J switch units to encode the negative portion of the baseband in-phase signal by selecting the first local oscillator phase signal, wherein (2I+J) is equal to the first number associated with the baseband in-phase signal, and

direct K switch units of the N switch units of the second plurality of switch units and L switch units of the M switch units of the second plurality of switch units to encode the negative portion of the baseband quadrature signal by selecting the fourth local oscillator phase signal and direct switch units other than the K and L switch units to encode the negative portion of the baseband quadrature signal by selecting the second local oscillator phase signal, wherein (2K+L) is equal to the second number associated with the baseband quadrature signal.

11 . A control circuit for a digital to analog signal conversion system having a local oscillator that generates four local oscillator phase signals that have a 25% duty cycle each and that are phase-shifted by 90 degrees relative to each other, a radio-frequency digital to analog converter circuit with a first plurality of switch units that generates a positive radio-frequency signal and a second plurality of switch units that generates a negative radio-frequency signal, and a power combiner circuit that generates a radio-frequency output signal based on a combination of the positive radio-frequency signal and the negative radio-frequency signal, comprising:

a first input port that receives a baseband in-phase signal;

a second input port that receives a baseband quadrature signal;

a local oscillator phase signal selector circuit that is configured to generate first control signals that select for each switch unit of the first and second pluralities of switch units one of the four oscillator signals for encoding the baseband in-phase signal and another one of the four oscillator signals for encoding the baseband quadrature signal; and

a voltage selector circuit that is configured to generate second control signals that select for each switch unit of the first and second pluralities of switch units to connect a single one of a first voltage, a second voltage, or ground to an output port of the respective switch unit based on the baseband in-phase signal and the baseband quadrature signal, wherein the second voltage is twice the first voltage.

12 . The control circuit of claim 11 , further comprising:

a comparator that compares a first number associated with the baseband in-phase signal with a second number associated with the baseband quadrature signal to determine a greater number of the baseband in-phase and baseband quadrature signals and a smaller number of the baseband in-phase and baseband quadrature signals.

13 . The control circuit of claim 12 , wherein the voltage selector circuit is further configured to:

determine whether the greater number of the baseband in-phase and baseband quadrature signals is an even or an odd number and whether the smaller number of the baseband in-phase and baseband quadrature signals is an even or an odd number;

in response to determining that the greater number of the baseband in-phase and baseband quadrature signals is an odd number:

generate N control signals of the second control signals to direct N switch units of the first plurality of switch units and corresponding N switch units of the second plurality of switch units to connect the second voltage to the output port, wherein N is equal to an integer division of the greater number of the baseband in-phase and baseband quadrature signals by two; and

generate another control signal of the second control signals to direct another switch unit of the first plurality of switch units and a corresponding other switch unit of the second plurality of switch units to connect the first voltage to the output port;

in response to determining that the greater number of the baseband in-phase and baseband quadrature signals is an even number and that the smaller number of the baseband in-phase and baseband quadrature signals is an even number:

generate N control signals of the second control signals to direct N switch units of the first plurality of switch units and corresponding N switch units of the second plurality of switch units to connect the second voltage to the output port, wherein N is equal to an integer division of the greater number of the baseband in-phase and baseband quadrature signals by two;

in response to determining that the greater number of the baseband in-phase and baseband quadrature signals is an even number and that the smaller number of the baseband in-phase and baseband quadrature signals is an odd number:

generate (N−1) control signals of the second control signals to direct (N−1) switch units of the first plurality of switch units and corresponding (N−1) switch units of the second plurality of switch units to connect the second voltage to the output port, wherein N is equal to an integer division of the greater number of the baseband in-phase and baseband quadrature signals by two; and

generate two other control signals of the second control signals to direct two other switch units of the first plurality of switch units and corresponding two other switch units of the second plurality of switch units to connect the first voltage to the output port; and

generate all remaining control signals of the second control signals to direct all remaining switch units of the first plurality of switch units and all remaining corresponding switch units of the second plurality of switch units to connect ground to the output port.

14 . The control circuit of claim 11 , wherein the local oscillator phase signal selector circuit is configured to generate first control signals such that the first control signals direct each switch unit of the first and second pluralities of switch units to encode the baseband in-phase signal by selecting between two local oscillator phase signals of the four local oscillator phase signals that are phase-shifted by 180 degrees relative to each other and to encode the baseband quadrature signal by selecting between two other local oscillator phase signals of the four local oscillator phase signals that are phase-shifted by 180 degrees relative to each other and by 90 degrees relative to the two local oscillator phase signals.

15 . The control circuit of claim 14 , wherein the local oscillator phase signal selector circuit is configured to further generate first control signals such that the first control signals direct a switch unit of the first plurality of switch units and a corresponding switch unit of the second plurality of switch units to select a same local oscillator phase signal of the four local oscillator phase signals to cancel contribution of the switch unit and the corresponding switch unit to the radio-frequency output of the baseband in-phase signal and/or the baseband quadrature signal.

