Electronic device and signal processing method

Abstract

To estimate a distortion characteristic of at least one of a transmission system and a loop-back system.SOLUTION: An electronic apparatus according to the present embodiment includes: a signal generation unit that generates a first signal and a second signal; a first characteristic unit that applies a first distortion characteristic to the first signal to obtain a first distortion signal, and applies the first distortion characteristic to the second signal to obtain a second distortion signal; a time characteristic unit that applies, to the first distortion signal, a first time characteristic, which is a distortion characteristic that changes according to time to obtain a third distortion signal, and applies, to the second distortion signal, a second time characteristic, which is the distortion characteristic that changes according to time to obtain a fourth distortion signal; a second characteristic unit that applies a second distortion characteristic to the third distortion signal to obtain a fifth distortion signal, and applies the second distortion characteristic to the fourth distortion signal to obtain a sixth distortion signal; and a distortion estimation unit that estimates at least one of the first distortion characteristic and the second distortion characteristic on the basis of the first signal, the second signal, the fifth distortion signal, and the sixth distortion signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to electronic devices and signal processing methods. [Background technology]

[0002] In a transmitter that performs wireless communication, a portion of the signal transmitted from the transmission system is looped back as a loopback (LB) signal for the purpose of compensating for distortion in the transmitted signal. The looped-back signal (LB signal) is acquired through a receiving system circuit dedicated to LB signals. Therefore, the acquired LB signal contains the frequency characteristics of the LB system circuit (distortion characteristics of the LB system) in addition to the frequency characteristics of the transmission system circuit (distortion characteristics of the transmission system).

[0003] Wider and more stable communications are required in cellular networks and television broadcasting. In wideband communication systems, distortion caused by the frequency characteristics of the transmission system cannot be ignored in the transmitter that performs wireless communication. However, even if the LB signal is used to estimate and compensate for this distortion, the product of the distortion characteristics of the transmission system and the LB system can be estimated, but each distortion characteristic cannot be estimated individually.

[0004] Furthermore, broadband communication systems generally use power amplifiers (PAs), which distort signals over time. Therefore, to perform stable distortion compensation, it is necessary to loop back the output from the PA (PA output) and monitor the distortion compensation status while performing distortion compensation. To monitor the distortion compensation status, it is necessary to estimate accurate PA output. To estimate accurate PA output, it is also necessary to estimate the distortion characteristics of the transmission system and the LB system separately. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Y. Ma, et al., “Test Bed for Characterization and Predistortion of Power Amplifiers”, International Journal of RF and Microwave Computer-Aided Engineering 23(1):74-82 Summary of the Invention [Problem to be solved by the invention]

[0006] Embodiments of the present invention provide an electronic device and a signal processing method that enable estimation of distortion characteristics of at least one of a transmission system and a loopback system. [Means for solving the problem]

[0007] The electronic device of this embodiment includes a signal generation unit that generates a first signal and a second signal; a first characteristic unit that imparts a first distortion characteristic to the first signal to obtain a first distorted signal and imparts the first distortion characteristic to the second signal to obtain a second distorted signal; a time characteristic unit that imparts a first time characteristic, which is a distortion characteristic that changes over time, to the first distorted signal to obtain a third distorted signal and imparts a second time characteristic, which is a distortion characteristic that changes over time and is different from the first time characteristic, to the second distorted signal to obtain a fourth distorted signal; a second characteristic unit that imparts a second distortion characteristic to the third distorted signal to obtain a fifth distorted signal and imparts the second distortion characteristic to the fourth distorted signal to obtain a sixth distorted signal; and a distortion estimation unit that estimates at least one of the first distortion characteristic and the second distortion characteristic based on the first signal, the second signal, the fifth distorted signal, and the sixth distorted signal. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram of a signal processing device according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing another representation of the signal processing device according to the first embodiment. [Figure 3]FIG. 4 is a block diagram showing a modified example of the signal processing device according to the first embodiment. [Figure 4] FIG. 10 is a block diagram showing another modified example of the signal processing device according to the first embodiment. [Figure 5] 4 is a flowchart illustrating processing performed by the signal processing device according to the first embodiment. [Figure 6] FIG. 10 is a block diagram of a signal processing device according to a second embodiment. [Figure 7] FIG. 10 is a block diagram of a signal processing device according to a third embodiment. [Figure 8] FIG. 11 is a block diagram showing a modified example of the signal processing device according to the third embodiment. [Figure 9] 10 is a flowchart illustrating processing performed by a signal processing device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] (First embodiment) 1 is a block diagram showing a signal processing device 1 as an electronic device according to a first embodiment. The signal processing device 1 is an electronic device including a signal generation unit 2, a transmission signal processing unit 3, a time characteristic unit 4, an LB signal processing unit 5, a distortion estimation unit 6, a distortion compensation unit 7, and an output unit 8. In the first embodiment, the frequency characteristic (distortion characteristic of the transmission system) specific to the transmission signal processing unit 3 is estimated regardless of the signal band.

[0011] In this embodiment, a factor that distorts a signal on the frequency axis and / or the time axis is referred to as a "characteristic" or "distortion characteristic." Also, in this embodiment, an element that distorts a signal (causes distortion in a signal) by imparting some characteristic to the signal and outputs the distorted signal is referred to as a "characteristic unit." "Giving a characteristic to a signal" can be modeled, for example, by multiplying the signal by a matrix or value defined according to the characteristic. In this embodiment, the transmission signal processing unit 3, the time characteristic unit 4, and the LB signal processing unit 5 all correspond to characteristic units.

[0012] 2 is a block diagram of the signal processing device 1 when the transmission signal processing unit 3, the time characteristic unit 4, and the LB signal processing unit 5 are viewed as characteristic units. The first characteristic unit 3 corresponds to the transmission signal processing unit 3, the second characteristic unit 5 corresponds to the LB signal processing unit 5, and the time characteristic unit 4 corresponds to the separation characteristic unit 4. That is, in the first embodiment, the first characteristic unit 3 corresponds to the transmission signal processing unit 3 that performs various processes using elements 31 to 33 to transmit a signal, and the second characteristic unit 5 corresponds to the LB signal processing unit 5 that performs various processes using elements 51 to 53 to acquire an LB signal. The separation characteristic unit 4 corresponds to the time characteristic unit 4 that performs processing to impart a time-varying distortion characteristic that is a feature of this embodiment, thereby enabling the distortion characteristics of the transmission system and the distortion characteristics of the loopback system to be separately estimated.

