JP6086582B2 - High frequency power amplifier and transmitter using high frequency power amplifier - Google Patents

Description

  The present invention relates to a non-linear distortion compensation technique for reducing a non-linear distortion component output from a transmission apparatus that performs wireless radio wave power amplification by a power amplifier.

  An example of a conventional nonlinear distortion compensation technique, in particular, a technique of a predistortion compensation system is disclosed in Patent Document 1. In the conventional technique, it is easy to compensate for third-order distortion, fifth-order distortion, and seventh-order distortion, which are symmetrical distortions on the frequency axis generated by the power amplifier, but it is difficult to compensate for asymmetric distortion on the frequency axis.

However, in class AB amplification of a MOS-FET with high power efficiency, a lot of distortion asymmetric on the frequency axis occurs (see Non-Patent Document 1).
By the way, since the MOS-FET conducts only by applying a voltage between the source and the gate, the transient response in the turn-on direction is fast, but the conduction continues until the gate charge is extracted, so the transient response in the turn-off direction is Become slow. For this reason, the asymmetric distortion becomes large above and below the time axis waveform, and the asymmetric distortion also becomes large above and below the frequency axis. Furthermore, the MOS-FET has a conduction resistance that changes with temperature.
Incidentally, even in the Si-MOS structure, like a charge multiplying CCD, electrons are trapped in the gate electrode in proportion to the integrated amount of the product of the gate electric field and the transfer charge due to the charge multiplying gate electrode voltage, and the characteristics deteriorate ( Non-patent document 8).
In addition, in GaN, electrons are trapped in the gate electrode in proportion to the integrated amount of the gate electric field due to the drain electrode voltage, and the conduction resistance deteriorates (see Non-Patent Document 9).
These changes and deteriorations are collectively referred to as memory distortion.

Wide-band SiGe-LNA of 40 to 900MHz with a feedback circuit (see Non-Patent Document 2), GaN-HEMT with high output and high-efficiency and high-voltage operation at 40 to 500-6000MHz (see Non-Patent Document 3) and 2700- GaN-HEMT (see Non-Patent Document 4), which is 400W at 2900MHz, high output, high efficiency and high voltage operation, has been commercialized, and GaN-MOSFET has been developed. In addition, Si-MOSFETs having the same performance as GaN-MOSFETs have been developed (see Non-Patent Document 11 and Non-Patent Document 12).
In addition, the 7680H × 4320V UHDTV uses 1500MHz video signal in parallel to perform gamma processing to increase dark area amplification and lower light area amplification, and contour correction processing to compensate for the transient response of the subject contour. The number of parallels is being reduced using a high-speed FPGA (see Non-Patent Document 5 and Non-Patent Document 6). A 2500 MHz 14-bit DAC has also been commercialized for mobile phone base stations (see Non-Patent Document 7). A digital television transmitter using a dynamic reconfigurable IC faster than a high-speed FPGA has also been commercialized (see Non-Patent Document 10).

WO 2004/045067

Toshiba Review 2004Vol.59No.2, p34-p40, Digital Terrestrial Broadcasting Transmitter Panasonic VHF / UHF compatible low noise amplifier AN26072A, http://panasonic.co.jp/corp/news/official.data/data.dir/jn110315-1/jn110315-1.html Mitsubishi Electric MGF0846G http://www.mitsubishielectric.co.jp/news-data/2010/pdf/0722-a.pdf Sumitomo Electric EGN28B400M1B-R http://www.sedi.co.jp/pdf/EGN28B400M1B-R_ED1-0.pdf StratixV from Altera http://www.altera.co.jp/products/devices/stratix-fpgas/stratix-v/stxv-index.jsp Xilinx Virtex-7 HT http://www.xilinx.com/products/virtex7/index.htm Analog Devices 2.5Gbps 14bitDACAD9739A http://www.analog.com/static/imported-files/data_sheets/AD9739A.pdf TI TC246RGB-B0 680x500PIXEL IMPACTRONTM PRIMARY COLOR CCD CCD IMAGE SENSOR SOCS087-DECEMBER 2004-REVISED MARCH 2005 Nikkei Electronics 2011.08.22 p67-p76 (p74) Nikkei Electronics 2011.08.22 p59-p66 (p62) Nikkei Electronics 2011.09.05 p18 Evolving Si Power Device Approaching GaN in terms of characteristics Freescale RF LDMOS power transistor MRFE6V8600H http://cache.freescale.com/files/rf_if/doc/data_sheet/MRFE6VP8600H.pdf?fsrch=1&sr=3

  An object of the present invention is to stably compensate and reduce distortion generated in a power amplifier.

  In order to achieve the above object, the present invention digitally modulates an input signal to convert it to a baseband input digital modulation signal of the I axis and the Q axis, and upconverts the sampling to 8 times the high frequency center frequency. A linearizer that adds an inverse characteristic of the nonlinearity of the power amplifier and an inverse characteristic of the transient response of the power amplifier in the turn-on direction and an inverse characteristic of the transient response in the turn-off direction. A transient response compensator, a D / A, an LNA in a band of at least eight times the high frequency center frequency, and a power amplifier in a band of at least four times the high frequency center frequency. Add, add the reverse characteristics of the transient response in the turn-on direction of the power amplifier and the reverse characteristics of the transient response in the turn-off direction, D / A, and LNA and high frequency in a band more than 8 times the high frequency center frequency Bands more than 4 times the center frequency A high frequency power amplifier using the distortion compensation, characterized in that the amplification in the power amplifier.

