JP2005039725A - Data converter and transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data converter for amplifying a signal with large peak factor without generating distortion and with high power efficiency. <P>SOLUTION: When a first piece of amplitude data is larger than a predetermined value, an amplitude data generation means 104 generates a second piece of amplitude data having a first data value equal to or more than the predetermined value, a phase data generation means 104 generates a new piece of phase data to first and second output signals including the second piece of amplitude data having the first data value by decomposing an input signal. When the second piece of amplitude data is smaller than the predetermined value, the amplitude data generation means 104 generates the second piece of amplitude data having a second data value smaller than the first data value and the phase data generation means 104 generates new pieces of phase data to the first and second output signals including the second piece of amplitude data having the second data value by decomposing the input signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a data conversion apparatus, and more specifically, a data conversion apparatus for converting an input signal including first amplitude data and first phase data into first and second output signals. It is invention regarding.

  In a conventional transmitter (hereinafter referred to as a first conventional transmitter), a modulated signal is amplified in order to output a signal with a large electric power from an antenna. However, when a signal with a large fluctuation in the envelope strength, that is, a signal with a large peak factor is amplified, signal distortion caused by the nonlinearity of the amplifier occurs at the so-called peak portion where the envelope strength is large. End up. For this reason, the amplifier needs to amplify the signal at a power sufficiently smaller than the saturation power.

  However, when the amplifier is operated with a power smaller than the saturated power, there is a problem that the power efficiency of the amplifier becomes low and the power consumption increases. Therefore, there is a method called LINC (Linear Amplifying using Nonlinear Components) as a method for reducing the power consumption of the amplifier by operating the amplifier with saturated power. Hereinafter, a transmission circuit to which the LINC is applied (hereinafter referred to as a LINC transmission circuit) will be described with reference to the drawings. FIG. 19 is a block diagram showing a configuration of the LINC transmission circuit.

  First, two baseband signals are input to the input terminal 1301. Specifically, the amplitude data V (t) and the phase data θ (t) included in the signal S (t) shown in Expression (1) are input to the input signal 1301 as a baseband signal. Note that the image of the waveform of S (t) shown in the equation (1) is an envelope signal having an intensity that is not constant in time as shown in FIG. Further, ω is an angular frequency.

S (t) = V (t) cos (ωt + θ (t)) (1)
Next, the signal processing unit 1303 converts the input amplitude data V (t) and phase data θ (t) into two sets of baseband signals whose envelope intensity does not change over time. Specifically, the signal processing unit 1303 converts the amplitude data V (t) and the phase data θ (t) into signals S ₁ (t) and S ₂ (t) shown in the equations (2) and (3). The phase data θ (t) + φ (t) and phase data θ (t) −φ (t) included are converted into two baseband signals. Then, the signal processing unit 1303 outputs the phase data θ (t) + φ (t) of S ₁ (t) from the upper signal line to the vector modulator 1304 as a baseband signal, and S ₂ (t) Phase data θ (t) −φ (t) is output from the lower signal line to the vector modulator 1304 as a baseband signal. Note that a relationship of S (t) = S ₁ (t) + S ₂ (t) is established between S (t), S ₁ (t), and S ₂ (t). A in Formula (2) and Formula (3) is a constant. Further, φ (t) is expressed by Equation (4).

S ₁ (t) = A · cos (ωt + θ (t) + φ (t)) (2)
S ₂ (t) = A · cos (ωt + θ (t) −φ (t)) (3)
φ (t) = cos ⁻¹ (V (t) / 2A) (4)
0 ° ≦ φ (t) ≦ 90 °
The vector modulator 1304 that has received the phase data θ (t) + φ (t) and the phase data θ (t) −φ (t) modulates these baseband signals (for example, quadrature modulation), and the equation (2) The signal S ₁ (t) as shown in FIG. 4 is output to the amplifier 1305, and the signal S ₂ (t) as shown in Expression (3) is output to the amplifier 1306. Here, the signals S ₁ (t) and S ₂ (t) shown in the equations (2) and (3) are signals whose envelopes have a constant strength as shown in FIG. It is.

The amplifiers 1305 and 1306 that have acquired the signals S ₁ (t) and S ₂ (t) amplify the amplitude of the acquired signals and output them to the combiner 1307 as shown in FIG.

  Next, the synthesizer 1307 synthesizes the output signals, creates a signal shown in FIG. 20D having a waveform obtained by amplifying the signal S (t) in FIG. Output to. Here, as the combiner 1307, for example, a 3 dB coupler is used. Thereby, the amplified signal is output from the transmission circuit.

Here, the input signals S ₁ (t) and S ₂ (t) to the amplifiers 1305 and 1306 are signals whose envelope strengths do not change with time. Therefore, even if the amplification characteristics of the amplifiers 1305 and 1306 are non-linear, distortion components are not generated at frequencies near the input signals S ₁ (t) and S ₂ (t). Accordingly, high-efficiency amplifiers such as class C, class D, and class E that cannot be used for amplifying a signal whose envelope strength changes with time can be used as amplifiers for transmission circuits. Since such a high efficiency amplifier circuit has high power efficiency, the power consumption of the entire transmission circuit can be reduced.
P. B. Kenington, “High-linearity RF amplifier design”, Arttech House Publishers, USA, 2000, p443.

  However, when the temporal fluctuation of the envelope strength is large, that is, when the peak factor is large, the amplifiers 1305 and 1306 need to operate with sufficiently large power to enable signal amplification even at the peak of the envelope. There is. For this reason, when the instantaneous power from the output terminal 1302 is small, most of the power output from the amplifiers 1305 and 1306 becomes heat at the termination resistor 1308. As a result, overall power consumption increases. The above problem will be described below with reference to the drawings. Here, FIG. 21 is a diagram showing the relationship between the intensity and phase of the signal input to each of the two amplifiers 1305 and 1306 in two cases, when the instantaneous power input is large and when the instantaneous power is small. It is.

Here, when the strength of the envelope is large, the angle between the baseband signal (complex envelope) of S ₁ (t) and the baseband signal of S (t), and S ₂ (t) and S (t ) (T), which is an angle formed by (), is relatively small as shown in FIG. On the other hand, when the strength of the envelope is small, the angle between the baseband signal of S ₁ (t) and the baseband signal of S (t) and the baseband signal of S ₂ (t) and S (t) Φ (t), which is an angle formed with the baseband signal, is relatively large as shown in FIG. Thus, when the strength of the envelope is large, φ (t) becomes large, and when S ₁ (t) and S ₂ (t) are combined by the combiner 1307, a large loss occurs. As a result, the terminal resistor 1308 changes to heat. In the following, the loss is quantitatively evaluated with reference to the drawings, taking the case where the LINC transmission circuit is applied to an OFDM modulated wave as an example. Here, the condition in this example is that QPSK is applied as the primary modulation, the FFT length is 64, 52 subcarriers, and the symbol rate is 20 MHz. FIG. 22 is a diagram showing a complex envelope (IQ signal) of a modulated wave. The vertical axis indicates the intensity of the Q signal, and the horizontal axis indicates the intensity of the I signal. FIG. 23 is a diagram showing a CCDF (complementary cumulative distribution function) of the modulated wave. Specifically, it is a diagram showing how much a signal having a higher intensity than the signal of the average power of the modulated wave is present. Note that the horizontal axis indicates how much dB is higher than the average power, and the vertical axis indicates the existence probability of a signal that is greater than or equal to each intensity.