[0013] At least some of the signal generating unit 2, transmission signal processing unit (first characteristic unit) 3, time characteristic unit (separation characteristic unit) 4, LB signal processing unit (second characteristic unit) 5, distortion estimating unit 6, distortion compensating unit 7, and output unit 8 may be configured by a circuit or processor such as an ASIC (application specific integrated circuit) or FPGA (field-programmable gate array). Alternatively, some or all of these elements may be executed by a CPU that executes a program.

[0014] The signal generating unit 2 generates a signal including a signal (digital signal) X1 and a signal (digital signal) X2. The signal X1 and the signal X2 are signals at different times. The signal generating unit 2 may switch between the output of the signal X1 and the signal X2 over time. The signal generating unit 2 may also divide one signal into the signal X1 and the signal X2. Hereinafter, when there is no need to distinguish between the signal X1 and the signal X2, the signal X1 and the signal X2 may be simply referred to as the signal X. The signal X1 and the signal X2 are examples of a first signal and a second signal, respectively, according to this embodiment.

[0015] Signal X is represented by an N × M matrix as shown in Equation 1. N is the number in the time direction, and M is the number in the system direction. One element in matrix X represents one signal. Signal X has a certain bandwidth, and one column of matrix X represents the time variation of signals having that bandwidth. That is, one column of matrix X contains N signals that vary over time. Signal X contains multiple (M) sets of N signals that vary in the time direction in the system direction. Increasing the number of columns in signal X improves the SNR in the processing performed by distortion estimation unit 6, which will be described later. Signals X1 and X2 may be signals represented by different matrices X1 and X2, or may be signals represented by the same matrix X. Matrices X1 and X2, which are different from each other, must have the same number of rows, but may have different numbers of columns (number of signals).

[0016]

number

[0017] As shown in Fig. 1, the transmission signal processing unit 3 includes a D / A converter 31, a modulator 32, and a mixer 33. The D / A converter 31 converts the signal X from a digital signal to an analog signal. The modulator 32 modulates the signal X. The mixer 33 frequency-converts (up-converts) the signal X from the baseband (BB) band to the RF (Radio Frequency) band using a local oscillation signal generated by a local oscillator (not shown). The mixer 33 frequency-converts the signal X to, for example, the Ku band.

[0018] When the transmission signal processing unit 3 performs the above processing on the signal X, the transmission system frequency characteristics due to the elements 31 to 33 included in the transmission signal processing unit 3 distort the signal X. In other words, when the transmission signal processing unit 3 is regarded as a characteristics unit, the transmission signal processing unit 3 applies the transmission system frequency characteristics (first characteristics or first distortion characteristics) H t and the signal H t It functions as the first characteristic unit 3 (see FIG. 2) that outputs X.

[0019] First characteristic H tis expressed as an N×N matrix. The first characteristic H t is an affine transformation of a signal on the frequency axis. t causes linear distortion in the signal on the frequency axis. For example, the first characteristic H t The first characteristic H may include a DC offset, which is a noise of a direct current component. t may be the IQ imbalance of the modulator 32.

[0020] A part of the signal output from the transmission signal processing unit 3 is fed back (looped back) and input to the time characteristic unit 4.

[0021] The remaining part of the signal output from the transmission signal processing unit 3 is input to the output unit 8. The output unit 8 outputs (transmits) the signal processed by the transmission signal processing unit 3. The output unit 8 is, for example, an antenna or a circuit including an antenna.

[0022] 1, the time characteristic unit 4 (separation characteristic unit 4) includes a frequency converter 41 such as a mixer and a separation characteristic switching unit 42. The frequency converter 41 generates a characteristic D. The characteristic D is intended to enable the distortion characteristics of the transmission system and the distortion characteristics of the loopback system to be acquired separately, and in view of this purpose, the characteristic D will hereinafter be referred to as the "separation characteristic D."

[0023] The separation characteristic switching unit 42 switches the separation characteristic D generated by the frequency converter 41 to the separation characteristic D p and separation characteristic D q The separation characteristic switching unit 42 switches between the separation characteristics D p and separation characteristic D q Switch between the following. p and separation characteristic D q If there is no need to distinguish between p and separation characteristic D q is sometimes simply referred to as the separation characteristic D. The separation characteristic is a distortion characteristic that changes over time, and is also referred to as a time characteristic. In this case, for example, the separation characteristic D p is the first time characteristic, and separation characteristic D qcorresponds to the second time characteristic.

[0024] The time characteristic section 4 (separation characteristic section 4) detects the signal H output from the first characteristic section 3. t X1 (first distortion signal) and signal H t X2 (second distortion signal) p and separation characteristic D q Multiplying by this gives signal D p H t X1 and signal D q H t This is the characteristic part that outputs X2.

[0025] Separation characteristic D p and separation characteristic D q are examples of the first separation characteristic (first time characteristic) and the second separation characteristic (second time characteristic) according to this embodiment. p H t X1 and signal D q H t X2 are examples of the third distorted signal and the fourth distorted signal according to this embodiment, respectively.

[0026] The separation characteristic D is expressed as an N×N diagonal matrix and varies with time. That is, D=diag[d1,d2,d3,...,d N ] and D p and D q Each element of d {p,n} , d {q,n} Then, D p and D q The element-wise quotient of d {q,n} / d {p,n} (See below for D q-p ) are different from each other. The number of elements that are different (unique) from other elements corresponds to the resolution of the desired frequency characteristics (first characteristic and / or second characteristic). Also, the separation characteristic D does not depend on the input signal. p and separation characteristic D q It is desirable that the relations be orthogonal.

[0027] Separation characteristic D generated by frequency converter 41 pand separation characteristic D q An example of this is shown in Equations 2 and 3.

[0028]

number

number

[0029] f s is the sampling frequency of the DAC 31 and the ADC 51. Here, the sampling frequencies of the DAC 31 and the ADC 51 are the same, but they do not necessarily have to match. The frequency converter 41 changes the amount of frequency shift applied to the signal X over time, for example, 2Δf, 4Δf, 6Δf, . . . The separation characteristic switching unit 42 switches the unit Δf of the amount of frequency shift of the frequency converter 41 between Δf1 and Δf2 (Δf1 ≠ Δf2), thereby changing the separation characteristic D p and separation characteristic D q Generate.

[0030] Also, as will be described later, D p -1 D q D q-p and the separation characteristic D q-p Separation characteristic D q-p is expressed as in Equation 4.