And a modulation unit that digitally modulates the input signal to generate a baseband input digital modulation signal of the I-axis and the Q-axis, and an upconverter that upconverts the sampling to 8 times the high-frequency center frequency. A linearizing unit for adding the reverse characteristic of the power, a transient response compensating unit for adding the reverse characteristic of the transient response in the turn-on direction and the reverse characteristic of the transient response in the turn-off direction of the power amplifier, and D / A It consists of an LNA with a frequency band more than 8 times the center frequency of the high frequency (stabilization of amplification such as internal feedback and AGC) and a power amplifier with a band frequency of more than 4 times the center frequency of the high frequency (stabilization of amplification level such as AGC). Add the inverse characteristics of the nonlinearity of the power amplifier, add the inverse characteristics of the transient response of the power amplifier in the turn-on direction and the inverse characteristics of the transient response in the turn-off direction, D / A, and the high frequency center frequency LNA with more than 8 times the bandwidth Linearization adds the amplifying four times more bandwidth of the power amplifier of the RF center frequency, separately and Push-side signal and the Pull-side signal and an inverse characteristic of the inverse characteristic static nonlinearity of the power amplifier A transient response compensator for individually adding the reverse characteristic of the transient response in the turn-on direction and the reverse characteristic of the transient response in the turn-off direction of the power amplifier, A, an LNA (amplification stabilization of internal feedback, AGC, etc.) 8 times or more of the high frequency center frequency, and a power amplifier (amplification stabilization of AGC, etc.) of a band more than 4 times the high frequency center frequency, The push-side signal and the pull-side signal are individually added to the static nonlinear inverse characteristics of the power amplifier, and the push-side signal and the pull-side signal are individually added to the turn-on direction of the power amplifier. Add the reverse characteristics of the transient response and the reverse characteristics of the transient response in the turn-off direction, D / A, Amplifying with a power amplifier with a band of 8 times or more of the number and a power amplifier with a band of 4 or more of the high-frequency center frequency, and adding the inverse characteristics of the nonlinearity of the power amplifier, the transient response of the power amplifier in the turn-on direction A linearizer that adds the inverse characteristics of the transient response and the inverse characteristics of the transient response in the turn-off direction, an adder that adds the delay signal , a D / A, and a compound semiconductor in a band of 16 times or more of the high-frequency center frequency An exciter with a band of 8 times or more of the high frequency center frequency (consisting of HEMT) and a power amplifier (made of a GaN-MOSFET or Super Junction Si MOSFET) with a band of 8 or more times the high frequency center frequency And the feedback circuit of the attenuator such as a resistor, add the inverse characteristics of the nonlinearity of the power amplifier, and the inverse characteristics of the transient response in the turn-on direction and the transient response in the turn-off direction of the power amplifier. Are added, the delay signal is added, D / A, and (high frequency center frequency Amplified and fed back with an exciter with a bandwidth of 8 times or more of the high-frequency center frequency and a power amplifier (made of MOSFET) with a bandwidth of 8 or more times the high-frequency center frequency. and adding the output of the (signal processing and the first stage LNA and the next-stage LNA and power amplifier) signal the up-converting delayed delay amount of the feedback direct resistance to the current output D / a input, Push-side signal Pull a linearization unit for adding the inverse characteristic of the static non-linearity of the side signal and the individual power amplifiers, Push-side signal and the Pull-side signal and the turn-on direction transient response of the individual power amplifier and inverse characteristic and the transient response compensation unit for adding the inverse characteristic of the turn-off direction of the transient response, an adder for adding the delayed signal, and a D / a, (the band of 16 times or more the frequency center frequency HEMT of Excited in a band more than 8 times the high frequency center frequency It has a vibrator, a power amplifier (consisting of a MOSFET) with a bandwidth of 8 times the high frequency center frequency, and a feedback circuit for an attenuator such as a resistor. Push side signal and Pull side signal are powered separately Add the inverse characteristics of the static nonlinearity of the amplifier, and push-side and pull-side signals separately for the reverse characteristics of the transient response in the turn-on direction and the transient response in the turn-off direction of the power amplifier. Characteristics, add delay signal, D / A, exciter and high frequency center frequency of 8 times higher frequency center frequency (consisting of HEMT of 16 times higher frequency center frequency) Amplified and fed back by a power amplifier (consisting of a MOSFET) having a bandwidth of 8 times or more of the above, and delayed by an amount of delay (between signal processing, first-stage LNA, next-stage LNA, and power amplifier) for direct feedback by a resistor Adding the upconverted signal to the current output D / A input;
A linearization unit that adds the inverse characteristics of static nonlinearity of the power amplifier separately to Class C Push and Class C Pull, and a transient in the turn-on direction of the power amplifier separately from Class C Push and Class C Pull. and transient response compensation unit for adding the inverse characteristic and turn-off direction of the response and an inverse characteristic of the transient response, and D / a, and exciter 8 times more bands of high-frequency center frequency, class C Push and class C A power amplifier with Pull,
A linearizer that adds class AB Push and class AB Pull separately to the inverse characteristics of the static nonlinearity of the power amplifier, and class AB Push and class AB Pull separately for the power amplifier turn-on transient and transient response compensation unit for adding the inverse characteristic and turn-off direction of the response and an inverse characteristic of the transient response, an adder for adding the delayed signal, D / a and the excitation of 8 times or more of the band of the RF center frequency A power amplifier of class AB Push and class AB Pull with a band of 8 times or more of the high frequency center frequency, and a feedback circuit of an attenuator such as a resistor,
Class C Push and Class C Pull are individually added to the inverse characteristics of the static nonlinearity of the power amplifier,
Add the inverse characteristics of the transient response in the turn-on direction and the transient response in the turn-off direction of the power amplifier separately for Class C Push and Class C Pull, D / A, and 8 times the center frequency of the high frequency Amplify with an exciter in the above band and a power amplifier in a band more than 8 times the center frequency of the high frequency. Add the class AB Push and class AB Pull separately to the inverse characteristics of the static nonlinearity of the power amplifier.
Add the reverse characteristics of the transient response in the turn-on direction and the transient response in the turn-off direction of the power amplifier separately for class AB Push and class AB Pull, add the delay signal, D / A, Amplifying and feeding back with an exciter with a bandwidth of 8 times or more of the high frequency center frequency and a power amplifier of class AB Push and AB with a bandwidth of 8 times or more of the high frequency center frequency Adding the upconverted signal delayed by the delay of the first stage LNA, the next stage LNA, and the power amplifier to the current output D / A input;
A high frequency power amplifier using distortion compensation characterized by at least one of the above.