  Here, as shown in FIG. 22, the intensity of the envelope of the modulated wave is concentrated near the center, and the density becomes sparse as the distance from the center of the figure increases. This indicates that the intensity of the envelope of the modulated wave is concentrated at a relatively small place, and that an envelope having a high intensity sometimes exists. Specifically, as shown in FIG. 23, there is a peak that is about 10 dB larger than the average power of the intensity of the modulated wave envelope. For example, the existence probability of a signal that is 6 dB higher than the average power is about 1 It is a low probability of about%. When such a modulated wave is transmitted by a conventional LINC transmission circuit, even if the efficiency of the amplifier is set to 100%, about 90% is heated by the termination resistor, and the power efficiency is very low.

  Accordingly, an object of the present invention is to provide a data conversion apparatus for enabling an envelope signal having a large peak factor to be amplified with high power efficiency without causing distortion, and a transmission to which the data conversion apparatus is applied. Is to provide a machine.

  In the present invention, each of the first and second output signals includes second amplitude data having the same magnitude, and the determination unit determines whether or not the first amplitude data is greater than a predetermined value. The amplitude data generation unit generates second amplitude data having the first data value when the determination unit determines that the first amplitude data is greater than the predetermined value, and the first amplitude data is determined to be predetermined. When the determination means determines that the value is less than or equal to the value, second amplitude data having a second data value smaller than the first data value is generated, and the phase data generation means When larger than the predetermined value, the input signal is decomposed into first and second output signals including the second amplitude data having the first data value and included in the first output signal. The third phase data and the third output included in the second output signal First and second output signals including second amplitude data having a second data value when the determination means determines that the first amplitude data is equal to or less than a predetermined value. In addition, the input signal is decomposed to generate the second phase data and the third phase data.

  Here, it is desirable that the second data value is ½ of the first data value.

  In the data conversion device, the threshold determination means for determining whether or not the first amplitude data of the input signal is larger than a preset threshold, and the threshold determination means, the first amplitude data is the threshold If it is determined that the amplitude is greater than the threshold value, the first amplitude data may be set to the threshold value and may be further provided with an amplitude limiting unit that outputs the first amplitude data to the determination unit.

  Further, the phase difference between the first phase data and the second phase data and the phase difference between the first phase data and the third phase data are based on the first phase data and the second phase data The angle is preferably equal to the angle between the base and the hypotenuse of a right triangle having a hypotenuse of twice the length.

  Here, the present invention is directed not only to a data converter, but also to a transmitter including the data converter. Specifically, the transmitter includes conversion means for converting the input signal into first and second output signals each including second amplitude data having the same magnitude, and the conversion means includes the first If the determination means determines whether the amplitude data is greater than the predetermined value and the determination means determines that the first amplitude data is greater than the predetermined value, the second having the first data value Amplitude data is generated, and when the determination means determines that the first amplitude data is smaller than a predetermined value, second amplitude data having a second data value smaller than the first data value is generated. When the amplitude data generating means and the first amplitude data are larger than a predetermined value, the input signal is applied to the first and second output signals including the second amplitude data having the first data value. Decomposed and included in the first output signal 2 phase data and third phase data included in the second output signal are generated, and when the determination means determines that the first amplitude data is smaller than a predetermined value, the second data value is Phase data generating means for decomposing the input signal into first and second output signals including the second amplitude data and generating the second phase data and the third phase data; The means generates a first output signal that is amplitude-modulated and phase-modulated based on the second amplitude data generated by the amplitude data generating means and the second phase data generated by the phase data generating means, Based on the second amplitude data generated by the amplitude data generating means and the third phase data generated by the phase data generating means, a second output signal that is amplitude-modulated and angle-modulated is generated, and the first output signal is generated. The amplification means is generated by the modulation means. The amplitude of the first output signal is amplified, the second amplification means amplifies the amplitude of the second output signal generated by the modulation means, and the synthesis means outputs the first output amplified by the first amplification means. The signal and the second output signal amplified by the second amplifying means are synthesized.

  The transmitter corrects the second amplitude data and the second phase data so as to correct the nonlinearity of the first amplifying means, and corrects the nonlinearity of the second amplifying means. It is preferable that the apparatus further comprises data correction means for correcting the second amplitude data and the third phase data.

  In another aspect of the present invention, in the transmitter, the converting means converts the input signal into first and second output signals each including second amplitude data having the same magnitude, and the converting means. Is determined by the determining means for determining whether or not the first amplitude data is greater than a predetermined value, and if the determining means determines that the first amplitude data is greater than the predetermined value, the first data value When the determination means determines that the first amplitude data is smaller than the predetermined value, the second amplitude data having the second data value smaller than the first data value is generated. Amplitude data generating means for generating amplitude data, and when the first amplitude data is larger than a predetermined value, the first and second output signals including the second amplitude data having the first data value , Decompose the input signal and output the first output signal. If the determination means determines that the first amplitude data is smaller than a predetermined value, the second phase data included in the second output data and the third phase data included in the second output signal are generated. Phase data generating means for generating the second phase data and the third phase data by decomposing the input signal into first and second output signals including second amplitude data having a data value of The angle-modulated wave signal generating means generates the angle-modulated first angle-modulated wave signal based on the second phase data generated by the phase data generating means, and the phase data generating means generates Based on the third phase data, an angle-modulated second angle-modulated wave signal is generated, and the first amplitude-modulating means generates the first angle-modulated wave signal generated by the angle-modulated wave signal generating means, Amplitude modulation using the second amplitude data, the first An output signal is generated, and the second amplitude modulation means amplitude-modulates the second angle modulation wave signal generated by the angle modulation wave signal generation means using the second amplitude data, and converts the second output signal into The generating and synthesizing unit synthesizes the first output signal generated by the first amplitude modulating unit and the second output signal generated by the second amplitude modulating unit.

  Here, the first amplitude modulation means and the second amplitude modulation means are constituted by an amplifier including a transistor, and the first angle modulation wave signal is input to the control electrode of the first amplitude modulation means, A voltage corresponding to the data value of the second amplitude data is applied to the conduction electrode of the first amplitude modulation means, and the second angle modulation wave signal is input to the control electrode of the second amplitude modulation means. A voltage corresponding to the data value of the second amplitude data may be applied to the conduction electrode of the second amplitude modulation means. The control electrode is a gate electrode in the case of a MOS transistor, and a base electrode in the case of a bipolar transistor. Further, the conduction electrode is a drain electrode in the case of a MOS transistor, and a collector electrode in the case of a bipolar transistor.

  The first amplitude modulation means and the second amplitude modulation means are constituted by an amplifier including a transistor, and the control electrode of the first amplitude modulation means has a first angle modulation wave signal and a second amplitude. A voltage corresponding to the data value of the data is applied, and a voltage corresponding to the data value of the second angle modulated wave signal and the second amplitude data is applied to the control electrode of the second amplitude modulation means. Good.

  The first amplitude modulation means includes a first amplifier and a second amplifier having a gain smaller than that of the first amplifier, and the second amplitude modulation means includes the third amplifier and the third amplifier. And a fourth amplifier having a gain smaller than that of the first amplifier, and the switch control means sends the first angle-modulated wave signal to the first amplifier when the second amplitude data is the first data value. And the third amplifier amplifies the second angle-modulated wave signal, and the second amplitude data is the second data value, the second amplifier supplies the first angle-modulated wave signal. And the third amplifier amplifies the amplitude of the fourth angle modulated wave signal.

  In addition, the first phase data has a phase larger than the second phase data, and the first phase correction unit is configured such that when the second amplitude data is the first data value, A second phase correction unit that adds a predetermined phase having a magnitude of 0 to 90 ° to the first phase data, subtracts a predetermined phase having a magnitude of 0 to 90 ° from the second phase data. If the second amplitude data is the first data value, a predetermined phase having a magnitude of 0 to 90 ° is subtracted from the phase of the first angle-modulated wave signal to obtain the second angle A predetermined phase having a magnitude of 0 to 90 ° may be added to the phase of the modulated wave signal. Here, the predetermined phase is preferably an angle between the hypotenuse and the base of a right triangle having the first data value as the hypotenuse and the second data value as the base.