[0031]

number

[0032] 1, the LB signal processing unit 5 includes, for example, an A / D converter 51, a demodulator 52, and a mixer 53. The mixer 53 uses a local oscillation signal generated by a local oscillator to generate a signal DH t The demodulator 52 down-converts the frequency of the signal DH from the RF band to the BB band. t The A / D converter 51 demodulates the demodulated signal DH tConvert X from an analog signal to a digital signal.

[0033] The LB signal processor 5 outputs the signal DH t When the above processing is performed on X, the LB system frequency characteristics due to the elements 51 to 53 included in the LB signal processing unit 5 are t In other words, when the LB signal processing unit 5 is regarded as a characteristic unit, the LB signal processing unit 5 distorts the signal DH t X is LB frequency response (2nd characteristic or 2nd distortion characteristic) H r and the signal H r DH t It functions as the second characteristic unit 5 (see FIG. 2) that outputs X.

[0034] Second characteristic H r is expressed as an N × N matrix. The second characteristic H r is an affine transformation of the signal on the frequency axis. r causes linear distortion in the signal on the frequency axis. For example, the second characteristic H r The second characteristic H may include a DC offset, which is a noise component of a direct current. r may be the IQ imbalance of the demodulator 52.

[0035] The transmission signal processing unit 3 and / or the LB signal processing unit 5 may include a filter (not shown) that attenuates signals of any frequency component or other additional elements. The filter is arranged for the purpose of, for example, removing noise and reducing the processing load of the distortion estimation unit 6. The filter is, for example, an LTI (Linear Time-Invariant) filter such as a low-pass filter, band-pass filter, high-pass filter, all-pass filter, or anti-aliasing filter.

[0036] The distortion estimation unit 6 receives the signal Z1 (=H r D p H t X1) and signal Z2 (=H r D q H tX2) to obtain the signal Z1 (=H r D p H t X1) is the fifth distortion signal, signal Z2 (=H r D q H t X2) corresponds to the sixth distortion signal.

[0037] The distortion estimation unit 6 calculates the second characteristic H by a first calculation based on the signals X1, X2, Z1, and Z2. r By canceling out the first characteristic H t The distortion estimation unit 6 estimates the first characteristic H by a second calculation based on the signals X1, X2, Z1, and Z2. t By canceling out the second characteristic H r (Second distortion characteristic). The distortion estimation unit 6 performs the following calculation using, for example, the least squares method. Hereinafter, when there is no need to distinguish between the signals Z1 and Z2, the signals Z1 and Z2 may be simply referred to as the signals Z.

[0038] The distortion estimation unit 6 derives, for example, the following from the signal Z1 and the signal Z2: Calculate TIFF0007808008000005.tif12170 and obtain the formula shown in Equation 5.

[0039]

number

[0040] Referring to Equation 5, the second characteristic H r has been cancelled. D q-p is a diagonal matrix, so for example, H t -1 D q-p H t If we set =A, the first characteristic H t is estimated as an eigenvector of A. In this case, the separation characteristic D does not need to be known.

[0041] The distortion estimation unit 6 also derives the first characteristic H from the signal Z1 and the signal Z2. t By canceling out the second characteristic H rThe distortion estimation unit 6 may estimate, for example, Calculate TIFF0007808008000007.tif10170 and obtain the formula shown in Equation 6.

[0042]

number

[0043] Referring to Equation 6, the first characteristic H t has been cancelled. D q-p is a diagonal matrix, so for example, H r D q-p H r -1 If we set =B, the second characteristic H r is estimated as an eigenvector of B. In this case, the separation characteristic D does not need to be known. Note that the formulas for deriving each characteristic are not limited to the above formulas 4 and 5.

[0044] In the processing performed by the distortion estimation unit 6, if the LB signal processing unit 5 includes a filter, the frequency bands of the signals X and Z will change, but the frequency bands of the signals X and Z may be different.

[0045] First characteristic H t and the second characteristic H r may change over time due to temperature changes, etc. However, even in this case, the first characteristic H t and the second characteristic H r The change in the first characteristic H per unit time is smaller than the change in the separation characteristic D per unit time. t and the second characteristic H r can be treated as time-invariant on the timescale over which the separation characteristic D varies.

[0046] First characteristic H t and the second characteristic H r may be estimated at regular time intervals (frequency) during operation of the signal processing device 1, or may be estimated once when the signal processing device 1 is shipped from the factory. t and the second characteristic Hr At least one of these may be stored in a storage device such as a memory accessible from the distortion compensation unit 7.

[0047] The distortion compensation unit 7 calculates the first characteristic H estimated by the distortion estimation unit 6. t Based on this, the distortion compensator 7 performs digital predistortion (DPD) to compensate in advance for the digital signal generated by the signal generator 2. Specifically, the distortion compensator 7 applies a first characteristic H t This allows a signal that has been distortion-compensated with high precision to be output from the output unit 8.

[0048] (Variation 1) In the above description, the separation characteristic unit 4 includes the frequency converter 41. However, as shown in FIG. 3, the mixer 53 included in the second characteristic unit 5 may be included in the time characteristic unit 4 (separation characteristic unit). When the mixer 53 is included in the time characteristic unit 4, the characteristic H given by the mixer 33 up and the separation characteristic D given by the mixer 53 down is expressed as in Equation 7 and Equation 8. up causes linear distortion of the signal on the frequency axis.

[0049]

number

number

[0050] f0 is the amount of frequency shift in the up-conversion by the mixer 33. s is the sampling frequency of the mixer 33 and the mixer 53. Δf is the adjustment amount of the frequency shift provided by the mixer 53. The separation characteristic switching unit 42 switches the adjustment amount Δf of the frequency shift amount of the mixer 53 between Δf1 and Δf2, thereby providing a separation characteristic D p and separation characteristic D qGenerate.

[0051] The separation characteristic (time characteristic) may be any characteristic that changes at least one of the phase, amplitude, frequency, and impulse response of an input signal over time.

[0052] (Variation 2) Alternatively, as shown in FIG. 4, the time characteristic section 4 (separation characteristic section) may include a device switching section 43 and multiple devices 44_1 to 44_m. Each device 44 is represented as one arbitrary device 44. Each device 44 changes at least one of the phase, amplitude, frequency, and impulse response of an input signal. All devices 44 do not need to have the same function. For example, there may be a mixture of devices 44 that change the phase of the input signal and devices 44 that change the amplitude of the input signal. The device switching section 43 temporally switches the device 44 that acts on the input signal and outputs the input signal to the selected device 44. The device switching section 43 is, for example, a multiplexer or a divider. In the configuration of FIG. 4, the input signal is output to one device 44 selected by the device switching section 43. However, the input signal may be output to all of the devices 44_1 to 44_m, and the device switching section 43 may select one of the signals output from the devices 44_1 to 44_m. In this case, the device switching unit 43 may be located between the devices 44_1 to 44_m and the LB signal processing unit 5, for example.

