JP2016072779A - Digital wireless mic receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interference-resistant digital wireless mic receiver capable of being stably used even when pulse disturbance is generated.SOLUTION: A receiver comprises: a complex signal demodulation unit 26 for performing demodulation to obtain a complex signal from a reception signal; a time deinterleave unit 27; an elimination section determination unit 80; an error correction decoding unit 29; and an information source decoding unit 25. Error correction decoding is performed after elimination processing for making a section in which the reception is disturbed by a pulse noise be zero.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a receiver for a digital wireless microphone, that is, a receiver for a wireless microphone system that digitizes an audio signal and wirelessly transmits the signal. In particular, the present invention employs an OFDM digital transmission method using digital modulation / demodulation, interleaving, and error correction. The present invention relates to a wireless microphone receiver.

  In recent years, research and development of digital wireless microphones that can transmit and receive audio with high quality has been promoted. Among them, OFDM (Orthogonal Frequency Division) that is resistant to multipath and fading, and can efficiently use a limited frequency band. Wireless microphones that transmit and receive using a Multiplexing (orthogonal frequency division multiplexing) modulation / demodulation method are drawing attention.

  FIG. 12 is a block diagram of the basic configuration of an OFDM digital wireless microphone. Non-Patent Document 1 defines a standard for a specific radio microphone, and the OFDM digital wireless microphone in FIG. 12 has a configuration conforming to the standard.

  12A includes an information source encoding unit 12, a transmission path encoding unit 13, a frequency conversion unit 14, a power amplification unit 15, and a transmission antenna. 12B includes a reception antenna, a reception amplification unit 22, a frequency conversion unit 23, a transmission path decoding unit 24, and an information source decoding unit 25.

  Here, on the transmission side, the information source encoding unit 12 converts an analog audio signal into a digital signal, compresses the audio signal, and multiplexes additional information. The transmission path encoding unit 13 modulates the digital signal output from the information source encoding unit 12 into an OFDM modulated signal and transmits the modulated signal. The receiving side basically performs the reverse process of the transmitting side.

  The configuration of the information source encoding unit and the information source decoding unit is selected according to the compression method of the audio signal to be transmitted. For example, when an uncompressed linear PCM (pulse code modulation) audio signal is handled, the information source encoding unit is constituted by an AD (analog / digital) conversion unit, and the information source decoding unit is constituted by a DA (digital / analog) conversion unit. When compression of only the amplitude direction called instantaneous companding is used for an audio signal, the information source encoding unit is an AD conversion unit and an amplitude compression unit, and the information source decoding unit is an amplitude expansion unit and a DA conversion unit. Composed. Also, when data compression is performed on an audio signal by ADPCM (adaptive differential pulse code modulation), the information source encoding unit is an AD conversion and ADPCM encoder, and the information source decoding unit is , Composed of ADPCM decoder and DA conversion.

  FIG. 13 is a block diagram illustrating a configuration of the transmission path encoding unit 13 of the transmission apparatus in FIG. 12A (Non-Patent Document 1).

  The transmission path encoding unit 13 includes an energy spreading unit 31, an error correction encoding unit 32, a carrier modulation unit 33 including a bit rotation unit 34 and a mapping unit 35, a frequency interleaving unit 36, and a time interleaving unit 37. An OFDM frame configuration unit 40, an IFFT (Inverse Fast Fourier Transform) unit 41, and a guard interval adding unit 42. Among these configurations, the carrier modulation unit 33 to the guard interval addition unit 42 constitute an OFDM modulation unit.

  Hereinafter, each component will be described.

  The energy spreading unit 31 randomizes the signal transmitted from the information source coding unit 12 using a pseudo-random signal or the like so that the energy is not concentrated on a specific carrier of OFDM due to the deviation of the voice information.

  The error correction coding unit 32 performs convolutional coding at a predetermined coding rate (for example, 1/2 or 2/3). Note that outer code encoding by adding parity bits or the like can be performed in the information source encoding unit as necessary.