  According to the data conversion device of the present invention, an envelope signal having a large peak factor can be amplified with high power efficiency without causing distortion.

  Here, by setting the second data value to ½ of the first data value, switching from the second data value to the first data value is performed by the first output signal and the second output signal. This is performed when the angle between and is 0 °. That is, in the region where the first amplitude data is small, the second output signal, which is a small output in the widest possible region, is used, so that the power consumption of the entire device can be further reduced.

  In addition, when the first amplitude data of the input signal is larger than a preset threshold value, the first amplitude data is limited to the threshold value, so that the very large first amplitude data is obtained. When data is input, the first amplitude data can be cut. As a result, a signal having a strength higher than a predetermined value is not input to the other components, and the upper limit value of the power value of the other components can be reduced, further reducing the power consumption of the entire apparatus. It becomes possible to do.

  Further, according to the transmitter of the present invention, it is possible to amplify an envelope signal having a large peak factor with high power efficiency without causing distortion.

  In particular, by correcting the second amplitude data, the second phase data, and the third phase data so as to correct the nonlinearity of the first amplifier and the second amplifier, the first and second phase data are corrected. It is possible to further reduce distortion generated in the amplifier.

  Also, the transmitter according to another aspect of the present invention can amplify an envelope signal having a large peak factor without causing distortion and with high power efficiency.

  In particular, the first angle modulation wave signal is input to the control electrode of the first amplitude modulation means, and a voltage corresponding to the data value of the second amplitude data is applied to the conduction electrode of the first amplitude modulation means. The second angle modulation wave signal is applied to the control electrode of the second amplitude modulation means, and the voltage corresponding to the data value of the second amplitude data is applied to the conduction electrode of the second amplitude modulation means. Is applied, a signal having a discrete intensity that does not continuously change is input to the first and second amplitude modulation means. As a result, distortion is less likely to occur in the first amplitude modulation means and the second amplitude modulation means.

  In addition, each amplitude modulation means includes two amplifiers having different gains, and the amplifier to be used is switched according to the value of the second amplitude data. Therefore, each amplitude modulation means always has a constant intensity. The input signal is input. As a result, distortion is less likely to occur in each amplitude modulation means.

  Further, when the second amplitude data is the third data value, the second and third phase data are corrected by adding or subtracting a predetermined phase. Thereby, it becomes possible to reduce the discontinuous change of the second and third phase data at the moment when the second amplitude data is switched from the first data value to the second data value. In particular, when the predetermined phase is an angle between the hypotenuse and the base of a right triangle having the first data value as the hypotenuse and the second data value as the base, the second and third phase data Discontinuous changes can be eliminated.

(First embodiment)
Hereinafter, a transmitter to which a data conversion apparatus according to a first embodiment of the present invention is applied will be described with reference to the drawings. The transmitter amplifies and outputs an input signal having the amplitude data and the phase data shown in Expression (1). Here, FIG. 1 is a block diagram showing the overall configuration of the transmitter.

  The transmitter includes an input terminal 101, an output terminal 102, an amplitude limiting unit 103, a signal processing unit 104, a vector modulator 105, a vector modulator 106, an amplifier 107, an amplifier 108, a combiner 109, and a termination resistor 110.

The input terminal 101 receives amplitude data V (t) and phase data θ (t) shown in Expression (1) as baseband signals. The amplitude limiting unit 103 limits the size of the amplitude data V (t) having a size equal to or larger than the threshold value V _max to V _max . In the envelope of the input signal, as shown in FIGS. 22 and 23, the probability that a large peak value appears is low. For example, according to FIG. 23, the signal that is 8 dB larger than the average power of the input signal is about 0.1% of the whole. For this reason, for a signal having an intensity greater than a certain threshold value V _max , even if the peak value is suppressed to V _max , no significant signal deterioration occurs. It should be noted that a relationship of V _max = 2V ₁ is preferably established between V _max and V ₁ . However, V _max <2V ₁ may be sufficient.

The signal processing unit 104 uses a set of amplitude data V (t) and phase data θ (t) output from the amplitude limiting unit 103 as amplitude data V _n , phase data θ (t) + φ (t), and phase. Data θ (t) −φ (t) is converted, amplitude data V _n and phase data θ (t) + φ (t) are output to vector modulator 105, and amplitude data V _n and phase data θ (t) − φ (t) is output to the vector modulator 106. Hereinafter, processing performed by the signal processing unit 104 will be described in detail with reference to the drawings. FIG. 2 is a diagram illustrating a conversion mechanism when the signal processing unit 104 performs data conversion.

The signal processing unit 104 converts the baseband signal of the signal S (t) shown in Expression (1), V (t) and θ (t) into the baseband signal of the signal S ₁ (t) shown in Expression (5), decomposes to V _n and θ and (t) + φ (t) baseband signal of formula signal S ₂ shown in (6) (t), V n and θ and (t) -φ (t).

S ₁ (t) = V _n · cos (ωt + θ (t) + φ (t)) (5)
S ₂ (t) = V _n · cos (ωt + θ (t) −φ (t)) (6)
Here, a relationship of S (t) = S ₁ (t) + S ₂ (t) is established between S (t), S ₁ (t), and S ₂ (t). Also, φ (t) indicates an angle formed by the signal S (t) and the signal S ₁ (t) (or the signal S ₂ (t)), and is expressed by Expression (7).

φ (t) = cos ⁻¹ (V (t) / 2V _n ) (7)
0 ° ≦ φ (t) ≦ 90 °
V _n is a plurality of types of data values (V _{1 to} V _m (V ₁ >...> V _m ) set in advance in the signal processing unit 104, and input amplitude data V (t ) in response to the magnitude, the value of V _n is changed to the. Specifically, the value of V _n is. below is set to a value of the minimum of V _n satisfying V (t) ≦ 2V _n, This switching will be described with reference to FIG. 2 in the case where V _n can take two values of V ₁ and V ₂ .

First, when the magnitude of the input amplitude data V (t) is twice or more than V ₂ , V _n = V ₁ . In this case, as shown in FIG. 2A, φ (t) is cos ⁻¹ (V (t) / 2V ₁ ). On the other hand, when the magnitude of the input V (t) is smaller than twice V ₂ , V _n = V ₂ as shown in FIG. In this case, as shown in FIG. 2A, φ (t) is cos ⁻¹ (V (t) / 2V ₂ ). As described above, in the present embodiment, V _n used varies depending on the magnitude of the amplitude data V (t). Specifically, when the amplitude data V (t) is large, a relatively large V ₁ is used for V _n , and when the amplitude data V (t) is small, a relatively small V ₂ is V Used for _n .

  The vector modulators 105 and 106 modulate the amplitude data and the phase data output from the signal processing unit 104 (for example, quadrature modulation). Amplifiers 107 and 108 amplify the amplitudes of the signals modulated by vector modulators 105 and 106. The combiner 109 combines the signals output from the amplifiers 107 and 108 and outputs the combined signal to the output terminal 102.

  The operation of the transmitter configured as described above will be described below. Each process shown in the present embodiment can be realized by software using a computer, or can be realized by using a dedicated hardware circuit that performs each process.

  First, two baseband signals are input to the input terminal 101. Specifically, the amplitude data V (t) and the phase data θ (t) included in the signal S (t) shown in Expression (1) are input to the input signal 101 as a baseband signal. In addition, the image of the waveform of S (t) shown in Expression (1) is a signal whose envelope intensity is not constant over time as shown in FIG.

  Next, operations performed by the amplitude limiting unit 103 and the signal processing unit 104 will be described with reference to the drawings. FIG. 3 is a flowchart showing operations performed by the amplitude limiting unit 103 and the signal processing unit 104.