Further, a linearization unit for adding the inverse characteristic of the static non-linearity of the Push-side signal and the Pull-side signal and individually power amplifier, Push-side signal and the Pull-side signal and the individually power amplifier turn- a transient response compensator that adds the reverse characteristics of the transient response in the on direction and the reverse characteristics of the transient response in the turn-off direction, an adder that adds the delay signal, and D / A (16 times the high frequency center frequency) An exciter with a band of 8 times or more of the high frequency center frequency (consisting of HEMT of the above band), a power amplifier with a band of 8 times or more of the high frequency center frequency (comprising a MOSFET), and attenuation of resistance, etc. The push-side signal and the pull-side signal are individually added to the static non-linear inverse characteristics of the power amplifier, and the push-side signal and the pull-side signal are individually powered. Add the reverse characteristic of the transient response in the turn-on direction and the reverse characteristic of the transient response in the turn-off direction, add the delay signal, D / A, an exciter with a band of 8 times or more of the high frequency center frequency (configured with HEMT of a band of 16 times or more of the high frequency center frequency) and a MOSFET (with MOSFET of 8 times or more of the high frequency center frequency). The above-mentioned up-converted signal delayed by the delay (with signal processing, first stage LNA, next stage LNA, and power amplifier) of the output that is amplified and fed back by the power amplifier and directly fed back by the resistor is the push side signal and the pull side signal. The transmitter is characterized in that a high frequency power amplifier using distortion compensation added to the current output D / A input in reverse phase is used, and the digital modulation is OFDM modulation.

  Furthermore, (broadcast transmitter) In the transmitter described above, the OFDM modulation is OFDM modulation with a guard interval, and the input signal is a TS signal.

  As described above, according to the present invention, it is possible to stably compensate and reduce distortion generated in the power amplifier.

The block diagram which shows the whole structure of the broadcasting machine of Class A amplification of one Example of this invention (RF predistortion compensation of linear compensation and transient response compensation) The block diagram which shows the whole structure of the broadcasting apparatus of PushPull output composition of one example of the present invention (RF predistortion compensation of linear compensation and transient response compensation) 1 is a block diagram showing the overall configuration of a class A amplification broadcaster according to an embodiment of the present invention (RF Digital Feed Back in which predistortion compensation for linear compensation and transient response compensation is placed before a loop). 1 is a block diagram showing the overall configuration of a push-pull output synthesis broadcaster according to an embodiment of the present invention (RF Digital Feedback Back placed before an RF predistortion compensation loop for linear compensation and transient response compensation). 1 is a block diagram showing the overall configuration of a push-pull output synthesis broadcaster according to an embodiment of the present invention (RF Digital Feedback Back placed before an RF predistortion compensation loop for linear compensation and transient response compensation). The block diagram which shows the whole structure of the broadcasting apparatus of PushPull output composition of one Example of this invention (RF Digital Feed Back which puts predistortion compensation of linear compensation and transient response compensation before a loop) 1 is a block diagram showing the overall configuration of a push-pull output synthesis broadcaster according to an embodiment of the present invention (RF Digital Feedback Back placed before an RF predistortion compensation loop for linear compensation and transient response compensation). Block diagram showing the overall configuration of a push-pull output synthesis broadcaster of one embodiment of the present invention (improves efficiency with class C push-pull and reduces distortion with feed back with class AB push-pull) Block diagram showing the configuration of transient response compensation Block diagram showing configuration of transient response compensation including transient response enhancement signal Schematic diagram of transient response compensation for class A amplification (schematic diagram of transient response compensation in FIG. 1A or FIG. 1C and FIG. 2A) Schematic diagram of transient response compensation including transient response emphasis signal of class A amplification (Schematic diagram of transient response compensation when turn-off delay is large in FIG. 1A or FIG. 1C and FIG. 2B) Schematic diagram of class AB amplification transient response compensation for push and pull output synthesis (schematic diagram of transient response compensation in Fig. 1B or Fig. 1D and Fig. 2A, similar operation for push and pull) Schematic diagram of transient response compensation including transient response emphasis signal of class AB amplification of push and pull output synthesis (schematic diagram of transient response compensation with large turn-off delay in Fig. 2B) Flow chart of transient response compensation operation Flow chart of transient response compensation operation including transient response enhancement signal

  Modulate the input digital video signal into a baseband input digital modulation signal of I axis and Q axis, upconvert to 4 times the sampling of the high frequency center frequency, add the inverse characteristic of the nonlinearity of the power amplifier, The inverse characteristics of the transient response are added, the current output is D / A, amplified by the first-stage LNA, the next-stage LNA, and the power amplifier, and the power amplifier output is directly fed back to the first-stage LNA with a resistor. The up-converted signal delayed by the delay of the output directly fed back by the resistor (the signal processing, the first stage LNA, the next stage LNA, and the power amplifier) is added to the current output D / A input.

  FIG. 1A is a block diagram showing an overall configuration of a broadcasting apparatus according to an embodiment of the present invention including linear compensation and RF predistortion compensation for transient response compensation, and FIG. 1B is a diagram showing RF pre-RF for linear compensation and transient response compensation. FIG. 1C is a block diagram showing an overall configuration of a broadcasting apparatus according to an embodiment of the present invention for predistortion, and FIG. 1C is a diagram of Hybrid Feed Back of the present invention in which predistortion for linear compensation and transient response compensation is placed before a loop. FIG. 1D is a block diagram showing an overall configuration of a broadcasting apparatus according to an embodiment, and FIG. 1D is an entire broadcasting apparatus according to an embodiment of the present invention of RF Digital Feed Back placed before an RF predistortion compensation loop for linear compensation and transient response compensation. FIG. 1E is a block diagram showing a configuration, and FIG. 1E is an entire broadcasting apparatus of an RF Digital Feed Back according to an embodiment of the present invention in which push-pull is separated by an isolator placed before an RF predistortion compensation loop for linear compensation and transient response compensation. It is a block diagram which shows a structure.