  The carrier modulation unit 33 rearranges the data input from the error correction coding unit 32 in the bit unit without causing a time delay in the bit rotation unit 34, and then the carrier in the mapping unit 35 Every time, mapping to the IQ plane is performed according to a predetermined modulation method (modulation multilevel number M), and a carrier modulation signal is generated and output to the frequency interleaving unit 36.

  The frequency interleaving unit 36 rearranges the carrier numbers of originally adjacent symbols and distributes the data in frequency in order to improve the tolerance when a specific carrier wave is disturbed. The data rearranged so as to be dispersed in frequency is output to the time interleaving unit 37.

  The time interleaving unit 37 disperses data in time by changing the order of signals (complex signals) transmitted sequentially. This is effective as a countermeasure against pulse noise and the like which will be described later.

  The OFDM frame configuration unit 40 generates an OFDM frame by inserting and arranging the pilot signal 38 and the TMCC signal 39 with respect to the signal input from the time interleaving unit 37, and outputs the OFDM frame to the IFFT unit 41. Since the amplitude and phase at the time of signal generation are known, the pilot signal 38 is used to estimate transmission path characteristics on the receiving side. The pilot signal includes an SP (Scattered Pilot) signal arranged in a distributed manner and a CP (Continual Pilot) signal arranged continuously in the symbol direction. A TMCC (Transmission and Multiplexing Configuration Control) signal transmits control information.

  The IFFT unit 41 performs an IFFT (Inverse Fast Fourier Transform) process on the OFDM frame input from the OFDM frame configuration unit 40 to generate an IFFT output signal in an effective symbol period. The generated IFFT output signal is output to the guard interval adding unit 42.

  The guard interval adding unit 42 inserts a guard interval obtained by copying the latter half of the IFFT output signal at the head of the IFFT output signal in the effective symbol period input from the IFFT unit 41. The guard interval is inserted in order to reduce intersymbol interference when receiving an OFDM signal, and is set so that the delay time of the multipath delay wave does not exceed the guard interval length.

  In this way, an OFDM transmission signal is created and transmitted via the frequency conversion unit 14 and the power amplification unit 15.

  FIG. 14 is a block diagram illustrating a configuration of the transmission path decoding unit 24 of the receiving apparatus in FIG. 12B, and performs processing reverse to that of the transmission side transmission path encoding unit 13 (Non-Patent Document 1). .

  The transmission path decoding unit 24 includes a window processing unit 51, an FFT (Fast Fourier Transform) unit 52, an OFDM frame demultiplexing unit 53, an interpolation filter unit 54, a complex division unit 55, and a time de-interleaver. Unit 56, frequency de-interleave unit 57, carrier demodulation unit 58 including de-mapping unit 59 and bit de-interleave unit 60, error correction decoding unit 61, and energy despreading unit 62. Among these configurations, the OFDM demodulating unit is configured from the window processing unit 51 to the carrier demodulating unit 58.

  Hereinafter, each component will be described.

  The window processing unit 51 receives the OFDM reception signal from the frequency conversion unit 23, removes the guard interval from the OFDM reception signal, and extracts the signal in the effective symbol period.

  The FFT unit 52 performs FFT (Fast Fourier Transform) processing on the signal from which the guard interval has been removed to restore the OFDM frame signal.

  The OFDM frame demultiplexing unit 53 separates and extracts a carrier symbol signal and a pilot signal that are effective as data from the OFDM frame signal, outputs the pilot signal to the interpolation filter unit 54, and is a carrier symbol signal that is effective as data. Is output to the complex division unit 55.

  The interpolation filter unit 54 calculates the transmission channel characteristics of the carrier in which the pilot signal exists by comparing the amplitude and phase after reception of the pilot signal with a reference value (known amplitude and phase), and calculates the calculated transmission. The channel characteristics are interpolated in the time direction and the frequency direction to obtain transmission path information (CSI: Channel State Information) which is information about the transmission path characteristics corresponding to all OFDM carrier symbols.