  The amplitude limiter 103 that has acquired the amplitude data V (t) and the phase data θ (t) via the input terminal 101 refers to the intensity of the acquired amplitude data V (t) (step S1).

Next, the amplitude limiter 103 determines whether or not the amplitude data V (t) is larger than a preset threshold value V _max (step S2). If V (t) is greater than V _max , the process proceeds to step S3. On the other hand, when V (t) is smaller than V _max, the procedure proceeds to step S4.

When V (t) is larger than V _max , the amplitude limiter 103 sets the magnitude of the amplitude data V (t) to V _max (step S3). Thereafter, the process proceeds to step S4.

  In step S4, the amplitude limiting unit 103 outputs the amplitude data V (t) and the phase data θ (t) to the signal processing unit 104 (step S4). In response, the signal processing unit 104 acquires amplitude data V (t) and phase data θ (t).

The signal processing unit 104 that has acquired the amplitude data V (t) and the phase data θ (t) refers to the acquired amplitude data V (t) (step S5). Next, the signal processing unit 104 determines whether or not the intensity of the amplitude data V (t) is equal to or less than twice the preset intensity of V ₂ (step S6). If V (t) is not 2V ₂ or less, the process proceeds to step S7. On the other hand, if V (t) is 2V ₂ or less, the process proceeds to step S8.

If V (t) is not 2V ₂ or less, the signal processing unit 104 sets V _n to V ₁ , and further sets φ (t) to cos ⁻¹ (V (t) / 2V ₁ ) (step) S7). Thereafter, the signal processing unit 104 outputs V ₁ and θ (t) + φ (t) to the vector modulator 105, and outputs V ₁ and θ (t) −φ (t) to the vector modulator 106. (Step S9).

On the other hand, when V (t) is 2V ₂ or less, the signal processing unit 104 sets V _n to V ₂ and further sets φ (t) to cos ⁻¹ (V (t) / 2V ₂ ). (Step S8). Thereafter, the signal processing unit 104 outputs V ₂ and θ (t) + φ (t) to the vector modulator 105, and outputs V ₂ and θ (t) −φ (t) to the vector modulator 106. (Step S10). This completes the operations of the amplitude limiting unit 103 and the signal processing unit 104. The above process is performed at every predetermined time step (Δt). This process and subsequent modulation and amplification processes are performed simultaneously.

The vector modulator 105 that has acquired V _n and θ (t) + φ (t) from the signal processing unit 104 modulates these data (for example, orthogonal modulation). As a result, the vector modulator 105 outputs a signal S ₁ (t) shown in Expression (5) to the amplifier 107. On the other hand, the vector modulator 106 that has acquired V _n and θ (t) −φ (t) from the signal processing unit 104 modulates (for example, quadrature modulation) these data. As a result, the vector modulator 106 outputs the signal S ₂ (t) shown in Expression (6) to the amplifier 108. Signals S ₁ (t) and S ₂ (t) are waveforms in which the envelope of the angle-modulated signal is switched between V ₁ and V ₂ over time, as shown in FIG. 4 (a). Have

The amplifier 107 that has acquired the envelope signal S ₁ (t) from the vector modulator 105 amplifies the acquired signal S ₁ (t) and outputs the amplified signal S ₁ (t) to the combiner 109. Similarly, the amplifier 108 that acquired the signal S ₂ (t) from the vector modulator 106 amplifies the acquired signal S ₂ (t) and outputs the amplified signal S ₂ (t) to the combiner 109. The waveforms of the signals output from the amplifiers 107 and 108 are obtained by amplifying the signal shown in FIG. 4A as shown in FIG.

Finally, the synthesis unit 109 synthesizes the acquired signals S ₁ (t) and S ₂ (t), and outputs them from the output terminal 102 to the outside. Note that the waveform of the modulation signal created by the synthesis unit 109 is a signal as shown in FIG.

As described above, according to the transmitter to which the data conversion device according to the present embodiment is applied, the signal input to the amplifier is a signal having discretely changing intensity, and thus when the signal is amplified In addition, distortion is unlikely to occur. Specifically, in a conventional transmitter to which LINC is not applied (the first conventional transmitter described first in the background art), the intensity of the envelope signal input to the amplifier continuously changes. It was. Therefore, the amplifier must always have linearity between the maximum value and the minimum value of the envelope signal. On the other hand, in this embodiment, the intensity of the signal input to the amplifier changes only in two stages. Therefore, as long as linearity is established between at least two input intensities, distortion in the amplified signal does not occur. As a result, the transmitter to which the data conversion device according to the present embodiment is applied has an advantage that distortion after amplification is less likely to occur compared to a conventional transmitter. Hereinafter, as in the prior art, the result when the present embodiment is applied to an OFDM modulated wave is shown. FIG. 5 is a diagram showing a complex envelope (IQ signal) of a modulated wave before amplification input to two amplifiers. FIG. 6 is a diagram showing a complex envelope (IQ signal) of a modulated wave after amplification and synthesis. For simplicity, it is assumed that the relationship V ₂ = 2V ₁ is established.

As shown in FIG. 5, it can be seen that there are only two intensities of the envelope signals input to the two amplifiers 107 and 108, ie, an inner circle and an outer circle. This indicates that the signals input to the amplifiers 107 and 108 have only two types of intensity, V ₁ and V ₂ . When such a signal is amplified by the amplifiers 107 and 108 and further synthesized by the synthesizer 109, it has a complex envelope as shown in FIG. Here, comparing FIG. 6 showing the complex envelope after amplification and FIG. 22 showing the complex envelope before amplification, it can be seen that the shapes match each other. That is, even when the modulation and amplification according to the present embodiment are performed, the waveforms of the input signal and the output signal are not changed, indicating that no distortion has occurred.

Further, according to the transmitter to which the data conversion apparatus according to the present embodiment is applied, the amplitude V _{n of} S ₁ (t) and S ₂ (t) changes to multi-stage values, so that power efficiency is improved. To do. This will be described in detail. Conventionally, the amplitudes of S ₁ (t) and S ₂ (t) are always constant, and therefore, when the magnitude of the input amplitude data V (t) decreases, S ₁ (t) and S ₁ The angle between _{2 and} (t) has increased. As a result, there is a problem that components canceling each other between S ₁ (t) and S ₂ (t) become large, and power efficiency deteriorates.

However, in the present embodiment, as described above, the amplitude V _{n of} S ₁ (t) and S ₂ (t) varies in multiple stages according to the magnitude of the input amplitude data V (t). Changes to a value. Therefore, when the magnitude of the input amplitude data V (t) becomes small, V (t) can be expressed using a small amplitude V _n , and S ₁ (t) and S _{1 2 The} angle formed with (t) can be reduced. As a result, the components that cancel each other out between S ₁ (t) and S ₂ (t) can be reduced, and the power efficiency can be improved. Hereinafter, as in the prior art, the result when the present embodiment is applied to an OFDM modulated wave is shown. FIG. 7 shows the existence probabilities at each intensity of the envelope signals of S ₁ (t) and S ₂ (t). The horizontal axis indicates the intensity of the envelope signal, and the vertical axis indicates the existence probability of the envelope signal. In the present embodiment, S ₁ (t) and S ₂ (t) can take binary values of V ₁ and V ₂ . Therefore, in the graph of FIG. 7, two peaks appear, the left peak indicates the existence probability of the envelope signal having the intensity of V ₂ , and the right peak indicates the envelope signal having the intensity of V _1. The existence probability is shown. For simplicity, it is assumed that the relationship V ₂ = 2V ₁ is established.

As shown in FIG. 7, the signals S ₁ (t) and S ₂ (t) input to the amplifier have an intensity of V ₂ with a probability of 90% or more. That is, the probability that a peak appears is small, and the instantaneous power is small at most times. At this time, the input power to the amplifier can be reduced, so that the power loss at the termination resistor can be reduced. Specifically, when the efficiency of the amplifier is 100%, the power efficiency is 32%. In the conventional LINC method, since the power efficiency is 10%, it can be said that the power efficiency is greatly improved in this embodiment.