  1A to 1E, 1 is an MPEG encoder (ENC) that converts SDI into TS, 2 is an OFDM / QAM quadrature modulator (I / QMOD) that converts TS into I / Q signals, and 3 is an I / Q signal. Is converted to 8 times the output carrier wave and suppresses the peak (UpCon), 4 is a class A amplification pre-linearizer that operates at 8 times the output carrier wave (linear distortion correction), 4A is Class AB push-pull preamplifier (distortion inverse correction) linearizer that operates at 8 times the output carrier. 5 is a class A amplification pre-transient response inverse corrector (Transient Compensator) that operates at 8 times the output carrier, and 5A and 5B are class AB amplification pre-transient response inverse correctors (at 8 times the output carrier). Transient Compensator), 6 and 6A and 6B are digital / analog converters (DACs) that operate at 8 times the output carrier, and 7 and 7A, 7B, 8, 8A and 8B operate at frequencies up to 8 times from the output carrier. (Stabilization of amplification such as internal feedback and AGC) Amplifiers (LNA), 7C, 7D, 7E, 8C, 8D, and 8E are amplifiers (LNA) that operate at a frequency up to 16 times from the output carrier wave. 9 is a class A amplified high power amplifier (Power Amp: PA) that operates at a frequency up to 4 times from the output carrier, and 9A and 9B are class AB amplified high power amplifiers that operate at a frequency up to 4 times from the output carrier ( Power Amp (PA) (Many parallel connections), 9C is a class A amplified high-power amplifier (Power Amp: PA) that operates at a frequency up to 8 times the output carrier, 9D and 9E are up to 8 times from the output carrier This is a class AB amplification high power amplifier (Power Amp: PA) (often connected in parallel) operating at a frequency of Reference numerals 10, 10 </ b> A and 10 </ b> B are detectors operating on the output carrier, 11, 11 </ b> A and 11 </ b> B are directional couplers operating on the output carrier, 12 is a band pass filter (BPF) operating on the output carrier, 13 Is an antenna that operates on the output carrier wave.

  1A to 1E, 14 and 14A and 14B are push-pull synthesizers that operate at a frequency up to four times the output carrier, and 15A, 15B, 15C, and 15D are delay units that operate at eight times the output carrier ( Delay), 16 and 16A and 16B are adders operating at 8 times the output carrier. 17 is a metal film resistor that operates at a frequency up to 8 times from the output carrier (in many series connection), 18A is a buffer that operates at 8 times the output carrier, and 18B is an inverting buffer that operates at 8 times the output carrier. (Inverter), 19A and 19B are isolators that operate at a frequency up to four times from the output carrier wave.

2A is a block diagram showing a configuration of transient response compensation, and FIG. 2B is a block diagram showing a configuration of transient response compensation including a transient response enhancement signal.
2A and 2B, reference numeral 40 denotes a rise / fall determination, a delay amount selection unit, 41 denotes a transient response enhancement signal generation unit, and 43 denotes a transient response correction unit. M1, M2, M3, M4, M5, M6: Delays (Delay) that operate at 8 times the output carrier, N0, N1, N2, N4, N5, N6: Inverting amplifiers that operate at 8 times the output carrier, P3 : An amplifier that operates at 8 times the output carrier wave. 45, 46, 47, 48, 49, 50 and 51 are adders which operate at 8 times the output carrier wave.

3A is a schematic diagram of the transient response compensation operation of FIG. 2A in FIG. 1A or FIG. 1C of class A amplification, and FIG. 3B is the Turn-off delay of FIG. 2A in FIG. 1A or FIG. It is a schematic diagram of the operation | movement of the transient response compensation containing many transient response emphasis signals.
3C is a schematic diagram of the transient response compensation operation of FIG. 2A in FIG. 1B or FIG. 1D of class AB amplification for combining the push side output and the pull side output , and FIG. 3D synthesizes the push side output and the pull side output. in Figure 1B or Figure 1D class AB amplifier that is a schematic view of the operation of the transient response compensation including the Turn-off delay is often transient response enhancement signal in Figure 2B.

4A is a flowchart of the transient response compensation operation of FIG. 2A and corresponds to the operations of FIGS. 3A and 3C. FIG. 4B is a flowchart of the transient response compensation operation including the transient response enhancement signal with a large Turn-off delay of FIG. 2B, and corresponds to the operations of FIGS. 3B and 3D.
The present invention will be described below.

Utilizing the speedup of the elements of each non-patent document of the background art, D / A that operates at a frequency eight times that of a high-frequency output carrier, internal feedback that operates at a frequency up to eight times from the high-frequency output carrier, AGC, etc. Using an amplifier (LNA) with a stabilized amplification factor and a power amplifier that operates at a frequency up to four times the frequency of the high-frequency output carrier wave, the inverse characteristics of the nonlinearity of the power amplifier and the inverse characteristics of the transient response are represented in the high-frequency digital domain. Pre-compensation with. The output of the power amplifier is detected via a directional coupler, and AGC is applied to stabilize the high-frequency output level.
Hereinafter, FIG. 1A of a block diagram showing the overall configuration of the broadcasting apparatus of one embodiment of the present invention with linear compensation and RF predistortion compensation of transient response compensation, and FIG. 2A of the block diagram showing the configuration of transient response compensation, or FIG. 2B is a block diagram showing the configuration of the transient response compensation including the transient response enhancement signal, and FIG. 3A is a schematic diagram of the transient response compensation of the class A amplification or the transient response compensation including the transient response enhancement signal of the class A amplification. 3B of the schematic diagram and FIG. 4A of the flowchart of the transient response compensation operation or FIG. 4B of the flowchart of the transient response compensation operation including the transient response enhancement signal will be described.

As shown in Fig. 3A in the schematic diagram of transient response compensation, the turn-on is fast for the turn-on, so no compensation, and the turn-off for the turn-off has a large or slightly slow compensation. Replace with a signal with less delay.
Therefore, as indicated by 22 in FIG. 4A in the flowchart of the transient response compensation operation, using the delay signals 0d to 6d in FIGS. 2A to 2B and the parameters A and B corresponding to the turn-off time in FIGS. 3A to 3D, 3d and 4d are compared, and if 3d ≦ 4d , 3d is selected as 25.
Then, if 3d> 4d, 3d and 4d + A are compared as in 23, and if 3d ≦ 4d + A , 2d is selected as in 26. Further, if 3d> 4d + A, 3d is compared with 4d + A + B as in 24, and if 3d ≦ 4d + A + B , 1d is selected as in 27. If 3d> 4d + A + B, 0d is selected as in 28.