  The complex division unit 55 performs complex division on the carrier symbol signal as data extracted from the OFDM frame demultiplexing unit 53 by transmission path information (CSI) corresponding to each carrier symbol obtained by the interpolation filter unit 54. A data signal (Data: complex signal S) in which distortion in the transmission path is corrected is obtained.

  The time de-interleaving unit 56 performs time de-interleaving processing on the corrected complex signal S, and returns the data whose time order is rearranged on the transmission side to the original order.

  The frequency de-interleaving unit 57 further performs frequency de-interleaving processing to restore the data rearranged in terms of frequency on the transmission side.

  The carrier demodulating unit 23 demodulates the signal input from the frequency de-interleaving unit 57 for each carrier and outputs the demodulated signal to the error correction decoding unit 61. When demodulating, the de-mapping unit 59 demodulates the complex signal S (I signal value and Q signal value) into bit-unit data, and the bit de-interleave unit 60 arranges the bit unit on the transmission side. Return the replaced data to the original array.

  The error correction decoding unit 61 performs error correction processing such as Viterbi decoding on the signal input from the carrier demodulation unit 58. Note that soft-decision decoding that also considers data reliability can be performed for error correction decoding.

  The energy despreading unit 62 performs energy despreading to return to the original signal output and outputs it to the information source decoding unit 25.

  In this way, the reception apparatus performs the reverse process of the transmission path encoding unit 13 in the transmission path decoding unit 24, and then performs the information source decoding process.

  Next, a countermeasure against the pulse noise of the above-described OFDM digital wireless microphone will be described.

  The 1.2 GHz band in which a specific radio microphone (wireless microphone) is used is shared with a radio orientation station, and is expected to receive pulsed interference. As the interference wave, for example, a strong pulse having a pulse width of about 150 μsec is repeatedly emitted with a period of about 5 to 10 msec. Therefore, even an OFDM modulation / demodulation wireless microphone may generate noise due to strong pulsed interference.

  FIG. 15 is a diagram showing an example of the relationship between OFDM symbols and pulse noise used in a digital wireless microphone. For example, when transmission / reception is performed using an OFDM modulation / demodulation method with a symbol length of 83.3 μsec, when a strong pulse wave (pulse noise) with a pulse width of 150 μsec enters the reception input, two to three OFDM symbols The data (A) extending over the range is affected, and in some cases, the sound is interrupted (noise such as popping or zapping) due to pulsed interference.

  Therefore, in order to avoid the influence of such interference, time interleaving is adopted. Time interleaving is a device for recovering data by subsequent error correction even when there is interference with a group of data at a certain moment with pulse noise.

  FIG. 16 shows a state where time deinterleaving is performed on the reception side with respect to a signal subjected to time interleaving on the transmission side. As shown in FIG. 16, for the carrier symbol (A) whose reliability has been lost due to the interference of pulse noise, the receiving side receives the interference by returning the data to the original arrangement by time deinterleaving. The data can be distributed and then recovered by error correction. Therefore, the combination of time interleaving and error correction coding processing is a countermeasure against pulse noise.

  Such time interleaving can be employed not only in the OFDM modulation / demodulation system but also in a single carrier transmission / reception apparatus.

  FIG. 17 is a block diagram showing a basic configuration of a digital wireless microphone transmission / reception apparatus including a single carrier.

  FIG. 17A shows a basic configuration on the transmission side of a digital wireless microphone that performs time interleaving. The transmission apparatus 11 includes an information source encoding unit 12, an error correction encoding unit 16, a carrier modulation unit 17, a time interleaving unit 18, a complex signal modulation unit 19, a power amplification unit 15, and a transmission antenna. Including at least. This configuration can be applied to a single-carrier digital wireless microphone. At the same time, when the complex signal modulation unit 19 is made to correspond to an OFDM frame configuration unit, an IFFT unit, and the like, an OFDM modulation / demodulation type digital wireless microphone is also included. It is a simple configuration.