Note that the process of limiting the amplitude of V (t) with V _max (steps S2 and S3) may be omitted.

In this embodiment, the intensity of the signals S ₁ (t) and S ₂ (t) is binary, but the intensity that the signals S ₁ (t) and S ₂ (t) can take is Three or more values may be used. If the strengths that the signals S ₁ (t) and S ₂ (t) can take are increased, the power efficiency can be further improved. In the following, a brief description will be given of the case where the envelope signals S ₁ (t) and S ₂ (t) can have three values.

First, V ₁ , V ₂ , and V ₃ exist as intensities that the signals S ₁ (t) and S ₂ (t) can take. Here, it is assumed that a relationship of V ₁ > V ₂ > V ₂ is established among V ₁ , V ₂ , and V ₂ . Further, for the sake of simplicity, it is assumed that the relationship of V ₁ = 2V ₂ and V ₂ = 2V ₃ is established. In this case, the signal processing unit 104, when V (t) ≧ 2V ₂ sets the amplitude data to V _1, when _{2V 1 ≦ V (t) <} 2V 2 sets the amplitude data to V _2, when V (t) of <2V ₁ sets the amplitude data to the V _2.

Incidentally, as output data, 2V was the smallest V _n satisfying _n ≧ V (t), may be not smallest satisfies even 2V _n ≧ V (t). Furthermore, the amplitude of V _n may be a multiple of the above real number. That is, aV _n (a is a real number) may be used as output amplitude data.

  Here, in the present embodiment, the intensity of the envelope signal input to the amplifier varies between discrete values as time passes, and thus is not always a constant value. Therefore, if the amplifier has nonlinearity, the amplified signal may be distorted. In order to solve such a problem, it is only necessary to compensate for the nonlinearity of the amplifier by previously distorting the baseband signal to the inverse characteristic of the nonlinear characteristic of the amplifier. In the example described here, since the envelope is binary, the transmitter may acquire the gain and pass phase data at the time of output, and give the reverse characteristics to the baseband signal. Note that baseband distortion compensation data may be stored in a memory as a table. As a result, the memory capacity can be reduced as compared with the conventional distortion compensation.

(Second Embodiment)
Below, the 2nd Embodiment of this invention is described, referring drawings. In the transmitter to which the data conversion apparatus according to this embodiment is applied, the signal input to the amplifier is different from that of the first embodiment. Here, FIG. 8 is a block diagram showing a configuration of the transmitter.

  The transmitter shown in FIG. 8 includes an input terminal 801, an output terminal 802, an amplitude limiter 803, a signal processor 804, an angle modulator 805, an angle modulator 806, an amplitude modulator 807, an amplitude modulator 808, a combiner 809, and And a terminating resistor 810.

  Note that the input terminal 801, the output terminal 802, the amplitude limiting unit 803, the combining unit 809, and the termination resistor 810 are the same as those in the first embodiment, and thus description thereof is omitted.

Here, the signal processing unit 804 according to the present embodiment is different from the first embodiment in the way of outputting signals. Specifically, the signal processing unit 104 according to the first embodiment outputs the amplitude data V _n and the phase data θ (t) + φ (t) to the vector modulator 105, and the amplitude data V _n and the phase data θ. (T) −φ (t) was output to the vector modulator 106. In contrast, the signal processing unit 804 according to the present embodiment outputs the amplitude data V _n to the amplitude modulators 807 and 808, and the phase modulator θ (t) + φ (t) with respect to the angle modulator 805. The phase data θ (t) −φ (t) is output to the angle modulator 806. Note that the generation method of the amplitude data V _n and the phase data θ (t) + φ (t) and θ (t) −φ (t) is the same as that in the first embodiment, and thus the description thereof is omitted.

  The angle modulator 805 angle-modulates the output phase data θ (t) + φ (t), and generates two angle-modulated wave signals having constant amplitude and continuously changing phase. The angle modulator 806 angle-modulates the output phase data θ (t) −φ (t), and generates two angle-modulated wave signals having constant amplitude and continuously changing phase. The angle modulated wave signal obtained by modulating the phase data θ (t) + φ (t) is output to the amplitude modulator 807, and the angle obtained by modulating the phase data θ (t) −φ (t). The modulated wave signal is output to amplitude modulator 808.

The amplitude modulators 807 and 808 are realized by, for example, a circuit including a MOS transistor, and amplitude-modulate the acquired angle-modulated wave signal with the amplitude data V _n . Here, the configuration of the amplitude modulators 807 and 808 will be described with reference to the drawings. FIG. 9 is a diagram showing the configuration of the amplitude modulators 807 and 808. FIG. 10 is a diagram showing waveforms of signals input to and output from each terminal.

  The amplitude modulators 807 and 808 include an input terminal 901, an output terminal 902, a MOS transistor 903, a matching circuit 904, a matching circuit 905, a bias circuit 906, a bias circuit 907, a gate voltage supply terminal 908, and a drain voltage supply terminal 909. .

The input terminal 901 is connected to the angle modulator 805 or 806, and receives an angle modulated wave signal shown in FIG. A DC voltage is applied to the gate voltage supply terminal 908 so as to obtain a desired gain in the MOS transistor 903. The drain voltage supply terminal 909 is connected to the signal processing unit 804 and receives the amplitude data V _n shown in FIG. The MOS transistor 903 amplifies the angle-modulated wave signal, and further amplitude-modulates the amplified angle-modulated wave signal with the amplitude data V _n . A signal shown in FIG. 10C is output from the output terminal 902. The matching circuits 904 and 905 and the bias circuits 906 and 907 are also provided in a general amplitude modulator, and detailed description thereof is omitted.

  The operation of the transmitter configured as described above and to which the data conversion apparatus according to this embodiment is applied will be described below.

Since the amplitude data V (t) and the phase data θ (t) are input to the input terminal 801, the signal processing unit 804 receives the amplitude data V _n , phase data θ (t) + φ (t), and phase data. The process up to the point where θ (t) −φ (t) is generated is the same as that in the first embodiment, and a description thereof will be omitted.

The signal processing unit 804 that has generated the amplitude data V _n , the phase data θ (t) + φ (t) and the phase data θ (t) −φ (t) outputs the amplitude data V _n to the amplitude modulators 807 and 808. The phase data θ (t) + φ (t) is output to the angle modulator 805, and the phase data θ (t) −φ (t) is output to the angle modulator 806.

  Next, the angle modulator 805 angle-modulates the acquired phase data θ (t) + φ (t), and the intensity of the envelope as shown in FIG. 10A is constant over time. Generate a signal. Similarly, the angle modulator 806 performs angle modulation on the acquired phase data θ (t) −φ (t), and the intensity of the envelope as shown in FIG. 10A is constant over time. Generate a signal. Then, the angle modulator 805 outputs a signal obtained by modulating the phase data θ (t) + φ (t) to the amplitude modulator 807. Further, the angle modulator 806 outputs a signal obtained by modulating the phase data θ (t) −φ (t) to the amplitude modulator 808.

As described above, the amplitude modulator 807 performs amplitude modulation using the signal obtained by modulating the phase data θ (t) + φ (t) and the amplitude data V _n, and FIG. An envelope signal having a waveform as shown in FIG. Similarly, the amplitude modulator 808 performs amplitude modulation using the signal obtained by modulating the phase data θ (t) −φ (t) and the amplitude data V _n , and the waveform shown in FIG. A signal having a waveform as shown is output to the combiner 809. Thereafter, the processing performed by the synthesizer 809 is the same as that in the first embodiment, and thus the description thereof is omitted.

