Signal generation circuit

A signal generation circuit comprising:

• at least one control voltage source circuit that generates a control voltage having one of a plurality of predetermined voltage values, in accordance with an inputted control signal;
• at least one reference voltage source circuit that generates a plurality of predetermined reference voltages;
• a first folding circuit that generates a first output signal based on differences between the control voltage and the plurality of reference voltages, the first output signal having a signal level corresponding to a predetermined phase of a sine wave, and
• a second folding circuit that generates a second output signal based on differences between the control voltage and the plurality of reference voltages, the second output signal having a signal level corresponding to a predetermined phase of a cosine wave,
• wherein the control voltage source circuit comprises a parallel circuit of a plurality of first constant current sources, each of the first constant current sources being turned on or off in accordance with the control signal,
• wherein the first folding circuit comprises:
• a first differential amplifier that compares the control voltage with a first reference voltage to generate a first differential output signal;
• a second differential amplifier that compares the control voltage with a second reference voltage higher than the first reference voltage to generate a second differential output signal;
• and
• a third differential amplifier that compares the control voltage with a third reference voltage higher than the second reference voltage to generate a third differential output signal,
• wherein the second folding circuit comprises:
• a fourth differential amplifier that compares the control voltage with a fourth reference voltage to generate a fourth differential output signal;
• a fifth differential amplifier that compares the control voltage with a fifth reference voltage higher than the fourth reference voltage to generate a fifth differential output signal;
• and
• a sixth differential amplifier that compares the control voltage with a sixth reference voltage higher than the fifth reference voltage to generate a sixth differential output signal,
• wherein the first output signal is a sum of the first and third differential output signals and an inverted signal of the second differential output signal,
• wherein the second output signal is a sum of the fourth and sixth differential output signals and an inverted signal of the fifth differential output signal,
• wherein the at least one control voltage source circuit includes:
• a first control voltage source circuit that generates and supplies a first control voltage to the first to third differential amplifiers, and
• a second control voltage source circuit that generates and supplies a second control voltage to the fourth to sixth differential amplifiers, the first and second control voltages having a voltage difference that is constant modulo a difference between a maximum and a minimum of the first control voltage, and
• wherein the fourth to sixth reference voltages are equal to the first to third reference voltages, respectively.

A signal generation circuit comprising:

• a control voltage source circuit that generates a control voltage having one of a plurality of predetermined voltage values, in accordance with an inputted control signal;
• at least one reference voltage source circuit that generates a plurality of predetermined reference voltages;
• a first folding circuit that generates a first output signal based on differences between the control voltage and the plurality of reference voltages, the first output signal having a signal level corresponding to a predetermined phase of a sine wave, and
• a second folding circuit that generates a second output signal based on differences between the control voltage and the plurality of reference voltages, the second output signal having a signal level corresponding to a predetermined phase of a cosine wave,
• wherein the control voltage source circuit comprises a parallel circuit of a plurality of first constant current sources, each of the first constant current sources being turned on or off in accordance with the control signal,
• wherein the first folding circuit comprises:
• a first differential amplifier that compares the control voltage with a first reference voltage to generate a first differential output signal;
• a second differential amplifier that compares the control voltage with a second reference voltage higher than the first reference voltage to generate a second differential output signal;
• and
• a third differential amplifier that compares the control voltage with a third reference voltage higher than the second reference voltage to generate a third differential output signal,
• wherein the second folding circuit comprises:
• a fourth differential amplifier that compares the control voltage with a fourth reference voltage to generate a fourth differential output signal;
• a fifth differential amplifier that compares the control voltage with a fifth reference voltage higher than the fourth reference voltage to generate a fifth differential output signal;
• and
• a sixth differential amplifier that compares the control voltage with a sixth reference voltage higher than the fifth reference voltage to generate a sixth differential output signal,
• wherein the first output signal is a sum of the first and third differential output signals and an inverted signal of the second differential output signal,
• wherein the second output signal is a sum of the fourth and sixth differential output signals and an inverted signal of the fifth differential output signal,
• wherein the control voltage source circuit supplies one common control voltage to the first to sixth differential amplifiers,
• wherein the first to sixth reference voltages are different from each other,
• wherein the at least one reference voltage source circuit includes:
• a first reference voltage source circuit that generates the first and sixth reference voltages,
• a second reference voltage source circuit that generates the second and fifth reference voltages, and
• a third reference voltage source circuit that generates the third and fourth reference voltages,
• wherein the first reference voltage source circuit comprises a parallel circuit of a plurality of second constant current sources, each of the second constant current sources being connected to one of the first and sixth differential amplifiers in accordance with a reference voltage to be generated,
• wherein the second reference voltage source circuit comprises a parallel circuit of a plurality of third constant current sources, each of the third constant current sources being connected to one of the second and fifth differential amplifiers in accordance with a reference voltage to be generated,
• wherein the third reference voltage source circuit comprises a parallel circuit of a plurality of fourth constant current sources, each of the fourth constant current sources being connected to one of the third and fourth differential amplifiers in accordance with a reference voltage to be generated, and
• wherein each of the first to third reference voltage source circuits has components and a layout at least partially identical to components and a layout of the control voltage source circuit.