  The audio signal from the microphone is converted into a digital signal by the information source encoding unit 12, and the information source is compressed as necessary. The output signal from the information source encoding unit 12 is encoded by the error correction encoding unit 16 and then IQ-mapped by the carrier modulation unit 17 to be converted into a complex signal. The complex signal is input to the time interleaving unit 18, and the order of the signals is rearranged so that the pulse interference is dispersed in the time interleaving unit 18, and the data is dispersed in time. The output signal from the time interleaving unit 18 is modulated from a complex signal to a transmission signal by the complex signal modulation unit 19, passes through the power amplification unit 15, and is radiated from the transmission antenna.

  FIG. 17B shows a basic configuration of the receiving side of the digital wireless microphone that performs time deinterleaving. The reception device 21 includes a reception antenna, a reception amplification unit 22, a complex signal demodulation unit 26, a time de-interleaving unit 27, a carrier demodulation unit 28, an error correction decoding unit 29, and an information source decoding unit 25. Including at least. This configuration can be applied to a single-carrier digital wireless microphone. At the same time, if the complex signal demodulation unit 26 is made compatible with an IFFT unit and an OFDM frame demultiplexing unit, an OFDM modulation / demodulation digital wireless microphone is also included. This is a general configuration.

  A signal from the reception antenna is amplified by the reception amplification unit 22 and input to the complex signal demodulation unit 26. The complex signal demodulator 26 demodulates a signal on the IQ plane, that is, a complex signal. The complex signal is input to the time de-interleave unit 27, and the signal spread in time is returned to the original arrangement. At this time, the mixed pulse disturbance is dispersed in time. After that, IQ de-mapping is performed by the carrier demodulating unit 28 and the digital data (bit data) is restored, and then the error correction decoding unit 29 corrects the error. The signal subjected to error correction decoding is reproduced as an audio signal through the information source decoding unit 25.

Radio equipment standard for specific radio microphones on land mobile stations (ARIB STD-T112 1.3 version), Japan Radio Industry Association

  For OFDM digital wireless microphones, a standard (Non-Patent Document 1) is established and time interleaving is adopted, but in reality, pulse noise cannot be removed sufficiently and pulse interference occurs. There was no product available in the environment. In the conventional system, in the error correction processing after time de-interleaving, the data subjected to pulse interference (noise) is erroneously recognized and processed as reliable data, and proper error correction cannot be performed. This is one reason.

  In addition, for single-carrier wireless microphones, products that partially support pulsed interference have been announced, but sufficient measures against various pulse interferences have not yet been established.

  Accordingly, an object of the present invention made in view of the above problems is to provide a digital wireless microphone that can be used even in an environment with pulse interference, particularly an interference-resistant digital wireless microphone of the OFDM modulation / demodulation method.

  In order to solve the above problems, a digital wireless microphone receiver according to the present invention includes a complex signal demodulator that demodulates a complex signal from a received signal, a time de-interleave unit, a carrier demodulator, and an error correction decoder. In the digital wireless microphone receiver having at least an information source decoding unit, an erasure interval determination unit that determines an interval in which the received signal is disturbed by pulse noise is provided, and the determination result of the erasure interval determination unit On the basis of this, it is characterized in that error correction decoding is performed after performing erasure processing in which the signal data in the section subjected to the interference is zero.

  In order to solve the above problems, a digital wireless microphone receiver according to the present invention includes a complex signal demodulator that demodulates a complex signal from a received signal, and an erasure section that determines a section in which the received signal is disturbed by pulse noise. In the digital wireless microphone receiver including at least a determination unit, a time de-interleave unit, a carrier demodulation unit, an error correction decoding unit, and an information source decoding unit, the erasure section determination unit includes the complex signal When the absolute value (| S |) of the signal obtained from the demodulator is equal to or greater than a predetermined threshold (Wth), it is determined that the received signal has been disturbed by pulse noise, and the interference has been received. It is characterized in that error correction is performed after erasure processing is performed in which the signal data in the section is zero.