[0053] The time characteristic unit 4 applies separation characteristics to the input signal by temporally switching the devices 44 to be affected by the device switching unit 43. Furthermore, since the signal X is expressed as an N×M matrix, the device switching unit 43 must switch the devices 44 N times, but the same device 44 may be selected multiple times. In other words, there is no need for N devices 44.

[0054] The time characteristic unit 4 may include a device that adds time-varying noise to a local oscillation signal generated by a local oscillator used for frequency conversion. The time characteristic unit 4 may include an amplifier (variable gain amplifier) ​​that changes the amplitude of the input signal over time. The time characteristic unit 4 may also include a power amplifier that amplifies the input signal and distorts the signal over time during amplification.

[0055] When the separation characteristic provided by the time characteristic section 4 is one that changes the components other than the frequency of the input signal according to time, the separation characteristic switching section 42 divides one separation characteristic into two in terms of time to provide separation characteristics D p and separation characteristic D q It may also be possible to use the following.

[0056] 5 is a flowchart illustrating the processing performed by the signal processing device 1. The processing performed by the signal processing device 1 will be described below with reference to FIG.

[0057] First, the signal generating unit 2 generates a signal X1 (first signal) (step S11).

[0058] Next, the first characteristic unit 3 applies the first characteristic H to the signal X1. t (first distortion characteristic), and signal H t X1 (first distortion signal) is output (step S12).

[0059] Next, the time characteristic section 4 (separation characteristic section) calculates the signal H t X1, separation characteristic D p (first time characteristic), and signal D p H t X1 (third distorted signal) is output (step S13).

[0060] Next, the second characteristic unit 5 calculates the signal D p H t Applying the second characteristic Hr (third distortion characteristic) to X1, the signal H r D p H t X1 (fifth distorted signal) is output (step S14).

[0061] Next, the signal generating unit 2 generates a signal X2 (second signal), and each element performs the same processing as that performed on the signal X1 (steps S11' to S14'). At this time, the time characteristic generating unit 4 generates a separation characteristic D p The separation characteristic D q (second time characteristic). Note that any one of steps S11' to S14' may be performed in parallel with any one of steps S11 to S14.

[0062] Next, the distortion estimation unit 6 calculates the signal X1, the signal X2, and the signal Z1=H. r D p H t X1 (fifth distortion signal) and signal Z2=H r D q H t The first calculation based on X2 (the sixth distortion signal) produces the second characteristic H r By canceling out the first characteristic H t is estimated (step S15).

[0063] Next, the distortion compensation unit 7 calculates the first characteristic H estimated by the distortion estimation unit 6. t Based on this, the signal generated by the signal generating unit 2 is compensated in advance (step S16).

[0064] As described above, according to the first embodiment, it is possible to separate and estimate the first characteristics (transmission system frequency characteristics, first distortion characteristics) regardless of the signal band. By compensating the signal generated by the signal generating unit based on the estimated first characteristics, it is possible to output a signal with little or no distortion. Furthermore, according to the first embodiment, it is possible to separate and estimate the second characteristics (loopback system frequency characteristics, second distortion characteristics) regardless of the signal band. Furthermore, according to the first embodiment, it is possible to separate and estimate both the first and second characteristics regardless of the signal band.

[0065] (Second embodiment) 6 is a block diagram of a signal processing device 1A as an electronic device according to this embodiment. Elements with the same names or functions as those in FIG. 1 of the first embodiment described above are assigned the same reference numerals. Hereinafter, explanations will be omitted except for changes or additions.

[0066] The signal processing device 1A includes n (n≧3) characteristic units 20_1 to 20_n. For ease of explanation, the side closer to the signal generating unit 2 along the signal path will be referred to as "front" and the side closer to the distortion estimating unit 6 will be referred to as "rear". Hereinafter, of the n characteristic units, the i-th characteristic unit counting from the front will be referred to as characteristic unit 20_i (i=1 to n). As an example, characteristic unit 20_1 corresponds to the first characteristic unit 3 in FIG. 2, characteristic unit 20_n corresponds to the second characteristic unit 5 in FIG. 2, and the other characteristic units 20_2, 20_3, ... correspond to one or more M-th characteristic units (M is an integer equal to or greater than 3) that are different from each other.

[0067] Furthermore, a plurality of time characteristic sections 4_1 to 4_n-1 are provided. The time characteristic section 4_1 corresponds to the time characteristic section 4 (first time characteristic section) in Fig. 1. The time characteristic sections 4_2, 4_3, etc. correspond to one or more P-th time characteristic sections (P is an integer of 2 or more) that are different from each other.

[0068] One or more Mth characteristic sections and one or more Pth time characteristic sections are arranged at least partially alternately between the time characteristic section 4_1 (corresponding to the time characteristic section 4 in Figure 1) and the characteristic section 20_n (corresponding to the second characteristic section 5 in Figure 2).

[0069] Although not shown in FIG. 6, the output section 8 is disposed after any one of the characteristic sections 20_i.

[0070] The characteristic section 20_i generates a characteristic H for a signal input from an arbitrary time characteristic section on the input side of the characteristic section 20_i, more specifically, for two signals (distortion signals) input according to time. i The characteristic H is given to the time characteristic section (separation characteristic section) on the output side and output to the time characteristic section (separation characteristic section). However, in the case of the characteristic section 20_1, signals (first signal, second signal) are input from the signal generating section 2. i performs an affine transformation on the frequency axis for the input signal.i causes linear distortion of the signal on the frequency axis. For example, the characteristic H i includes DC offset, which is a direct current noise component. i The P-th time characteristic section provides two signals (distortion signals) input from any characteristic section on the input side with different separation characteristics (time characteristics) and outputs the signals to the M-th characteristic section on the output side or the characteristic section at the final stage (characteristic section 20_n).

[0071] In the first embodiment, there are two characteristic parts that cause linear distortion in the signal, the first characteristic part 3 and the second characteristic part 5, but in the second embodiment, there are three or more characteristic parts that cause linear distortion in the signal. That is, there is one or more characteristic parts (excluding the time characteristic part, i.e., the separation characteristic part) other than the first characteristic part 3 and the second characteristic part 5. In the second embodiment, the characteristic H of any characteristic part 20_i i Estimate.

