Back to results
US 8,509,294 B2Granted
Signal generator, signal generating system, and signal generating method
AssigneeAnritsu Corporation
InventorsShinichi Ito, Tatsuro Hanaya, Jun Ono
Life of this patent
Estimating the term…
Abstract
To provide a signal generator, a signal generating system, and a signal generating method capable of repeatedly generating an arbitrary waveform and making the phases of the head and tail of the generated waveform continuous with each other, without changing the frequency of the waveform. A signal generator (10, 11, 12) includes phase shift means (30) that receives waveform data which is repeatedly output n times, shifts the phase of each sample data item in an n-th waveform data item by a phase shift amount φn corresponding to the number of times n the waveform data is repeatedly output, and outputs the waveform data to D/A conversion means.
Claims13
A signal generator for testing a wireless communication device comprising:
- waveform data storage means for storing waveform data of a digital baseband signal including M sample data items and repeatedly and continuously outputting the waveform data;
- digital-to-analog conversion means for performing digital-analog conversion on the waveform data;
- frequency conversion means for performing frequency conversion on the digital-analog-converted baseband signal using a carrier signal with a predetermined frequency and outputting the frequency-converted signal as an RF test signal for testing the wireless communication device;
- and
- phase shift means that receives the waveform data which is repeatedly output n times from the waveform data storage means, shifts the phase of each sample data item in an n-th waveform data item by a phase shift amount φn corresponding to the number of times n the waveform data is repeatedly output, and outputs the waveform data to the digital-to-analog conversion means,
- wherein the phase shift amount φn is calculated from a reference phase difference θ, which is a phase difference between an (n−1)-th waveform data item and the n-th waveform data item, and the number of times n the waveform data is repeatedly output in order to obtain a continuous phase change between the tail of the (n−1)-th waveform data item and the head of the n-th waveform data item, and
- wherein the sample data items of the waveform data are a complex I-phase sample data item and a complex Q-phase sample data item, and
- the phase shift means includes:
- phase shift amount calculating means for obtaining the phase shift amount φn from the reference phase difference θ and the number n of times the waveform data is repeatedly output, and outputting a first phase shift data item represented by cos φn and a second phase shift data item represented by sin φn;
- a first multiplier which multiplies the first phase shift data item by the I-phase sample data item output from the waveform data storage means and outputs;
- a second multiplier which multiplies the first phase shift data item by the Q-phase sample data item output from the waveform data storage means and outputs;
- a third multiplier which multiplies the second phase shift data item by the Q-phase sample data item output from the waveform data storage means and outputs;
- a fourth multiplier which multiplies the second phase shift data item by the I-phase sample data item output from the waveform data storage means and outputs;
- a first calculator which subtracts the output of the third multiplier from the output of the first multiplier and outputs to the digital-to-analog conversion means;
- and
- a second calculator which adds the output of the second multiplier and the output of the fourth multiplier and outputs to the digital-to-analog conversion means.
13 more elements
A signal generating method for testing a wireless communication device comprising:
- a step of repeatedly and continuously outputting waveform data of a digital baseband signal including M sample data items;
- a step of performing digital-analog conversion on the waveform data;
- a step of performing frequency conversion on the digital-analog-converted baseband signal using a carrier signal with a predetermined frequency and outputting the frequency-converted signal as an RF test signal for testing the wireless communication device;
- a step of, when the number of times the waveform data is repeatedly output is n, calculating a phase shift amount φn corresponding to the number of times n the waveform data is repeatedly output;
- and
- a step of shifting the phase of each sample data item in an n-th waveform data item by the phase shift amount φn when the waveform data which is repeatedly output n times is received before the digital-analog conversion step,
- wherein the phase shift amount φn is calculated from a reference phase difference θ, which is a phase difference between an (n−1)-th waveform data item and the n-th waveform data item, and the number of times n the waveform data is repeatedly output in order to obtain a continuous phase change between the tail of the (n−1)-th waveform data item and the head of the n-th waveform data item, and
- wherein the sample data items of the waveform data are a complex I-phase sample data item and a complex Q-phase sample data item, and
- the step of shifting the phase includes:
- a step of obtaining the phase shift amount φn from the reference phase difference θ and the number n of times the waveform data is repeatedly output, and outputting a first phase shift data item represented by cos φn and a second phase shift data item represented by sin φn;
- a first multiplying step in which the first phase shift data item is multiplied by the I-phase sample data item of the waveform data output in the step of outputting the waveform data;
- a second multiplying step in which the first phase shift data item is multiplied by the Q-phase sample data item of the waveform data output in the step of outputting the waveform data;
- a third multiplying step in which the second phase shift data item is multiplied by the Q-phase sample data item of the waveform data output in the step of outputting the waveform data;
- a fourth multiplying step in which the second phase shift data item is multiplied by the I-phase sample data item of the waveform data output in the step of outputting the waveform data;
- a first calculating step in which a multiplying result of the third multiplying step is subtracted from a multiplying result of the first multiplying step;
- and
- a second calculating step in which a multiplying result of the second multiplying step is added to a multiplying result of the forth multiplying step,
- wherein, in the step of performing digital-to-analog conversion, calculating results of the first calculating step and the second calculating step are subjected to digital-analog conversion, respectively.
15 more elements
Dependencies are inferred from the claim text.