  In the digital wireless microphone receiver, the erasure interval determination unit includes a signal absolute value calculation unit that derives an absolute value (| S |) of a signal obtained from the complex signal demodulation unit, and the signal absolute value The determination result signal (P) is 1 when the absolute value (| S |) derived by the arithmetic unit is less than the threshold value (Wth), and 0 when the absolute value (| S |) is greater than or equal to the threshold value (Wth). An output signal absolute value determination unit is provided, and it is preferable to perform error correction after performing the process of multiplying the determination result signal (P) by the signal data of the corresponding section.

  In order to solve the above problems, a digital wireless microphone receiver according to the present invention includes a complex signal demodulator that demodulates a complex signal from a received signal, and an erasure section that determines a section in which the received signal is disturbed by pulse noise. In the digital wireless microphone receiver including at least a determination unit, a time de-interleave unit, a carrier demodulation unit, an error correction decoding unit, and an information source decoding unit, the erasure section determination unit includes the complex signal When the modulation error (ME) of the signal obtained from the demodulator is equal to or greater than a predetermined threshold (MEth), it is determined that the received signal has been disturbed by pulse noise. It is characterized in that error correction is performed after erasure processing is performed in which the signal data in the interval is zero.

  Further, in the digital wireless microphone receiver, the erasure interval determination unit includes an ME operation unit that calculates a modulation error (ME) of the signal obtained from the complex signal demodulation unit, and the ME operation unit. ME determination unit that outputs a determination result signal (P) that is 1 when the calculated modulation error (ME) is less than the threshold value (MEth) and that is 0 when the modulation error (ME) is equal to or greater than the threshold value (MEth). It is preferable to perform error correction after performing the process of multiplying the determination result signal (P) by the signal data of the corresponding section.

  In order to solve the above problems, a digital wireless microphone receiver according to the present invention includes a complex signal demodulator that demodulates a complex signal from a received signal, and an erasure section that determines a section in which the received signal is disturbed by pulse noise. In the digital wireless microphone receiver including at least a determination unit, a time de-interleave unit, a carrier demodulation unit, an error correction decoding unit, and an information source decoding unit, the erasure section determination unit includes the complex signal Based on the absolute value (| S |) of the signal obtained from the demodulator and the modulation error (ME) of the signal obtained from the complex signal demodulator, the received signal is disturbed by pulse noise. The received section is determined, and error correction is performed after erasure processing is performed in which the signal data of the section subjected to the interference is zero.

  In order to solve the above problems, a digital wireless microphone receiver according to the present invention determines an OFDM complex signal demodulator that demodulates a complex signal from an OFDM received signal, and a section in which the OFDM received signal is disturbed by pulse noise. An erasure interval determination unit, a time de-interleaving unit, a carrier demodulation unit, an error correction decoding unit, and an information source decoding unit, wherein the erasure interval determination unit includes: When the absolute value (| CSI |) of the transmission path information is equal to or greater than a predetermined threshold (Wth), it is determined that the OFDM reception signal is disturbed by pulse noise, and the signal of the section subjected to the interference It is characterized in that error correction is performed after performing erasure processing with zero data.

  Further, in the digital wireless microphone receiver, the erasure interval determination unit includes a CSI absolute value calculation unit that calculates an absolute value (| CSI |) of the transmission path information and an absolute value calculated by the CSI absolute value calculation unit. CSI absolute value determination that outputs a determination result signal (P), which is 1 when the value (| CSI |) is less than the threshold value (Wth) and 0 when the value (| CSI |) is greater than or equal to the threshold value (Wth). It is preferable to perform error correction after performing a process of multiplying the determination result signal (P) by the signal data of the corresponding section.

  In order to solve the above problems, a digital wireless microphone receiver according to the present invention determines an OFDM complex signal demodulator that demodulates a complex signal from an OFDM received signal, and a section in which the OFDM received signal is disturbed by pulse noise. An erasure interval determination unit, a time de-interleaving unit, a carrier demodulation unit, an error correction decoding unit, and an information source decoding unit, wherein the erasure interval determination unit includes: When the modulation error (ME: Modulation Error) of the signal obtained from the OFDM complex signal demodulator is equal to or greater than a predetermined threshold (MEth), it is determined that the received signal is disturbed by pulse noise, It is characterized in that error correction is performed after performing erasure processing for setting the signal data in the section subjected to the interference to zero.