A phase shifter comprising:

• a signal generation circuit that generates a first output signal and a second output signal;
• a quadrature splitter that splits an input signal into an in-phase signal and a quadrature-phase signal;
• a first multiplier that multiplies the in-phase signal by the second output signal of the signal generation circuit to generate a first multiplication signal;
• a second multiplier that multiplies the quadrature-phase signal by the first output signal of the signal generation circuit to generate a second multiplication signal;
• and
• a combiner that combines the first multiplication signal and the second multiplication signal with each other,
• wherein the signal generation circuit comprises:
• at least one control voltage source circuit that generates a control voltage having one of a plurality of predetermined voltage values, in accordance with an inputted control signal;
• at least one reference voltage source circuit that generates a plurality of predetermined reference voltages;
• a first folding circuit that generates the first output signal based on differences between the control voltage and the plurality of reference voltages, the first output signal having a signal level corresponding to a predetermined phase of a sine wave, and
• a second folding circuit that generates the second output signal based on differences between the control voltage and the plurality of reference voltages, the second output signal having a signal level corresponding to a predetermined phase of a cosine wave,
• wherein the control voltage source circuit comprises a parallel circuit of a plurality of first constant current sources, each of the first constant current sources being turned on or off in accordance with the control signal,
• wherein the first folding circuit comprises:
• a first differential amplifier that compares the control voltage with a first reference voltage to generate a first differential output signal;
• a second differential amplifier that compares the control voltage with a second reference voltage higher than the first reference voltage to generate a second differential output signal;
• and
• a third differential amplifier that compares the control voltage with a third reference voltage higher than the second reference voltage to generate a third differential output signal,
• wherein the second folding circuit comprises:
• a fourth differential amplifier that compares the control voltage with a fourth reference voltage to generate a fourth differential output signal;
• a fifth differential amplifier that compares the control voltage with a fifth reference voltage higher than the fourth reference voltage to generate a fifth differential output signal;
• and
• a sixth differential amplifier that compares the control voltage with a sixth reference voltage higher than the fifth reference voltage to generate a sixth differential output signal,
• wherein the first output signal is a sum of the first and third differential output signals and an inverted signal of the second differential output signal,
• wherein the second output signal is a sum of the fourth and sixth differential output signals and an inverted signal of the fifth differential output signal,
• wherein the at least one control voltage source circuit includes:
• a first control voltage source circuit that generates and supplies a first control voltage to the first to third differential amplifiers, and
• a second control voltage source circuit that generates and supplies a second control voltage to the fourth to sixth differential amplifiers, the first and second control voltages having a voltage difference that is constant modulo a difference between a maximum and a minimum of the first control voltage, and
• wherein the fourth to sixth reference voltages are equal to the first to third reference voltages, respectively.