Alternatively, as shown in FIG. 3B of the schematic diagram of transient response compensation including a transient response emphasizing signal, the turn-on is fast for the turn-on, so there is no compensation, and the turn-off for the turn-off. In order to compensate more or less slowly, the signal is replaced with a signal with less delay, and the difference between the preceding and following signals is added.
Therefore, as indicated by 22 in FIG. 4B in the flowchart of the transient response compensation operation including the transient response enhancement signal, the delay signals 0d to 6d in FIGS. 2A to 2B and the parameters corresponding to the turn-off time in FIGS. 3A to 3D are used. 3d and 4d are compared using parameters K and L corresponding to the turn-off time when A, B and C and the transient response emphasis signal are included, and 3d is selected as 25 if 3d ≦ 4d .
When 3d> 4d, 4d and 5d are compared as in 30, and when 4d ≦ 5d , 1d is selected as output as 31. If 4d> 5d, 0d is selected for output as in 32, and 4d-5d is added.
Further, 4d and 5d + B are compared as in 33, and if 4d ≦ 5d + B, the process ends. If 4d> 5d + B, K is subtracted from the output as in 34.
Also, 4d and 5d + B + C are compared as in 35, and if 4d ≦ 5d + B + C, the process ends. If 4d> 5d + B + C, L is subtracted from the output as in 36, and the process ends.

A modulation unit that digitally modulates a TS signal obtained by compressing a video signal to form a baseband input digital modulation signal of the I axis and the Q axis, and an upconverter that upconverts the sampling to 8 times the high frequency center frequency. A linearizer for adding the inverse characteristics of the nonlinearity of the amplifier, a transient response compensator for adding the inverse characteristics of the transient response of the power amplifier in the turn-on direction and the inverse characteristics of the transient response in the turn-off direction, and D / A, an LNA in a band of 8 times or more of the high-frequency center frequency, and a power amplifier in a band of 4 or more times the high-frequency center frequency, adding the inverse characteristics of the nonlinearity of the power amplifier, Add the inverse characteristics of the transient response in the on direction and the reverse characteristics of the transient response in the turn-off direction, and perform D / A to obtain an LNA in a band that is at least 8 times the high frequency center frequency and a band that is at least 4 times the high frequency center frequency. Amplify with power amplifier
The effect of the first embodiment is that the linearizer compensates for the non-linearity of static distortion to an inverse characteristic. The Transient Compensator compensates for the reverse characteristics of the MOS-FET transient response added to the input signal to compensate for the fact that the MOS-FET is turn-on fast but the turn-off is slow until the gate charge is extracted. Or 4fsc
The Transient Compensator delays the input signal by 2 NClk in 1Clk units, subtracts the preceding and following signals from the NClk delayed signal, and adds the inverse characteristics of the transient response to the input signal as in the case of camera edge enhancement. It is simply compensating for the transient response.
The first embodiment is suitable for low-power broadcasting of orthogonal modulation waves such as single QAM in the VHF low frequency band.

FIG. 1B is a block diagram showing the overall configuration of a broadcasting apparatus according to an embodiment of the present invention for linear predistortion and transient response compensation RF predistortion, and a transient response of class AB amplification that synthesizes a push side output and a pull side output. Only differences from the first embodiment will be described with reference to FIG. 3C of the schematic diagram of compensation or FIG. 3D of the schematic diagram of transient response compensation including the transient response enhancement signal of class AB amplification that synthesizes the push side output and the pull side output . To do.
2A of the block diagram showing the configuration of the transient response compensation or FIG. 2B of the block diagram showing the configuration of the transient response compensation including the transient response enhancement signal, and FIG. 4A of the flowchart of the transient response compensation operation or the transient response enhancement signal. 4B of the flowchart of the operation of the included transient response compensation is the same as in the first embodiment.

Fig. 3C Schematic diagram of transient response compensation of class AB amplification that synthesizes push side output and pull side output . Schematic of transient response compensation including transient response enhancement signal of class AB amplification that synthesizes push side output and pull side output. In FIG. 3D, the push-side signal and the pull-side signal are individually added to the static nonlinear inverse characteristics of the power amplifier, and the push-side signal and the pull-side signal are individually added to the turn- Add the inverse characteristics of the transient response in the on direction and the transient response in the turn-off direction to pre-compensate the inverse characteristics of the nonlinearity of the power amplifier and the inverse characteristics of the transient response in the high frequency digital domain. .

A linearization unit for adding the inverse characteristic of the static non-linearity of the Push-side signal and the Pull-side signal and individually power amplifier, turn-on direction of the Push-side signal and the Pull-side signal and individually power amplifier A transient response compensator for adding the inverse characteristics of the transient response and the inverse characteristics of the transient response in the turn-off direction, a D / A, an LNA in a band more than eight times the high frequency center frequency, and a high frequency center frequency of 4 It has a power amplifier with a bandwidth of more than double, and push side signal and pull side signal are individually added to the inverse characteristics of static non-linearity of power amplifier, and push side signal and pull side signal are individually Add the reverse characteristics of the transient response of the power amplifier in the turn-on direction and the reverse characteristics of the transient response in the turn-off direction, and perform D / A to obtain an LNA and a high-frequency center frequency that are at least eight times the high-frequency center frequency. Is amplified by a power amplifier with a bandwidth of 4 times or more.

Effect of Embodiment 2, the Transient Compensator is that the MOS-FET is fast turn-on slower to turn-off is withdrawn gate charge, individually and Push-side signal and the Pull-side signal, MOS-FET transient The inverse characteristic of the response is added to the input signal to compensate.
The second embodiment is suitable for low-power broadcasting of an orthogonal modulation wave having a peak power larger than the average power of OFDM or the like in the VHF low frequency band.