  In the digital wireless microphone receiving apparatus, the erasure interval determination unit includes a ME operation unit that calculates a modulation error (ME) of the signal obtained from the OFDM complex signal demodulation unit, and the ME operation unit. ME that outputs a determination result signal (P) is 1 when the modulation error (ME) calculated by (1) is less than the threshold (MEth), and 0 when it is greater than or equal to the threshold (MEth). It is preferable to perform error correction after performing a process of multiplying the determination result signal (P) by the signal data of the corresponding section.

  In order to solve the above problems, a digital wireless microphone receiver according to the present invention determines an OFDM complex signal demodulator that demodulates a complex signal from an OFDM received signal, and a section in which the OFDM received signal is disturbed by pulse noise. An erasure interval determination unit, a time de-interleaving unit, a carrier demodulation unit, an error correction decoding unit, and an information source decoding unit, wherein the erasure interval determination unit includes: Section in which the received signal is disturbed by pulse noise based on the absolute value (| CSI |) of transmission path information and the modulation error (ME) of the signal obtained from the OFDM complex signal demodulator And error correction is performed after erasure processing is performed in which the signal data in the section subjected to the interference is zero.

  In the digital wireless microphone receiver, the erasure interval determination unit is 1 when the OFDM reception signal is not disturbed by pulse noise, and the interval where the OFDM reception signal is disturbed by pulse noise is 1 A determination result signal (P) that is 0 is output, and the determination result signal (P) is multiplied by the absolute value (| CSI |) of the transmission path information and the signal data of the corresponding section. It is desirable to perform error correction soft decision decoding later.

  In the digital wireless microphone receiving apparatus, it is preferable that reception is performed by a diversity method, and in the diversity combining type, norm calculation is used as an absolute value (| CSI |) of transmission path information of each branch.

  According to the present invention, it is possible to provide a digital wireless microphone that can be used stably even when pulse interference occurs.

It is a block diagram which shows the basic composition of the receiver for digital wireless microphones by this invention. It is a block diagram which shows the modification of the receiver for digital wireless microphones by this invention. It is a block diagram which shows the receiver for digital wireless microphones of Example 1 (absolute value determination of a received signal). It is a block diagram which shows the receiver for digital wireless microphones of Example 2 (noise determination). It is a block diagram which shows the receiver for digital wireless microphones of Example 3 (determination of a received signal absolute value and noise). It is a block diagram which shows the structure of the transmission-line decoding part of Example 4 (CSI absolute value determination). It is a block diagram which shows the structure of the transmission-line decoding part of Example 5 (noise determination). It is a block diagram which shows the structure of the transmission-line decoding part of Example 6 (CSI absolute value and noise determination). It is a block diagram which shows the structure of the transmission-line decoding part of Example 7 (CSI weighting soft decision). It is a block diagram which shows the structure of the transmission-line decoding part to which receiving diversity is applied. It is a block diagram which shows the structural example of a diversity synthetic | combination part. It is a block diagram which shows the basic composition of an OFDM digital wireless microphone. It is a block diagram which shows the structure of the transmission-line encoding part of an OFDM digital wireless microphone. It is a block diagram which shows the structure of the transmission-line decoding part of an OFDM digital wireless microphone. It is a figure explaining the interference by pulse noise. It is a figure explaining the effect | action of time interleaving. It is a block diagram which shows the transmission / reception apparatus of a digital wireless microphone.

  Embodiments of the present invention will be described below.

  FIG. 1 is a block diagram showing a basic configuration of a digital wireless microphone receiver of the present invention. Note that the same components as those of the conventional digital wireless microphone receiver illustrated in FIG. 17B are denoted by the same reference numerals, and description thereof is simplified.