[0072] In this example, it is assumed that the characteristic section 20_1 corresponds to the first characteristic section 3 in Fig. 2, and the characteristic section 20_n corresponds to the second characteristic section 5 in Fig. 2, but this is not limiting. For example, the elements 31 to 33 included in the first characteristic section 3 may be treated as the characteristic sections 20_1 to 20_3, respectively. Alternatively, the characteristic section 20_i may be an additional element such as a filter arranged between any of the elements 2 to 6.

[0073] Hereinafter, the separation characteristic section that exists after the characteristic section 20_i will be referred to as the separation characteristic section 4_i. The separation characteristic section 4_i applies a separation characteristic D i Multiply by.

[0074] The separation characteristic portion 4_i may be arranged at least before or after the desired characteristic portion 20_i (excluding the characteristic portion 20_1 and the characteristic portion 20_n) whose characteristic is to be estimated. In other words, there are not necessarily n-1 separation characteristic portions 4_i. For example, if there is no need to estimate the characteristic H4 of the characteristic portion 20_4, the separation characteristic portions 4_3 and 4_4 may not be arranged. However, if there is a need to estimate the characteristic H5 of the characteristic portion 20_5, at least the separation characteristic portion 4_4 must be arranged.

[0075] The distortion estimation unit 6 estimates the characteristic of each characteristic unit 20_i, as in the first embodiment. As an example, the processing of the distortion estimation unit 6 when n=3 will be described. The following description also applies to the case where n≧4. When n=3, Z=H3D2H2D1H1X.

[0076] First, the separation characteristic section 4_1 sets the separation characteristic D1 as D p / D q As a result, the distortion estimation unit 6 acquires the signal Z1 and the signal Z2, Calculate TIFF0007808008000011.tif12170 and obtain the formula shown in Equation 9.

[0077]

number

[0078] From Equation 9, the characteristic H1 is estimated.

[0079] Next, the separation characteristic section 4_2 sets the separation characteristic D2 as D p / D q As a result, the distortion estimation unit 6 acquires the signal Z1 and the signal Z2, Calculate TIFF0007808008000013.tif13170 and obtain the formula shown in Equation 10.

[0080]

number

[0081] From Equation 10, the characteristic H3 is estimated.

[0082] Next, the distortion estimation unit 6 stops the function of the separation characteristic unit 4_1 to provide the separation characteristic (time characteristic), and the separation characteristic unit 4_2 provides the separation characteristic D2 as D p / D q Then, the distortion estimation unit 6 acquires the signal Z1 and the signal Z2 by switching between the two. Then, the distortion estimation unit 6 uses the already estimated characteristic H1 to obtain the following: TIFF0007808008000015.tif11170, and obtain an equation such as Equation 11. Since the separation characteristic part 4_1 is not functioning, the separation characteristic D1 is simply an identity matrix.

[0083]

number

[0084] The characteristic H2 is estimated from equation 11. Note that the order in which the distortion estimation unit 6 estimates the characteristics H1 to H3 is not limited to the above order. For example, the distortion estimation unit 6 may estimate the characteristic H2 at the point in time when it estimates the characteristic H1 or the characteristic H3. Furthermore, the equations for deriving each characteristic are not limited to the above equations.

[0085] As mentioned above, first, characteristic H1 or characteristic H n is then estimated. i Based on this, all the characteristics H i is estimated.

[0086] As described above, according to the second embodiment, even when there are three or more characteristic parts, it is possible to estimate the characteristic of any characteristic part.

[0087] (Third embodiment) 7 is a block diagram of a signal processing device 1B as an electronic device according to a third embodiment. Elements with the same names or functions as those in FIG. 1 of the first embodiment described above are assigned the same reference numerals. In addition to the signal processing device 1 according to the first embodiment, the signal processing device 1B includes a power amplifier (PA) 9 as an amplifier, and further includes a switching unit 10. Hereinafter, explanations will be omitted except for changes or additions. In the third embodiment, DPD is performed when a PA is included.

[0088] At least a part of the PA 9 and the switching unit 10 may be configured by a circuit or a processor, such as an application specific integrated circuit (ASIC) or a field-programmable gate array (FPGA), or some or all of these elements may be executed by a CPU that executes a program.

[0089] The PA9 amplifies the input signal. The PA9 is a compound semiconductor amplifier made of, for example, gallium nitride (GaN). When amplifying the signal, the PA9 applies a PA characteristic H PA and distorts the signal.

[0090] The switching unit 10 switches whether or not to feed back the output from the PA 9. The switching unit 10 includes a switch, and switches the connection by means of the switch. The switch can switch the connection between the input side and the output side of the PA 9.

[0091] First, the switching unit 10 switches the connection to the input side of the PA 9 so as not to feed back the output from the PA 9. In this state, as in the first embodiment, the distortion estimating unit 6 estimates the first characteristic H t Estimate.

[0092] Next, the switching unit 10 switches the connection to the output side of the PA 9 so as to feed back the output from the PA 9. In this state, the distortion estimating unit 6 estimates the first characteristic H t and PA characteristics H PA Estimate the product of

[0093] When the output from the PA9 is fed back, the first signal X1 is given the first distortion characteristic of the first characteristic section 3 and the characteristic of the PA9, and the signal H PA H t The seventh distortion signal X1 is input to the time characteristic section (separation characteristic section) 4. The second signal X2 is given the first distortion characteristic of the first characteristic section 3 and the characteristic of the PA 9 to generate a signal H PA H t X2 (the eighth distortion signal) is input to a time characteristic section (separation characteristic section) 4. Then, the distortion estimation unit 6 receives the signal Z1 (=H r D p H PA H t X1) and signal Z2 (=H r D q H PA H t The distortion estimation unit 6 obtains, for example, the following from the signal Z1 and the signal Z2: TIFF0007808008000017.tif11170 and obtain the formula shown in Equation 12.

[0094]

number

[0095] From Equation 12, the first characteristic H t and PA characteristics H PA Then, the distortion estimation unit 6 estimates the product of the first characteristic H t and the first characteristic H t and PA characteristics H PA From the product, the PA characteristic H PA Estimate.

[0096] The distortion compensation unit 7 calculates the first characteristic H estimated by the distortion estimation unit 6. t and PA characteristics H PA Specifically, the distortion compensation unit 7 applies a first characteristic H t Inverse matrix and PA characteristics H PA The signal generated by the signal generating unit 2 is a digital signal.