Hybrid with pre-distortion pre-distortion compensation for linear and transient response compensation
Only the differences between the first embodiment and the second embodiment will be described with reference to FIG. 1C of the block diagram showing the overall configuration of the broadcasting apparatus of the first embodiment of the present invention of Feed Back.
2A of the block diagram showing the configuration of the transient response compensation or FIG. 2B of the block diagram showing the configuration of the transient response compensation including the transient response enhancement signal, and FIG. 4A of the flowchart of the transient response compensation operation or the transient response enhancement signal. 4B of the flowchart of the operation of the included transient response compensation is the same as that of the first embodiment.

Using the speedup of the elements of each non-patent document of the background art, an amplifier (LNA) that operates at a frequency up to 16 times from the high-frequency output carrier and has a delay of 1/16 of the high-frequency output carrier period, and 8 from the high-frequency output carrier The power amplifier operates at a frequency up to twice, and the delay is 1/8 of the high frequency output carrier cycle, and the total delay is 1/4 of the high frequency output carrier cycle. Is pre-compensated in the high frequency digital domain.
Furthermore, using the fact that the total delay is as small as 1/4 of the high frequency output carrier cycle, the output of the power amplifier is directly fed back to the amplifier (LNA) input by a resistor, and the output of the output directly fed back by the resistor (signal processing and first stage LNA and The up-converted signal delayed by the delay of the next stage LNA and the power amplifier is added to the current output D / A input. Since the feedback amount directly fed back by the resistor is small, the resistance value of the feedback resistor is higher than that of the characteristic resistor, so that the power rating may be small and there is no need for impedance conversion of the feedback path.

Add the inverse characteristic of the nonlinearity of the power amplifier, add the delay signal and the linearizer that adds the inverse characteristic of the transient response of the power amplifier in the turn-on direction and the inverse characteristic of the transient response in the turn-off direction An adder, a D / A, an exciter having a band of 8 times or more of the high frequency center frequency (configured by GaN-HEMT having a band of 16 times or more of the high frequency center frequency), and 8 times or more of the high frequency center frequency. Power amplifier (consisting of GaN-MOSFET) and feedback circuit of attenuator such as a resistor, adding the inverse characteristics of the nonlinearity of the power amplifier, and the transient response of the power amplifier in the turn-on direction And reverse characteristics of turn-off direction transient response are added, delayed signal is added, D / A is performed, and high frequency (consisting of GaN-HEMT with a bandwidth of 16 times higher than the high frequency center frequency) It consists of an exciter with a bandwidth 8 times higher than the center frequency and a GaN-MOSFET with a bandwidth 8 times higher than the high frequency center frequency The up-converted signal delayed by the delay (with signal processing, first stage LNA, next stage LNA, and power amplifier) of the output that is amplified and fed back by the power amplifier and directly fed back by the resistor is the current output D / A. Add to input.

The effect of the third embodiment is that the feedback loop delay is as short as a quarter cycle of 100 MHz, 2.5 ns, is stable, and asymmetric distortion is reduced by predistortion of linear and transient response. It is only necessary to increase the gain and bandwidth.
The third embodiment is suitable for broadcasting of orthogonal modulation waves such as single QAM in the VHF low frequency band.

Example 1 to Example 3 using FIG. 1D of a block diagram showing the overall configuration of a broadcasting apparatus of an RF digital feed back of an embodiment of the present invention of RF Digital Feed Back placed before an RF predistortion compensation loop of linear compensation and transient response compensation Only differences from the above will be described.
2A of the block diagram showing the configuration of the transient response compensation or FIG. 2B of the block diagram showing the configuration of the transient response compensation including the transient response enhancement signal, and FIG. 4A of the flowchart of the transient response compensation operation or the transient response enhancement signal. 4B of the flowchart of the operation of the included transient response compensation is the same as that of the first embodiment.
Fig. 3C Schematic diagram of transient response compensation of class AB amplification that synthesizes push side output and pull side output . Schematic of transient response compensation including transient response enhancement signal of class AB amplification that synthesizes push side output and pull side output. FIG. 3D is the same as that of the second embodiment.

A Push-side signal and the Pull-side signal by adding the inverse characteristic of the static non-linearity of the individual power amplifiers, Push-side signal and the Pull-side signal and the individually power amplifier turn-on direction of the transient response of the The inverse characteristic and the inverse characteristic of the transient response in the turn-off direction are added, and the inverse characteristic of the nonlinearity of the power amplifier and the inverse characteristic of the transient response are pre-compensated in the high frequency digital domain.
Furthermore, using the fact that the total delay is as small as 1/4 of the high frequency output carrier cycle, it is combined with the Push side signal and Pull side signal, and the output of the power amplifier is directly fed back to the amplifier (LNA) input with a resistor, and directly with the resistor The up-converted signal delayed by the delay of the output to be fed back (with signal processing, first-stage LNA, next-stage LNA, and power amplifier) is added to the current output D / A input in the opposite phase to the push-side signal and the pull-side signal. To do.

A linearization unit for adding the inverse characteristic of the static non-linearity of the Push-side signal and the Pull-side signal and individually power amplifier, turn-on direction of the Push-side signal and the Pull-side signal and individually power amplifier and transient response compensation unit for adding the inverse characteristic of the transient response of the reverse characteristic and turn-off direction of the transient response of an adder for adding the delayed signal, and a D / a, of more than 16 times (RF center frequency An exciter with a bandwidth of 8 times or more of the high frequency center frequency (composed of GaN-HEMT in the bandwidth), a power amplifier with a bandwidth of 8 times or more of the high frequency center frequency (composed of GaN-MOSFET), a resistance, etc. the attenuator comprises a feedback circuit, adds the inverse characteristic of the static non-linearity of the Push-side signal and the Pull-side signal and individually power amplifier, individually and Push-side signal and the Pull-side signal Add the reverse characteristic of the transient response in the turn-on direction and the reverse characteristic of the transient response in the turn-off direction of the power amplifier, add the delay signal, / A and an exciter with a bandwidth of 8 times or more of the high frequency center frequency (consisting of GaN-HEMT with a bandwidth of 16 times or more of the high frequency center frequency) and a GaN-MOSFET with a bandwidth of 8 times or more of the high frequency center frequency (GaN-MOSFET) The up-converted signal delayed by the delay (with signal processing, first-stage LNA, next-stage LNA, and power amplifier) of the output that is amplified and fed back by a power amplifier (directly fed back) and directly fed back by a resistor. Add to the / A input .

