Transmitter and method for transmission control in a technique of delta sigma modulating

Patent metadata

Field	Value
Publication number	US-9748983-B2
Application number	US-201415023719-A
Country	US
Kind code	B2
Filing date	Jun 3, 2014
Priority date	Sep 30, 2013
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

A transmitter according to the present invention includes: a baseband amplitude value distribution processor ( 90 ) for changing a distribution of an amplitude value of a baseband signal based on a control signal that has been input and outputting the baseband signal as an output signal; a digital transmitter ( 91 ) that ΔΣ modulates the output signal and transmits the modulated signal; an in-band distortion measurement unit ( 92 ) for measuring an in-band distortion amount of the output signal; an amplitude value distribution measurement unit ( 93 ) for calculating an amplitude value distribution of the output signal; a sideband distortion prediction unit ( 94 ) for predicting a sideband distortion amount occurring in the output signal by the digital transmitter ( 91 ) from the calculated amplitude value distribution; and a baseband processing controller ( 95 ) for adjusting the control signal based on the measured in-band distortion amount and the sideband distortion amount and outputting the adjusted signal.

First claim

The invention claimed is:

1. A transmitter comprising:
a baseband amplitude value distribution processor that changes a distribution of an amplitude value of a baseband signal based on a control signal that has been input and outputs the baseband signal as an output signal;
a digital transmitter that ΔΣ modulates the output signal of the baseband amplitude value distribution processor and transmits the modulated signal;
an in-band distortion measurer that measures an in-band distortion amount of the output signal of the baseband amplitude value distribution processor;
an amplitude value distribution measurer that calculates an amplitude value distribution of the output signal of the baseband amplitude value distribution processor;
a sideband distortion predictor that predicts a sideband distortion amount occurring in the output signal in the digital transmitter from the amplitude value distribution calculated in the amplitude value distribution measurer; and
a baseband processing controller that adjusts the control signal to be input to the baseband amplitude value distribution processor based on the in-band distortion amount measured in the in-band distortion measurer and the sideband distortion amount predicted in the sideband distortion predictor and outputs the adjusted control signal,
wherein the sideband distortion predictor calculates the sideband distortion amount using a correlation of the amplitude value of the output signal and the sideband distortion amount obtained by measuring changes in the amplitude value of the output signal to be input to the digital transmitter and changes in the sideband distortion amount of the modulated signal to be output from the digital transmitter.

2. The transmitter according to claim 1 , further comprising a power efficiency predictor that predicts a power efficiency of the digital transmitter from the amplitude value distribution calculated in the amplitude value distribution measurer, wherein:
the digital transmitter performs the ΔΣ modulation on the output signal of the baseband amplitude value distribution processor and amplifies the signal that has been ΔΣ modulated,
the power efficiency predictor calculates a prediction value of the power efficiency using the correlation of the amplitude value of the signal and the power efficiency obtained by measuring changes in the amplitude value of the signal to be input to the digital transmitter and changes in the power efficiency in the digital transmitter when the signal is processed and outputs the prediction value to the baseband processing controller, and
the baseband processing controller further adjusts the control signal based on the prediction value of the power efficiency output from the power efficiency predictor.

3. The transmitter according to claim 1 , wherein the baseband amplitude value distribution processor changes the amplitude value distribution of the output signal by at least one of Crest Factor Reduction (CFR) and Vector Hole Punch (VHP) and outputs a resulting signal.

4. The transmitter according to claim 3 , wherein the baseband processing controller changes at least one threshold of the CFR and the VHP of the baseband amplitude value distribution processor as the adjustment of the control signal.

5. The transmitter according to claim 2 , wherein the power efficiency predictor acquires the power efficiency in each amplitude value based on the correlation of the amplitude value of the signal and the power efficiency, weights each power efficiency that has been acquired by the amplitude value distribution calculated in the amplitude value distribution measurer and integrates a resultant value to thereby calculate the prediction value of the power efficiency of the digital transmitter.

6. The transmitter according to claim 1 , wherein the sideband distortion predictor acquires the sideband distortion in each amplitude value based on the correlation of the amplitude value of the signal and the sideband distortion amount, weights each sideband distortion that has been acquired by the amplitude value distribution calculated in the amplitude value distribution measurer and integrates a resultant value to thereby calculate the sideband distortion amount occurring in the output signal in the digital transmitter.

7. The transmitter according to claim 1 , wherein the digital transmitter comprises a ΔΣ modulator that receives an amplitude signal and a phase signal extracted from two orthogonal signals as the output signal, ΔΣ modulates the amplitude signal using the phase signal as a clock signal and outputs the modulated signal as the output signal, and a multiplier that multiplies the output signal of the ΔΣ modulator by the phase signal to generate a pulse signal.

8. The transmitter according to claim 1 , wherein the digital transmitter comprises two ΔΣ modulators that receive two orthogonal signals as the output signal, ΔΣ modulate the two orthogonal signals, and output the modulated signal as the output signal, a frequency converter that up-converts the output signal of the two ΔΣ modulators into a frequency of a desired radio signal and outputs the up-converted signal, and an adder that adds the output signal of the frequency converter.

9. A transmission control method comprising:
changing a distribution of an amplitude value of a baseband signal based on a control signal that has been input and outputting the baseband signal as an output signal;
ΔΣ modulating the output signal that has been output and transmitting the modulated signal by a digital transmitter;
measuring an in-band distortion amount of the output signal that has been output;
calculating an amplitude value distribution of the output signal that has been output;
predicting a sideband distortion amount occurring in the output signal by the ΔΣ modulation from the amplitude value distribution that has been calculated;
adjusting the control signal based on the in-band distortion amount that has been measured and the sideband distortion amount that has been predicted and outputting the control signal; and
calculating the sideband distortion amount using a correlation of the amplitude value of the output signal and the sideband distortion amount obtained by measuring changes in the amplitude value of the output signal to be input to the digital transmitter and changes in the sideband distortion amount of the modulated signal to be output from the digital transmitter.

Assignees

• Nec Corp

Inventors

• Tanio Masaaki

Classifications

• H03F2200/336

  A I/Q, i.e. phase quadrature, modulator or demodulator being used in an amplifying circuit · CPC title

• H03F2200/408

  the output amplifying stage of an amplifier comprising three power stages · CPC title

• H03F3/3022

  CMOS common source output SEPP amplifiers (H03F3/3008 takes precedence) · CPC title

• H03F2200/331

  Sigma delta modulation being used in an amplifying circuit · CPC title

• H03F3/245

  with semiconductor devices only · CPC title