  As described above, according to the transmitter to which the data conversion apparatus according to the present embodiment is applied, as shown in FIG. 9, amplitude data having discrete strength is applied to the drain of the transistor. Signal amplification and amplitude modulation are performed. Even when the transistor operates at a saturated output, the linearity of the output with respect to the drain voltage is easy to ensure. As a result, in this embodiment, the distortion of the output signal due to transistor nonlinearity is less likely to occur than in the first embodiment.

Further, according to the transmitter to which the data conversion apparatus according to the present embodiment is applied, the amplitude V _{n of} S ₁ (t) and S ₂ (t) is input as in the first embodiment. Depending on the magnitude of the incoming amplitude data V (t), it changes to a multi-stage value. Therefore, when the magnitude of the input amplitude data V (t) becomes small, V (t) can be expressed using a small amplitude V _n, and the base of S ₁ (t) The angle formed between the band signal and the baseband signal of S ₂ (t) can be reduced. As a result, the components that cancel each other out between S ₁ (t) and S ₂ (t) can be reduced, and the power efficiency can be improved.

In the present embodiment, a DC voltage is applied to the gate voltage supply terminal 908, and the amplitude data V _n is input to the drain voltage supply terminal 909. The amplitude data V _n may be input to the voltage supply terminal 908 and a DC voltage may be applied to the drain voltage supply terminal 909.

  The amplitude modulators 807 and 808 are realized by a circuit including a MOS transistor, but may be a MES-FET or a bipolar transistor.

(Third embodiment)
Hereinafter, a transmitter to which a data conversion apparatus according to a third embodiment of the present invention is applied will be described with reference to the drawings. The transmitter is different from the transmitter in the second embodiment in the configuration of the amplitude modulator. Here, FIG. 11 is a block diagram showing a configuration of the transmitter. Note that the same reference numerals are assigned to the same parts as those of the transmitter of the second embodiment.

  11 includes an input terminal 801, an output terminal 802, an amplitude limiting unit 803, a signal processing unit 804, an angle modulator 805, an angle modulator 806, a combiner 809, a termination resistor 810, a switch control unit 1000, an amplitude, A modulator 1001 and an amplitude modulator 1002 are provided.

  Since the input terminal 801, the output terminal 802, the amplitude control unit 803, the angle modulator 805, the angle modulator 806, the combiner 809, and the termination resistor 810 are the same as those described in the second embodiment, Description is omitted.

Amplitude modulators 1001 and 1002 amplitude-modulate the angle-modulated wave signals output from angle modulators 805 and 806 with amplitude data V _n . Here, the amplitude modulators 1001 and 1002 have the structure shown in FIG.

  The amplitude modulators 1001 and 1002 include an input terminal 1005, a switch 1006, a switch 1007, an amplifier 1008, an amplifier 1009, a switch 1010, a switch 1011 and an output terminal 1012.

Switches 1006, 1007, 1010, and 1011 are switches for turning on / off the operations of the amplifiers 1008 and 1009, and operate based on the control of the switch control unit 1000. The amplifier 1008 is an amplifier having a relatively large gain. When the amplitude data V _n is V ₁ , the amplifier 1008 operates when the switches 1006 and 1010 are turned on, and the amplitude of the input angle-modulated wave signal is changed. Amplify. The amplifier 1009 is an amplifier having a relatively small gain, and operates when the switches 1007 and 1011 are turned on when the amplitude data V _n is V ₂ . Amplify the amplitude. In this embodiment, since 2V ₂ = V ₁ , the output power of the amplifier 1008 is 6 dB larger than the output power of the amplifier 1009.

The switch control unit 1000 controls ON / OFF of the switches 1006, 1007, 1010, and 1011 based on the amplitude data V _n output from the signal processing unit 804. Specifically, when the amplitude data V _n is V ₁ , the switch control unit 1000 turns on the switches 1006 and 1010. When the amplitude data V _n is V ₂ , the switch controller 1000 turns on the switches 1007 and 1011.

  The operation of the transmitter to which the data conversion apparatus according to this embodiment configured as described above is applied will be described below.

Since the amplitude data V (t) and the phase data θ (t) are input to the input terminal 801, the signal processing unit 804 receives the amplitude data V _n , phase data θ (t) + φ (t), and phase data. The process until θ (t) −φ (t) is generated is the same as in the first and second embodiments, and thus the description thereof is omitted.

The signal processing unit 804 that has generated the amplitude data V _n , the phase data θ (t) + φ (t) and the phase data θ (t) −φ (t) outputs the amplitude data V _n to the switch control unit 1000, and the phase data Data θ (t) + φ (t) is output to angle modulator 805, and phase data θ (t) −φ (t) is output to angle modulator 806.

  Next, the angle modulator 805 angle-modulates the acquired phase data θ (t) + φ (t), and the intensity of the envelope as shown in FIG. 10A is constant over time. Generate an envelope signal. Similarly, the angle modulator 806 performs angle modulation on the acquired phase data θ (t) −φ (t), and the intensity of the envelope as shown in FIG. 10A is constant over time. Generate an envelope signal. Then, the angle modulator 805 outputs a signal obtained by modulating the phase data θ (t) + φ (t) to the amplitude modulator 1001. Further, the angle modulator 806 outputs a signal obtained by modulating the phase data θ (t) −φ (t) to the amplitude modulator 1002.

As described above, the amplitude modulator 1001 modulates and amplifies the signal obtained by modulating the phase data θ (t) + φ (t) based on the control of the switch control unit 1000, as shown in FIG. An envelope signal having a waveform as shown in c) is output to the synthesizer 809. Specifically, when the amplitude data V _n input to the switch control unit 1000 is V ₁ , the amplitude modulator 1001 relatively amplifies the output signal using the amplifier 1008 and outputs the amplified signal. When the amplitude data V _n input to the control unit 1000 is V ₂ , the acquired signal is amplified relatively small using the amplifier 1009 and output. Note that the operation of the amplitude modulator 1002 is the same as the operation of the amplitude modulator 1001, and a description thereof will be omitted. Further, the operation performed by the synthesizer 809 is the same as that in the first and second embodiments, and the description thereof is omitted.

As described above, according to the transmitter that the data conversion apparatus is applied according to the present embodiment, in accordance with the magnitude of the amplitude data V _n, it is switched amplifier used. Therefore, each amplifier included in the transmitter may always amplify the signal with a constant gain. Therefore, even if the amplifier has non-linearity, the output signal is less likely to be distorted. Furthermore, since the amplifier always operates at a constant gain, it is possible to always operate the amplifier at a saturated power. As a result, the power efficiency of the entire transmitter is improved.

Further, according to the transmitter to which the data conversion apparatus according to the present embodiment is applied, the amplitude V _{n of} S ₁ (t) and S ₂ (t) is input as in the first embodiment. Depending on the magnitude of the incoming amplitude data V (t), it changes to a multi-stage value. Therefore, when the magnitude of the input amplitude data V (t) becomes small, V (t) can be expressed using a small amplitude V _n, and the base of S ₁ (t) The angle formed between the band signal and the baseband signal of S ₂ (t) can be reduced. As a result, the components that cancel each other out between S ₁ (t) and S ₂ (t) can be reduced, and the power efficiency can be improved.

FIG. 13 is a graph showing the relationship between the intensity of the amplitude data V _n and time. The vertical axis represents an intensity of V _n of the amplitude data, the horizontal axis indicates the elapsed time. FIG. 14 is a graph showing temporal changes in the phase data θ (t) + φ (t) of S ₁ (t) when the amplitude data V _n changes as shown in FIG. The vertical axis indicates the magnitude of the phase data θ (t) + φ (t), and the horizontal axis indicates the elapsed time.