The effect of the fourth embodiment is that the push side output and the pull side output are mixed by synthesis and fed back by a feedback circuit of an attenuator such as a resistor (signal processing, first stage LNA, next stage LNA, and power amplifier). The up-converted signal delayed by the delay amount is corrected by adding it in the opposite phase to the push-side signal and the pull-side signal, and the operation is stable.
The fourth embodiment is suitable for wide-area broadcasting of orthogonal modulation waves having a peak power larger than the average power of OFDM or the like in the VHF low frequency band.

FIG. 1E of the block diagram showing the entire configuration of the broadcasting apparatus of the RF digital feed back according to the first embodiment of the present invention in which the push-pull is separated by the isolator placed before the RF predistortion compensation loop of the linear compensation and the transient response compensation. Only differences from the first to fourth embodiments will be described.
2A of the block diagram showing the configuration of the transient response compensation or FIG. 2B of the block diagram showing the configuration of the transient response compensation including the transient response enhancement signal, and FIG. 4A of the flowchart of the transient response compensation operation or the transient response enhancement signal. 4B of the flowchart of the operation of the included transient response compensation is the same as that of the first embodiment.
Fig. 3C Schematic diagram of transient response compensation of class AB amplification that synthesizes push side output and pull side output . Schematic of transient response compensation including transient response enhancement signal of class AB amplification that synthesizes push side output and pull side output. FIG. 3D is the same as that of the second embodiment.

As an alternative when the isolator is small and low-priced, the power amplifier output, push side output, and pull side output are separated by the isolator, and the push side signal and the pull side signal are individually separated by resistors. Add direct feedback and reverse characteristics of static non-linearity of power amplifier, and push-side signal and pull-side signal separately for power amplifier turn-on direction transient response and turn-off direction Add the inverse characteristics of the transient response.

A linearization unit for adding the inverse characteristic of the static non-linearity of the Push-side signal and the Pull-side signal and individually power amplifier, turn-on direction of the Push-side signal and the Pull-side signal and individually power amplifier and transient response compensation unit for adding the inverse characteristic of the transient response of the reverse characteristic and turn-off direction of the transient response of an adder for adding the delayed signal, and a D / a, of more than 16 times (RF center frequency An exciter with a bandwidth of 8 times or more of the high frequency center frequency (composed of GaN-HEMT in the bandwidth), a power amplifier with a bandwidth of 8 times or more of the high frequency center frequency (composed of GaN-MOSFET), a resistance, etc. the attenuator comprises a feedback circuit, adds the inverse characteristic of the static non-linearity of the Push-side signal and the Pull-side signal and individually power amplifier, individually and Push-side signal and the Pull-side signal Add the reverse characteristic of the transient response in the turn-on direction and the reverse characteristic of the transient response in the turn-off direction of the power amplifier, add the delay signal, / A and an exciter with a bandwidth of 8 times or more of the high frequency center frequency (consisting of GaN-HEMT with a bandwidth of 16 times or more of the high frequency center frequency) and a GaN-MOSFET with a bandwidth of 8 times or more of the high frequency center frequency (GaN-MOSFET) The output of the output (signal processing, first-stage LNA, next-stage LNA, and power amplifier) that is amplified by a power amplifier, separated by an isolator, separated from the Push-side output and Pull-side output, and directly fed back by a resistor. ) Add the up-converted signal delayed by the delay to the current output D / A input.

The effect of the fifth embodiment is that although two isolators are required and the configuration is complicated, the push-side signal and the pull-side signal can be individually controlled, and distortion can be further reduced.
The fifth embodiment is suitable for wide-area broadcasting of orthogonal modulation waves having a peak power larger than the average power of OFDM or the like in the VHF low frequency band.

  FIG. 1F is a block diagram showing an overall configuration of a broadcaster of an RF Digital Feed Back according to an embodiment of the present invention, in which push-pull is separated by an isolator placed before an RF predistortion compensation loop for linear compensation and transient response compensation. Only differences from the first to fifth embodiments will be described.

The difference from FIG. 1C of Example 3 is that the feedback is a single PA.
As in the third embodiment, the sixth embodiment is suitable for broadcasting of quadrature modulation waves such as single QAM in the VHF low frequency band.

RF Digital Feed placed before RF predistortion compensation loop for linear compensation and transient response compensation
Only differences from the first to sixth embodiments will be described with reference to FIG. 1G which is a block diagram showing the overall configuration of a broadcasting apparatus according to one embodiment of the present invention.

The difference from FIG. 1D of the fourth embodiment is that the feedback is a single PA.
As in the fourth embodiment, the seventh embodiment is suitable for wideband broadcasting of orthogonal modulation waves having a peak power larger than the average power of OFDM or the like in the VHF low frequency band.

  Example 1 to Example Using FIG. 1G of a block diagram showing the overall configuration of a broadcasting apparatus of one example of the present invention that improves efficiency with Class C Push-pull and reduces distortion with Class AB Push-pull with Feed Back Only differences from 7 will be described.

The difference from FIG. 1G in Example 7 is that the efficiency is improved by class C push-pull, and the distortion is reduced by feed back by class AB push-pull.
As in the seventh embodiment, the eighth embodiment is suitable for wideband broadcasting of orthogonal modulation waves having a peak power larger than the average power of OFDM or the like in the VHF low frequency band.