[0097] The distortion compensation unit 7 adjusts the PA characteristic H in real time at a constant frequency while the signal processing device 1B is in operation. PA It is desirable to compensate for the PA characteristic H PA To estimate the first characteristic H t The first characteristic H t Since the change in time is relatively slow, the first characteristic Ht The estimation of PA characteristics H PA In this case, for example, during operation of the signal processing device 1B, the distortion estimation unit 6 may estimate the first characteristic H t The processing load on the distortion estimation unit 6 may be reduced by reducing the frequency of estimation (or not estimating).

[0098] The output unit 8 outputs (transmits) the signal amplified by the PA 9. That is, the output unit 8 outputs a signal obtained by giving the first distortion characteristic to the signal (third signal) compensated by the distortion compensation unit 7 by the first characteristic unit and then amplified by the PA 9. If the output unit 8 includes an antenna, the output unit 8 radiates radio waves into space based on the signal amplified by the PA 9.

[0099] (Variation) 8 shows a modification of the third embodiment. In the above description, the PA 9 and the separation characteristic unit 4 are provided separately, but as already mentioned, the PA 9 may be used as the separation characteristic unit. When amplifying a signal, the PA 9 applies a PA characteristic H PA PA characteristic H PA is expressed as an NxN diagonal matrix and changes over time. PA The change per unit time of the first characteristic H t and the second characteristic H r The change per unit time of PA characteristic H is larger than that of PA is independent of the input signal. Therefore, the PA characteristic H PA also acts as the separation characteristic D.

[0100] For example, the distortion estimation unit 6 first calculates the PA characteristic H PA is treated as a separation characteristic D, and the first characteristic H t and the second characteristic H r Then, the distortion estimation unit 6 estimates the first characteristic H t , the second characteristic H r and PA characteristics H PA From the signal multiplied by, the first characteristic H t , the second characteristic H r By canceling the PA characteristic H PABy performing the processing in this manner by the distortion estimation unit 6, it is not necessary to newly add a separation characteristic unit 4, and DPD can be achieved with a simpler configuration.

[0101] 9 is a flowchart illustrating the processing performed by the signal processing device 1 B. The processing performed by the signal processing device 1 B will be described below with reference to FIG.

[0102] First, the switching unit 10 switches the connection to the input side of the PA 9 so as not to feed back the output from the PA 9, and the distortion estimating unit 6 calculates the first characteristic H t is estimated (step S21). Step S21 includes steps S11 to S15.

[0103] Next, the switching unit 10 switches the connection to the output side of the PA 9 so as to feed back the output from the PA 9, and the distortion estimating unit 6 calculates the first characteristic H t and PA characteristics H PA The product of is estimated (step S22).

[0104] Next, the distortion estimation unit 6 calculates the first characteristic H t and the first characteristic H t and PA characteristics H PA Based on the product of PA is estimated (step S23).

[0105] Next, the distortion compensation unit 7 calculates the estimated first characteristic H t and PA characteristics H PA Based on this, the signal generator 2 executes DPD to compensate the digital signal generated (step S24).

[0106] As described above, according to the third embodiment, DPD for a power amplifier can be performed regardless of the signal band.

[0107] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiments. For example, configurations in which some components are omitted from all the components shown in each embodiment may also be considered. Furthermore, components described in different embodiments may be appropriately combined.