16 . A method of operating a digital to analog signal conversion system having a local oscillator, a control circuit, a radio-frequency digital to analog converter circuit with first and second pluralities of switch units, and a power combiner circuit, comprising:

using the local oscillator to generate a plurality of local oscillator phase signals;

receiving a baseband in-phase (I) signal and a baseband quadrature (Q) signal at the control circuit;

generating, with the control circuit, a plurality of control signals based on the baseband in-phase signal and the baseband quadrature signal;

receiving the local oscillator phase signals and the plurality of control signals at the radio-frequency digital to analog converter circuit;

generating a positive radio-frequency signal of the baseband in-phase signal and the baseband quadrature signal in the first plurality of switch units and a negative radio-frequency signal of the baseband in-phase signal and the baseband quadrature signal in the second plurality of switch units by:

selecting in first switch units of the first plurality of switch units and corresponding second switch units in the second plurality of switch units one of a first voltage, a second voltage, or ground based on at least a first control signal of the plurality of control signals,

selecting, in the first switch units of the first plurality of switch units, two local oscillator phase signals of the local oscillator phase signals based on at least a second control signal of the plurality of control signals, and

selecting, in the second switch units of the second plurality of switch units, two local oscillator phase signals of the local oscillator phase signals based on at least a third control signal of the plurality of control signals; and

generating, with the power combiner circuit, a radio-frequency output signal based on a combination of the positive radio-frequency signal from the first plurality of switch units and the negative radio-frequency signal from the second plurality of switch units.

17 . The method of claim 16 , further comprising:

comparing a first number associated with the baseband in-phase signal with a second number associated with the baseband quadrature signal to determine a greater number of the baseband in-phase and baseband quadrature signals and a smaller number of the baseband in-phase and baseband quadrature signals.

18 . The method of claim 17 , further comprising:

determining whether the greater number of the baseband in-phase and baseband quadrature signals is an even or an odd number and whether the smaller number of the baseband in-phase and baseband quadrature signals is an even or an odd number;

in response to determining that the greater number of the baseband in-phase and baseband quadrature signals is an odd number:

selecting the second voltage in N of the first switch units of the first plurality of switch units and corresponding N of the second switch units of the second plurality of switch units, wherein N is equal to an integer division of the greater number of the baseband in-phase and baseband quadrature signals by two; and

selecting the first voltage in another one of the first switch units of the first plurality of switch units and a corresponding other one of the second switch units of the second plurality of switch units;

in response to determining that the greater number of the baseband in-phase and baseband quadrature signals is an even number and that the smaller number of the baseband in-phase and baseband quadrature signals is an even number:

selecting the second voltage in N of the first switch units of the first plurality of switch units and corresponding N of the second switch units of the second plurality of switch units, wherein N is equal to an integer division of the greater number of the baseband in-phase and baseband quadrature signals by two;

in response to determining that the greater number of the baseband in-phase and baseband quadrature signals is an even number and that the smaller number of the baseband in-phase and baseband quadrature signals is an odd number:

selecting the second voltage in (N−1) of the first switch units of the first plurality of switch units and corresponding (N−1) of the second switch units of the second plurality of switch units, wherein N is equal to an integer division of the greater number of the baseband in-phase and baseband quadrature signals by two; and

selecting the first voltage in two other ones of the first switch units of the first plurality of switch units and corresponding two other ones of the second switch units of the second plurality of switch units; and

selecting ground in all remaining ones of the first switch units of the first plurality of switch units and all corresponding remaining ones of the second switch units of the second plurality of switch units.

19 . The method of claim 16 , further comprising:

using the local oscillator to generate the plurality of local oscillator phase signals as four local oscillator phase signals that have a 25% duty cycle each and that are phase-shifted by 90 degrees relative to each other; and

generating, with the power combiner circuit, the radio-frequency output signal by:

implementing a sum of a first portion of the positive radio-frequency signal and a corresponding first portion of the negative radio-frequency signal when selected local oscillator phase signals have an anti-phase relationship with each other, and

implementing a difference of a second portion of the positive radio-frequency signal and a corresponding second portion of the negative radio-frequency signal when the selected local oscillator phase signals have an in-phase relationship with each other.

20 . The method of claim 19 , wherein generating, with the control circuit, the plurality of control signals based on the baseband in-phase signal and the baseband quadrature signal further comprises:

generating first control signals that direct first and second switch units to encode the baseband in-phase signal by selecting between two local oscillator phase signals of the four local oscillator phase signals that are phase-shifted by 180 degrees relative to each other and to encode the baseband quadrature signal by selecting between two other local oscillator phase signals of the four local oscillator phase signals that are phase-shifted by 180 degrees relative to each other and by 90 degrees relative to the two local oscillator phase signals.

Assignments (1)

Continuity (1)

References Cited (20)