  As described above, the present invention reduces the distortion factor of a wideband transmitter in the VHF low frequency band by combining RF predistortion compensation and RF feedback, and wideband broadcasting in the VHF low frequency band. Suitable for

1: MPEG encoder (ENC) that converts SDI to TS,
2: OFDM / QAM quadrature modulator (I / QMOD) that converts TS into I / Q signal;
3: Converter (UpCon) that converts the I / Q signal to 8 times the output carrier wave and suppresses the peak.
4: Pre-class A amplification (reverse distortion correction) linearizer that operates at 8 times the output carrier.
4A: Class AB push-pull amplification predistortion (distortion inverse correction) linearizer that operates at 8 times the output carrier wave,
5: Transient Compensator for class A amplification operating at 8 times the output carrier, Transient Compensator,
5A, 5B: class AB amplification pre-transient response inverse compensator (Transient Compensator) operating at 8 times the output carrier,
6, 6A, 6B: Digital / analog converter (DAC) operating at 8 times the output carrier wave,
7, 7A, 7B, 8, 8A, 8B: an amplifier (LNA) that operates at a frequency up to 8 times from the output carrier wave (internal feedback, stabilization of amplification such as AGC),
7C, 7D, 7E, 8C, 8D, 8E: an amplifier (LNA) operating at a frequency from the output carrier to 16 times,
9: Class A amplified high-power amplifier (Power Amp: PA) operating at a frequency up to 4 times from the output carrier wave,
9A, 9B: Class AB amplification high power amplifier (PA) operating at a frequency up to 4 times from the output carrier wave,
9C: Class A amplified high power amplifier (PA) operating at a frequency up to 8 times from the output carrier wave,
9D, 9E: Class AB amplification high power amplifier (PA) operating at a frequency of 8 times from the output carrier wave,
10, 10A, 10B: detectors operating on the output carrier wave,
11, 11A, 11B: Directional couplers operating on the output carrier wave,
12: Band pass filter (BPF) operating on the output carrier,
13: Antenna operating with output carrier wave (Antenna),
14, 14A, 14B: push-pull synthesizer operating at a frequency up to 4 times from the output carrier wave,
15A, 15B, 15C, 15D: delay units that operate at 8 times the output carrier wave (Delay),
16, 16A, 16B, 45, 46, 47, 48, 49, 50, 51: an adder operating at 8 times the output carrier wave,
17: Metal film resistor operating at a frequency up to 8 times from the output carrier wave (many in series connection)
18A: Buffer that operates at 8 times the output carrier wave,
18B: Inverter that operates at 8 times the output carrier wave,
19A, 19B: Isolators operating at a frequency up to 4 times from the output carrier wave,
40: rise / fall determination, delay amount selection unit,
41: Transient response emphasis signal generator,
43: Transient response correction unit,
M1, M2, M3, M4, M5, M6: Delays that operate at 8 times the output carrier wave (Delay),
N0, N1, N2, N4, N5, N6: an inverting amplifier operating at 8 times the output carrier wave,
P3: an amplifier that operates at 8 times the output carrier wave,

Claims (4)

A modulation unit that digitally modulates an input signal to form a baseband input digital modulation signal of the I-axis and the Q-axis, and an upconverter that upconverts the sampling to 8 times the high-frequency center frequency,
A linearizer that adds the inverse characteristics of the nonlinearity of the power amplifier, a transient response compensator that adds the inverse characteristics of the transient response in the turn-on direction and the inverse characteristics of the transient response in the turn-off direction, A D / A, an LNA in a band more than 8 times the high frequency center frequency, and a power amplifier in a band more than 4 times the high frequency center frequency,
Add the inverse characteristics of the nonlinearity of the power amplifier, add the inverse characteristics of the transient response in the turn-on direction and the inverse characteristics of the transient response in the turn-off direction, D / A, and A high-frequency power amplifier using distortion compensation, wherein amplification is performed by an LNA having a band of 8 times or more and a power amplifier having a band of 4 times or more of a high-frequency center frequency. A modulation unit that digitally modulates an input signal to form a baseband input digital modulation signal of the I-axis and the Q-axis, and an upconverter that upconverts the sampling to 8 times the high-frequency center frequency,
Furthermore, a linearization unit that adds the push-side signal and the pull-side signal individually to the inverse characteristics of the static nonlinearity of the power amplifier, and the push-side signal and the pull-side signal are individually turned- A transient response compensator that adds the reverse characteristics of the transient response in the on direction and the reverse characteristics of the transient response in the turn-off direction, a D / A, and a band of at least eight times the high frequency center frequency (internal feedback, AGC, etc. (Amplification stabilization of AGC) LNA and a power amplifier (amplification stabilization of AGC, etc.) in a band more than four times the center frequency of the high frequency,
A Push-side signal and the Pull-side signal by adding the inverse characteristic of the static non-linearity of the individual power amplifiers, Push-side signal and the Pull-side signal and the individually power amplifier turn-on direction of the transient response of the The inverse characteristic and the inverse characteristic of the transient response in the turn-off direction are added, D / A, and amplified by an LNA in a band of 8 times or more of the high frequency center frequency and a power amplifier in a band of 4 or more of the high frequency center frequency. high frequency power amplifier using the distortion compensation, characterized in that. A linearization unit that individually adds the push-side signal and the pull-side signal to the inverse characteristic of the static nonlinearity of the power amplifier;
A transient response compensator that adds the reverse characteristics of the transient response in the turn-on direction and the reverse characteristics of the transient response in the turn-off direction to the push side signal and the pull side signal, and an adder that adds the delay signal And D / A, an exciter having a band of 8 times or more of the high frequency center frequency (configured by HEMT having a band of 16 times or more of the high frequency center frequency), and a MOSFET having a band of 8 or more times of the high frequency center frequency (MOSFET Power amplifier, and a feedback circuit for the attenuator such as a resistor. Push side signal and Pull side signal are individually added to the inverse characteristics of static nonlinearity of the power amplifier. The push-side signal and the pull-side signal are individually added with the reverse characteristic of the transient response in the turn-on direction and the reverse characteristic of the transient response in the turn-off direction, and the delay signal is added. However, excitation of a band of 8 times or more of the high frequency center frequency (consisting of HEMT of a band of 16 times or more of the high frequency center frequency) The output is amplified and fed back by a power amplifier (consisting of a MOSFET) with a bandwidth of 8 times or more of the center frequency of the vibrator and directly fed back by a resistor (with signal processing, first-stage LNA, next-stage LNA, and power amplifier. ) Using a high-frequency power amplifier using distortion compensation that adds the delayed up-converted signal to the current output D / A input in phase opposite to the push-side signal and the pull-side signal, and the digital modulation is referred to as OFDM modulation. A transmitter characterized by.   4. The transmitter according to claim 3, wherein the OFDM modulation is OFDM modulation with a guard interval, and the input signal is a TS signal.

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