[0108] This embodiment can also be configured as follows. [Item 1] a signal generating unit that generates a first signal and a second signal; a first characteristic unit that applies a first distortion characteristic to the first signal to obtain a first distorted signal, and applies the first distortion characteristic to the second signal to obtain a second distorted signal; a first time characteristic unit that applies a first time characteristic, which is a distortion characteristic that changes over time, to the first distortion signal to obtain a third distortion signal, and that applies a second time characteristic, which is a distortion characteristic that changes over time and is different from the first time characteristic, to the second distortion signal to obtain a fourth distortion signal; a second characteristic unit that applies a second distortion characteristic to the third distorted signal to obtain a fifth distorted signal, and applies the second distortion characteristic to the fourth distorted signal to obtain a sixth distorted signal; a distortion estimation unit that estimates at least one of the first distortion characteristic and the second distortion characteristic based on the first signal, the second signal, the fifth distortion signal, and the sixth distortion signal; An electronic device comprising: [Item 2] The distortion estimation unit estimating the first distortion characteristic by canceling the second distortion characteristic through a first calculation based on the first signal, the second signal, the fifth distortion signal, and the sixth distortion signal; and performing at least one of: estimating the second distortion characteristic by canceling the first distortion characteristic through a second calculation based on the first signal, the second signal, the fifth distortion signal, and the sixth distortion signal; Item 1. The electronic device according to item 1. [Item 3] The distortion estimation unit estimating the first distortion characteristic based on the eigenvector of the signal from which the second distortion characteristic has been cancelled; or estimating the second distortion characteristic based on the eigenvector of the signal from which the first distortion characteristic has been cancelled; Item 2. The electronic device according to item 2. [Item 4] the first distortion characteristic causes linear distortion on a frequency axis to the first signal and the second signal; The second distortion characteristic causes linear distortion on the frequency axis for the third distortion signal and the fourth distortion signal. The electronic device according to any one of items 1 to 3. [Item 5] the first distortion characteristic is determined by performing an affine transformation on the frequency axis for the first signal and the second signal; The second distortion characteristic is obtained by performing an affine transformation on the frequency axis for the third distortion signal and the fourth distortion signal. Item 4. The electronic device according to item 4. [Item 6] At least one of the first distortion characteristic and the second distortion characteristic includes an IQ imbalance. 6. The electronic device according to any one of items 1 to 5. [Item 7] the first time characteristic is a characteristic of the first distortion signal that varies over time in at least one of a phase, an amplitude, a frequency, and an impulse response; The second time characteristic is a characteristic that changes at least one of a phase, an amplitude, a frequency, and an impulse response of the second distortion signal over time. 7. The electronic device according to any one of items 1 to 6. [Item 8] the first distortion characteristic and the second distortion characteristic vary with time; The amount of change per unit time of the first distortion characteristic and the second distortion characteristic is smaller than the amount of change per unit time of the first time characteristic and the second time characteristic. The electronic device according to any one of items 1 to 7. [Item 9] the first time characteristic unit includes a plurality of devices that change at least one of a phase, an amplitude, a frequency, and an impulse response of a signal input to the first time characteristic unit; The first time characteristic section applies the first time characteristic to the first distorted signal and the second time characteristic to the second distorted signal by switching the plurality of devices according to time. The electronic device according to any one of items 1 to 8. [Item 10] the first time characteristic unit includes a frequency converter; the frequency converter imparts the first time characteristic to the first distorted signal by changing the amount of frequency shift imparted to the first distorted signal according to time, and imparts the second time characteristic to the second distorted signal by changing the amount of frequency shift imparted to the second distorted signal according to time; The frequency converter is part of the second characteristic unit. 10. The electronic device according to any one of items 1 to 9. [Item 11] The frequency converter is a mixer Item 11. The electronic device according to item 10. [Item 12] The mixer converts the frequency of a radio signal in the RF band to that in the BB band. Item 12. The electronic device according to item 11. [Item 13] The first time characteristic section includes a local oscillator that generates a local oscillation signal used by the mixer for frequency conversion, and imparts the first time characteristic to the first distortion signal and the second time characteristic to the second distortion signal by adding noise that varies with time to the local oscillation signal generated by the local oscillator. Item 13. The electronic device according to item 11 or 12. [Item 14] The first time characteristic unit includes an amplifier, and uses the amplifier to change at least one of the phase, the amplitude, the frequency, and the impulse response over time. Item 7. The electronic device according to item 7. [Item 15] Between the first time characteristic section and the second characteristic section, one or more different M-th characteristic sections (M is an integer of 3 or more) and one or more different P-th time characteristic sections (P is an integer of 2 or more) are at least partially alternately provided, the first characteristic unit outputs two signals, the first distortion signal and the second distortion signal, to the first time characteristic unit, and the first time characteristic unit outputs two signals, the third distortion signal and the fourth distortion signal, to the M characteristic unit on the output side of the first time characteristic unit; the M characteristic section imparts an M-th distortion characteristic to two distortion signals input from the first time characteristic section or the P time characteristic section on the input side of the M characteristic section, and outputs the signals to the P time characteristic section on the output side of the M characteristic section; the P time characteristic section imparts time characteristics, which are different distortion characteristics and which change over time, to the two distortion signals input from the M characteristic section on the input side of the P time characteristic section, and outputs the signals to the M characteristic section or the second characteristic section on the output side; The distortion estimation unit estimates the M distortion characteristic of at least one of the one or more different M characteristic units by switching between one or more different time characteristic units to disable a function among the one or more different P time characteristic units and the first time characteristic unit. Item 1. The electronic device according to item 1. [Item 16] At least one of the first characteristic unit and the second characteristic unit includes one or more filters that attenuate a signal of an arbitrary frequency component, and the first distortion characteristic or the second distortion characteristic is provided by the filter. The electronic device according to any one of items 1 to 15. [Item 17] a frequency band of the first signal is different from a frequency band of the fifth distorted signal; The frequency band of the second signal is different from the frequency band of the sixth distortion signal. 17. The electronic device according to any one of items 1 to 16. [Item 18] an amplifier connected to an output of the first characteristic unit and amplifying a signal; a switch that selectively connects the input of the first time characteristic unit to either the input or the output of the amplifier, the distortion estimation unit connects the switch to an input of the amplifier and estimates the first distortion characteristic; The switch is connected to the output of the amplifier, and a seventh distortion signal obtained by applying the first distortion characteristic and the characteristic of the amplifier to the first signal, and an eighth distortion signal obtained by applying the first distortion characteristic and the characteristic of the amplifier to the second signal are input to the first time characteristic unit, thereby estimating a product of the first distortion characteristic and the characteristic of the amplifier, and estimating the characteristic of the amplifier based on the estimated product and the estimated first distortion characteristic. The electronic device according to any one of items 1 to 17. [Item 19] a distortion compensator that compensates for a third signal generated by the signal generator based on the first distortion characteristic and amplifier characteristic estimated by the distortion estimator; an output unit that outputs a signal obtained by giving the first distortion characteristic to the third signal compensated by the distortion compensator by the first characteristic unit and amplified by the amplifier; Further equipped Item 19. The electronic device according to item 18. [Item 20] The output unit includes an antenna that transmits radio waves based on the signal. Item 19. The electronic device according to item 19. [Item 21] generating a first signal; generating a second signal; imparting a first distortion characteristic to the first signal to obtain a first distorted signal, and imparting the first distortion characteristic to the second signal to obtain a second distorted signal; a first time characteristic, which is a distortion characteristic that changes over time, is given to the first distortion signal to obtain a third distortion signal; and a second time characteristic, which is a distortion characteristic that changes over time and is different from the first time characteristic, is given to the second distortion signal to obtain a fourth distortion signal; imparting a second distortion characteristic to the third distorted signal to obtain a fifth distorted signal, and imparting the second distortion characteristic to the fourth distorted signal to obtain a sixth distorted signal; and estimating at least one of the first distortion characteristic and the second distortion characteristic based on the first signal, the second signal, the fifth distortion signal, and the sixth distortion signal. Signal processing methods. [Explanation of symbols]

[0109] 1, 1A, 1B Signal processing device (electronic device) 2. Signal Generation Section 3. Transmission signal processing section (first characteristic section) 4,4_1~4_n-1 Time characteristic part (separation characteristic part) 5 LB signal processing section (second characteristic section) 6 Distortion estimation section 7 Distortion compensation section 8 Output section 9. Power Amplifier (PA) 10 Switching section 20_1~20_n characteristic part 31 D / A converter 32 Modulator 33 Mixer 41 Frequency converter 42 Separation characteristics switching section 43 Device switching unit 44 Equipment 51 A / D converter 52 Demodulator 53 Mixer

Claims

1. a signal generating unit that generates a first signal and a second signal; a first characteristic unit that applies a first distortion characteristic to the first signal to obtain a first distorted signal, and applies the first distortion characteristic to the second signal to obtain a second distorted signal; a first time characteristic unit that applies a first time characteristic, which is a distortion characteristic that changes over time, to the first distortion signal to obtain a third distortion signal, and that applies a second time characteristic, which is a distortion characteristic that changes over time and is different from the first time characteristic, to the second distortion signal to obtain a fourth distortion signal; a second characteristic unit that applies a second distortion characteristic to the third distortion signal to obtain a fifth distortion signal, and applies the second distortion characteristic to the fourth distortion signal to obtain a sixth distortion signal; a distortion estimation unit that estimates the first distortion characteristic and the second distortion characteristic individually and separately from a product state of the first distortion characteristic and the second distortion characteristic based on the first signal, the second signal, the fifth distortion signal, and the sixth distortion signal; An electronic device comprising:

2. The distortion estimation unit estimating the first distortion characteristic by canceling the second distortion characteristic through a first calculation based on the first signal, the second signal, the fifth distortion signal, and the sixth distortion signal; and performing at least one of: estimating the second distortion characteristic by canceling the first distortion characteristic through a second calculation based on the first signal, the second signal, the fifth distortion signal, and the sixth distortion signal; The electronic device of claim 1 .