As shown in FIG. 13, the intensity of the intensity of the amplitude data V _n is the switched from V ₂ or vice V ₂ from V ₁ to V _1, as shown in FIG. 14, the phase of about 60 ° discontinuously changes. This will be described below with reference to the drawings. 15, when the intensity of the intensity of the amplitude data V _n is changed from V ₂ or vice V ₂ from V ₁ to V _1, S (t) and S ₁ (t) (or S ₂ (t)) and is It is the figure which showed the mode of the angle | corner (phi) (t) to make.

Here, as shown in FIG. 15, at the time when V (t) is 2V _2, switched amplitude data V _n from V ₁ from V ₂ or vice V ₂ to V _1. In this case, the angle φ (t) formed by S (t) and S ₁ (t) (or S ₂ (t)) changes discontinuously by 60 °. Such a discontinuous change in φ (t) causes a problem when the angle modulators 805 and 806 perform modulation using a PLL (Phase Locked Loop). This will be specifically described below.

  When performing modulation using a PLL, low-pass filters are provided in the angle modulators 805 and 806. The low-pass filter has a property of easily generating a delay with respect to a signal passing therethrough. Therefore, when the phase changes greatly and discontinuously as described above, the low-pass filter cannot follow the change in the phase. As a result, distortion occurs in the waveform of the angle-modulated signal.

  Therefore, when the angle modulators 805 and 806 perform the modulation using the PLL, the phase correction unit 1200 is provided in the transmitter to which the data conversion apparatus according to the present embodiment is applied, as shown in FIG. Is desirable. Accordingly, as shown in FIG. 17, a phase shifter 1250 is provided in the amplitude modulator 1201, and a phase shifter 1251 is provided in the amplitude modulator 1202 as shown in FIG. desirable.

Here, when the amplitude data V _n output from the signal processing unit 804 is V ₁ , the phase correction unit 1200 subtracts 60 ° from the phase data θ (t) + φ (t), and the angle modulator This is a circuit that outputs to 805, adds 60 ° to the phase data θ (t) −φ (t), and outputs the result to the angle modulator 806. As described above, when the amplitude data V _n is switched from V ₂ to V ₁ , the phase data θ (t) + φ (t) increases discontinuously by 60 °, and the phase data θ (t) − φ (t) decreases discontinuously by 60 °. In such a case, when the amplitude data V _n is V ₁ , the phase correction unit 1200 subtracts 60 ° from the phase data θ (t) + φ (t) to obtain the phase data θ (t) −φ (t). By adding 60 °, the phase data θ (t) + φ (t) and θ (t) −φ (t) can be regarded as continuously changing. Further, when the amplitude data is V _1, the phase shifter 1250 advances the phase by 60 ° (that is, adds 60 ° to the phase) to the amplifier 1008 included in the amplitude modulator 1201 to which the phase data θ (t) + φ (t) is input. When the amplitude data is V ₁ , the phase is delayed by 60 ° in the amplifier 1008 included in the amplitude modulator 1202 to which the phase data θ (t) −φ (t) is input (that is, the phase is reduced by 60 °). ) By providing the phase shifter 1251, the phase data θ (t) + φ (t) and θ (t) −φ (t) are returned to the original data. As described above, the data converter according to the present embodiment is applied by shifting the phase before the angle modulators 805 and 806 and returning the shifted phase to the original state after the angle modulators 805 and 806. It becomes possible to apply angle modulation using PLL to the transmitter.

Here, when the amplitude data V _n is V ₁ , the phase correction unit 1200 subtracts 60 ° from the phase data θ (t) + φ (t) to obtain the phase data θ (t) −φ (t). Further, the phase shifter 1250 adds 60 ° to the phase, and the phase shifter 1251 subtracts the phase by 60 °. However, the phase correction method is not limited to this. Specifically, when the amplitude data V _n is V ₂ , the phase correction unit 1200 adds 60 ° to the phase data θ (t) + φ (t) to obtain the phase data θ (t) −φ (t). 60 degrees may be subtracted from the phase shifter, and the phase shifter 1250 may further subtract the phase by 60 degrees, and the phase shifter 1251 may add the phase by 60 degrees. However, in the case of a signal having a large peak factor, the amplitude data V _n is more likely to be V ₂ . For this reason, when such a signal having a large peak factor is input, it is preferable to apply phase correction when the amplitude data V _n is V ₁ from the viewpoint of reducing the processing load on the entire transmitter.

  It is difficult for the phase shifter 1251 to subtract the phase by 60 °. Therefore, in practice, this is realized by adding (offset) the phase of 60 ° to the four amplifiers.

In addition, here, the values that the phase data V _n can take are binary values of V ₁ and V ₂ , but the values that the phase data V _n can take are not limited to this. Furthermore, the relationship of V ₁ = 2V ₂ is established between V ₁ and V ₂ , but the relationship is not limited to this. However, when the relationship of V ₁ = aV ₂ (a is a constant) is established between V ₁ and V ₂ , α (α = cos ⁻¹ (1 / a), 0 instead of 60 ° ° <α <90 °) is used.

  The data conversion apparatus according to the present invention can amplify an envelope signal having a large peak factor with high power efficiency without generating distortion, and includes first amplitude data and first phase data. It is useful as a data converter for converting an input signal into first and second output signals.

It is the block diagram which showed the whole structure of the transmitting apparatus which concerns on the 1st Embodiment of this invention. It is the figure which showed the mechanism of the conversion at the time of the signal processing part of this invention performing data conversion. It is the flowchart which showed the operation | movement which an amplitude limitation part and a signal processing part perform. It is a diagram showing a waveform of before and after the amplification envelope signal S ₁ (t) and S ₂ (t). It is the figure which showed the complex envelope (IQ signal) of the modulated wave before amplification input into two amplifiers. It is the figure which showed the complex envelope (IQ signal) of the modulated wave after amplification and a synthesis | combination. The existence probabilities at the respective intensities of the envelope signals of S ₁ (t) and S ₂ (t) are shown. It is the block diagram which showed the whole structure of the transmitting apparatus which concerns on the 2nd Embodiment of this invention. FIG. 10 is a block diagram showing a detailed configuration of an amplitude modulator included in the transmitter of FIG. 9. FIG. 10 is a diagram illustrating waveforms of signals input to and output from each terminal of the amplitude modulator in FIG. 9. It is the block diagram which showed the whole structure of the transmitting apparatus which concerns on the 3rd Embodiment of this invention. FIG. 12 is a block diagram illustrating a detailed configuration of an amplitude modulator included in the transmitter of FIG. 11. It is a graph showing the relationship between the intensity and time of the amplitude data V _n. FIG. 14 is a graph showing temporal changes in phase data θ (t) + φ (t) of S ₁ (t) when amplitude data V _n changes as shown in FIG. When the intensity of the intensity of the amplitude data V _n is changed from V ₂ or vice V ₂ from V ₁ to V _1, S (t) and S ₁ (t) (or S ₂ (t)) and the angle phi ( It is the figure which showed the mode of t). It is the block diagram which showed the whole structure of the transmitter of the other example of the 3rd Embodiment of this invention. It is the block diagram which showed the detailed structure of the amplitude modulator of the transmitter shown in FIG. It is the block diagram which showed the detailed structure of the amplitude modulator of the transmitter shown in FIG. It is the block diagram which showed the structure of the conventional transmitter. It is the figure which showed the waveform of the input signal and output signal in the conventional transmitter. It is the figure which showed the relationship of the intensity | strength and phase of the signal which are each input into two amplifiers, when two cases, when the instantaneous electric power input is large and when it is small. It is the figure which showed the complex envelope (IQ signal) of the modulated wave before amplification input into two amplifiers. It is the figure which showed distribution of the intensity | strength of the envelope of a modulated wave.