3. The distortion estimation unit estimating the first distortion characteristic based on the eigenvector of the signal from which the second distortion characteristic has been cancelled; or estimating the second distortion characteristic based on the eigenvector of the signal from which the first distortion characteristic has been cancelled; 3. The electronic device of claim 2.

4. the first distortion characteristic causes linear distortion on a frequency axis to the first signal and the second signal; The second distortion characteristic causes linear distortion on the frequency axis for the third distortion signal and the fourth distortion signal. The electronic device of claim 1 .

5. the first distortion characteristic is determined by performing an affine transformation on the first signal and the second signal on a frequency axis; The second distortion characteristic is obtained by performing an affine transformation on the frequency axis for the third distortion signal and the fourth distortion signal.

5. The electronic device of claim 4.

6. At least one of the first distortion characteristic and the second distortion characteristic includes an IQ imbalance. The electronic device of claim 1 .

7. The first time characteristic is a characteristic of the first distortion signal that varies over time in at least one of a phase, an amplitude, a frequency, and an impulse response; The second time characteristic is a characteristic that changes at least one of a phase, an amplitude, a frequency, and an impulse response of the second distortion signal over time. The electronic device of claim 1 .

8. the first distortion characteristic and the second distortion characteristic vary with time; The amount of change per unit time of the first distortion characteristic and the second distortion characteristic is smaller than the amount of change per unit time of the first time characteristic and the second time characteristic. The electronic device of claim 1 .

9. the first time characteristic unit includes a plurality of devices that change at least one of a phase, an amplitude, a frequency, and an impulse response of a signal input to the first time characteristic unit; The first time characteristic unit applies the first time characteristic to the first distorted signal and the second time characteristic to the second distorted signal by switching the plurality of devices according to time. The electronic device of claim 1 .

10. The second characteristic unit includes a frequency converter, The first time characteristic unit controls the frequency converter included in the second characteristic unit, changing an amount of frequency shift to be applied to the first distorted signal according to time, thereby giving the first distorted signal the first time characteristic; changing the amount of frequency shift to be applied to the second distorted signal according to time, thereby giving the second distorted signal the second time characteristic; The electronic device of claim 1 .

11. The frequency converter is a mixer The electronic device of claim 10.

12. The mixer converts the frequency of a radio signal in the RF band into the BB band.

12. The electronic device of claim 11.

13. The first time characteristic section includes a local oscillator that generates a local oscillation signal used by the mixer for frequency conversion, and adds noise that changes over time to the local oscillation signal generated by the local oscillator, thereby imparting the first time characteristic to the first distortion signal and imparting the second time characteristic to the second distortion signal.

12. The electronic device of claim 11.

14. The first time characteristic unit includes an amplifier, and uses the amplifier to change at least one of the phase, the amplitude, the frequency, and the impulse response over time.

8. The electronic device of claim 7.

15. Between the first time characteristic section and the second characteristic section, one or more different M-th characteristic sections (M is an integer of 3 or more) and one or more different P-th time characteristic sections (P is an integer of 2 or more) are at least partially alternately provided, the first characteristic unit outputs two signals, the first distortion signal and the second distortion signal, to the first time characteristic unit, and the first time characteristic unit outputs two signals, the third distortion signal and the fourth distortion signal, to the M characteristic unit on the output side of the first time characteristic unit; the M characteristic section imparts an Mth distortion characteristic to two distortion signals input from the first time characteristic section or the P time characteristic section on the input side of the M characteristic section, and outputs the signals to the P time characteristic section on the output side of the M characteristic section; the P time characteristic section imparts time characteristics, which are different distortion characteristics and which change with time, to the two distortion signals input from the M characteristic section on the input side of the P time characteristic section, and outputs the signals to the M characteristic section or the second characteristic section on the output side; The distortion estimation unit estimates the M distortion characteristic of at least one of the one or more different M characteristic units by switching between one or more different time characteristic units to disable a function among the P time characteristic units and the first time characteristic unit. The electronic device of claim 1 .

16. At least one of the first characteristic unit and the second characteristic unit includes one or more filters that attenuate a signal of an arbitrary frequency component, and the first distortion characteristic or the second distortion characteristic is provided by the filter. The electronic device of claim 1 .

17. a frequency band of the first signal is different from a frequency band of the fifth distortion signal; The frequency band of the second signal is different from the frequency band of the sixth distortion signal. The electronic device of claim 1 .

18. an amplifier connected to an output of the first characteristic unit and amplifying a signal; a switch that selectively connects an input of the first time characteristic unit to either an input or an output of the amplifier, the distortion estimation unit connects the switch to an input of the amplifier and estimates the first distortion characteristic; The switch is connected to the output of the amplifier, and a seventh distortion signal obtained by applying the first distortion characteristic and the characteristic of the amplifier to the first signal, and an eighth distortion signal obtained by applying the first distortion characteristic and the characteristic of the amplifier to the second signal are input to the first time characteristic unit, thereby estimating a product of the first distortion characteristic and the characteristic of the amplifier, and estimating the characteristic of the amplifier based on the estimated product and the estimated first distortion characteristic. The electronic device of claim 1 .

19. a distortion compensator that compensates for a third signal generated by the signal generator based on the first distortion characteristic and amplifier characteristic estimated by the distortion estimator; an output unit that outputs a signal obtained by giving the first distortion characteristic to the third signal compensated by the distortion compensator by the first characteristic unit and amplified by the amplifier; Further equipped 20. The electronic device of claim 18.

20. The output unit includes an antenna that transmits radio waves based on the signal.

20. The electronic device of claim 19.

21. generating a first signal; generating a second signal; imparting a first distortion characteristic to the first signal to obtain a first distorted signal, and imparting the first distortion characteristic to the second signal to obtain a second distorted signal; a first time characteristic, which is a distortion characteristic that changes over time, is given to the first distortion signal to obtain a third distortion signal; and a second time characteristic, which is a distortion characteristic that changes over time and is different from the first time characteristic, is given to the second distortion signal to obtain a fourth distortion signal; imparting a second distortion characteristic to the third distorted signal to obtain a fifth distorted signal, and imparting the second distortion characteristic to the fourth distorted signal to obtain a sixth distorted signal; The first distortion characteristic and the second distortion characteristic are individually separated and estimated from a product state of the first distortion characteristic and the second distortion characteristic based on the first signal, the second signal, the fifth distortion signal, and the sixth distortion signal. Signal processing methods.

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