Explanation of symbols

103, 803 Amplitude control section 104, 804 Signal processing section 105, 106 Vector modulator 107, 108 Amplifier 109, 809 Synthesizer 110, 810 Termination resistor 805, 806 Angle modulator 807, 808, 1001, 1002, 1201, 1202 Amplitude Modulator 903 MOS transistor 904, 905 Matching circuit 906, 907 Bias circuit 1000 Switch controller 1006, 1007, 1010, 1011 Switch 1008, 1009 Amplifier 1300, 1301 Phaser

Claims (12)

An apparatus for converting an input signal including first amplitude data and first phase data into first and second output signals,
The first and second output signals each include second amplitude data having the same magnitude,
Determination means for determining whether or not the first amplitude data is greater than a predetermined value;
When the determination means determines that the first amplitude data is greater than the predetermined value, second amplitude data having a first data value is generated, and the first amplitude data is the predetermined value. Amplitude data generating means for generating second amplitude data having a second data value smaller than the first data value when the determining means determines that:
When the first amplitude data is larger than the predetermined value, the input signal is decomposed into first and second output signals including second amplitude data having the first data value. Generating second phase data included in the first output signal and third phase data included in the second output signal, and when the first amplitude data is equal to or less than the predetermined value, When the determination means determines, the input signal is decomposed into first and second output signals including second amplitude data having the second data value, and the second phase data and the second phase data A data conversion device comprising phase data generation means for generating third phase data.   The data conversion apparatus according to claim 1, wherein the second data value is ½ of the first data value. Threshold determination means for determining whether or not the first amplitude data of the input signal is larger than a preset threshold;
An amplitude limiting unit configured to set the first amplitude data as the threshold value and output to the determination unit when the threshold value determining unit determines that the first amplitude data is greater than the threshold value; The data conversion device according to claim 1, further comprising:   The phase difference between the first phase data and the second phase data and the phase difference between the first phase data and the third phase data are based on the first amplitude data and the second phase data 2. The data conversion device according to claim 1, wherein the angle is equal to an angle between a base and a hypotenuse of a right triangle having a hypotenuse twice as long as the amplitude data. A transmitter that modulates, amplifies and transmits an input signal including first amplitude data and first phase data,
Conversion means for converting the input signal into first and second output signals each including second amplitude data having the same magnitude;
The converting means includes
Determination means for determining whether or not the first amplitude data is greater than a predetermined value;
When the determination means determines that the first amplitude data is greater than the predetermined value, second amplitude data having a first data value is generated, and the first amplitude data is the predetermined value. Amplitude data generating means for generating second amplitude data having a second data value smaller than the first data value when the determining means determines that the value is smaller than the first data value;
When the first amplitude data is larger than the predetermined value, the input signal is decomposed into first and second output signals including second amplitude data having the first data value. The second phase data included in the first output signal and the third phase data included in the second output signal are generated, and the determination is made that the first amplitude data is smaller than the predetermined value. If the means determines, the input signal is decomposed into first and second output signals including second amplitude data having the second data value, and the second phase data and third Phase data generating means for generating the phase data of
Based on the second amplitude data generated by the amplitude data generation means and the second phase data generated by the phase data generation means, a first output signal that is amplitude-modulated and angle-modulated is generated, Modulation means for generating a second output signal that is amplitude-modulated and angle-modulated based on the second amplitude data generated by the amplitude data generation means and the third phase data generated by the phase data generation means; ,
First amplifying means for amplifying the amplitude of the first output signal generated by the modulating means;
Second amplification means for amplifying the amplitude of the second output signal generated by the modulation means;
The transmitter further comprising a combining unit that combines the first output signal amplified by the first amplifying unit and the second output signal amplified by the second amplifying unit.   The second amplitude data and the second phase data are corrected so as to correct the nonlinearity of the first amplifying means, and the second amplitude data is corrected so as to correct the nonlinearity of the second amplifying means. The transmitter according to claim 5, further comprising data correction means for correcting the amplitude data and the third phase data. A transmitter for amplifying and transmitting first amplitude data of an input signal including first amplitude data and first phase data,
Conversion means for converting the input signal into first and second output signals each including second amplitude data having the same magnitude;
The converting means includes
Determination means for determining whether or not the first amplitude data is greater than a predetermined value;
When the determination means determines that the first amplitude data is greater than the predetermined value, second amplitude data having a first data value is generated, and the first amplitude data is the predetermined value. Amplitude data generating means for generating second amplitude data having a second data value smaller than the first data value when the determining means determines that the value is smaller than the first data value;
When the first amplitude data is larger than the predetermined value, the input signal is decomposed into first and second output signals including second amplitude data having the first data value. The second phase data included in the first output signal and the third phase data included in the second output signal are generated, and the determination is made that the first amplitude data is smaller than the predetermined value. If the means determines, the input signal is decomposed into first and second output signals including second amplitude data having the second data value, and the second phase data and the second Phase data generation means for generating phase data of 3;
Based on the second phase data generated by the phase data generating means, an angle-modulated first angle-modulated wave signal is generated, and based on the third phase data generated by the phase data generating means, the angle Angle modulated wave signal generating means for generating a modulated second angle modulated wave signal;
First amplitude modulation means for modulating the first angle modulation wave signal generated by the angle modulation wave signal generation means using the second amplitude data and generating a first output signal;
Second amplitude modulation means for modulating the second angle modulation wave signal generated by the angle modulation wave signal generation means using the second amplitude data and generating a second output signal;
A transmitter comprising: a combining unit configured to combine the first output signal generated by the first amplitude modulation unit and the second output signal generated by the second amplitude modulation unit. The first amplitude modulation means and the second amplitude modulation means are constituted by an amplifier including a transistor,
The first angle modulation wave signal is input to the control electrode of the first amplitude modulation means, and the conduction electrode of the first amplitude modulation means corresponds to the data value of the second amplitude data. Voltage is applied,
The second angle modulation wave signal is input to the control electrode of the second amplitude modulation means, and the conduction electrode of the second amplitude modulation means corresponds to the data value of the second amplitude data. Transmitter according to claim 7, characterized in that a voltage is applied. The first amplitude modulation means and the second amplitude modulation means are constituted by an amplifier including a transistor,
A voltage corresponding to a data value of the first angle modulation wave signal and the second amplitude data is applied to the control electrode of the first amplitude modulation means,
The voltage according to the data value of said 2nd angle modulation wave signal and said 2nd amplitude data is applied to the control electrode of said 2nd amplitude modulation means, It is characterized by the above-mentioned. Transmitter. The first amplitude modulation means includes a first amplifier and a second amplifier having a gain smaller than that of the first amplifier;
The second amplitude modulation means includes a third amplifier and a fourth amplifier having a gain smaller than that of the third amplifier,
When the second amplitude data is a first data value, a first amplifier amplifies the first angle modulated wave signal and a third amplifier receives the second angle modulated wave signal. If the second amplitude data is a second data value, the second amplifier amplifies the first angle modulated wave signal and the third amplifier amplifies the fourth The transmitter according to claim 6, further comprising switch control means for amplifying the amplitude of the angle-modulated wave signal. The second phase data is larger than the first phase data by a predetermined phase,
The third phase data is smaller than the first phase data by a predetermined phase,
When the second amplitude data is a first data value, a predetermined phase having a magnitude of 0 to 90 ° is subtracted from the second phase data, and 0 is added to the third phase data. First phase correction means for adding a predetermined phase having a magnitude of ˜90 °;
When the second amplitude data is a first data value, the predetermined phase having the magnitude of 0 to 90 ° is added to the phase of the first angle-modulated wave signal, and the second The transmitter according to claim 7, further comprising: a second phase correcting unit that subtracts the predetermined phase having the magnitude of 0 to 90 ° from the phase of the angle modulated wave signal.   The transmission according to claim 11, wherein the predetermined phase is an angle between a hypotenuse and a base of a right triangle having the first data value as a hypotenuse and the second data value as a base. Machine.

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