  The receiving apparatus of the present invention receives a signal interleaved on the transmission side, and a transmitting apparatus 11 of a conventional digital wireless microphone shown in FIG. 17A can be used as the transmitting apparatus.

  The receiving apparatus includes a receiving antenna, a receiving amplifying unit 22, a complex signal demodulating unit 26, a time de-interleaving unit 27, a carrier demodulating unit 28, an error correction decoding unit 29, an information source, and a conventional configuration. In addition to the decoding unit 25, a lost section determining unit 80 and a mechanism 81 for performing a section lost process are included.

  A signal from the reception antenna is amplified by the reception amplification unit 22 and input to the complex signal demodulation unit 26. The complex signal demodulator 26 demodulates the complex signal S (IQ signal) from the received signal. The complex signal S is input to the time de-interleave unit 27.

  The time de-interleaving unit 27 restores the signal that has been temporally spread by the time interleaving on the transmission side to the original arrangement by the opposite process. At this time, the signal arrangement is restored, and the signal subjected to the pulse disturbance is dispersed in time.

  The erasure section determination unit 80 determines a section in which data reliability is lost due to pulse interference. The pulse noise has a very large amplitude, and a signal such as an interference undergoes alteration such as noise including noise. The erasure section determination unit 80 estimates the section that has received the pulse interference using the property of the modified complex signal.

  The mechanism 81 that performs the interval erasure process causes the signal in the interval estimated by the erasure interval determination unit 80 among the signals output from the time de-interleave unit 27 to disappear (zero insertion). In the figure, the mechanism 81 that performs the interval erasure processing shows a configuration in which the signal from the time de-interleave unit 27 and the zero (0) signal are switched based on the output from the erasure interval determination unit 80. However, any electronic processing may be used as long as the signal that has received interference (disturbance) is lost.

  Thereafter, the same processing as that of the conventional receiving apparatus is performed. That is, the complex signal is de-mapped by the carrier demodulator 28 and returned to digital data (bit data), and then the error correction decoder 29 corrects the error. Note that the carrier demodulation unit 28 may be disposed before the section erasure processing mechanism 81 to perform the erasure processing in the section subjected to pulse interference on the de-mapped digital data. In both processes, error correction functions effectively by performing error correction decoding after performing erasure processing of a section subjected to pulse interference.

  The signal subjected to error correction decoding is reproduced as an audio signal through the information source decoding unit 25.

  The digital wireless microphone receiving apparatus of the present invention eliminates interference (disturbance) signals and generates zero (0) signals. Therefore, the error correction processing in the error correction decoding unit 29 has received interference (disturbance). No signal is used, and data can be restored by appropriate error correction. Thereby, it is possible to realize a digital wireless microphone system in which the quality of an audio signal is not deteriorated even when pulse interference is received.

  The basic configuration of the present invention shown in FIG. 1 is advantageous in terms of hardware because there is no overlapping structure because data that has undergone pulse interference and data that has not been received are processed by the common time de-interleaving unit 27. .

  FIG. 2 is a block diagram in which the configuration of the digital wireless microphone receiver of FIG. 1 is modified. The difference from the configuration of FIG. 1 is that the position of the disappearance section determination unit 80 is set in front of the time de-interleave units 271 and 272.

  As shown in FIG. 2, in the modified example of the receiving apparatus of the present invention, the signal from the receiving antenna is amplified by the receiving amplifier 22, and the complex signal S (IQ signal) is demodulated from the received signal by the complex signal demodulator 26. . Thereafter, the complex signal S is input to the time de-interleave unit 271 and also input to the erasure interval determination unit 80.

  The time de-interleaving unit 271 restores the signal that has been temporally spread by the time interleaving on the transmission side to the original arrangement by the opposite process.

  The erasure interval determination unit 80 determines an interval in which data reliability has been lost due to pulse interference with respect to a signal before time deinterleaving. The erasure interval determination unit 80 estimates the interval subjected to the pulse interference using the property of the complex signal altered by the pulse interference, and outputs the result to the time de-interleaving unit 272.

  The time de-interleaving unit 272 performs a process equivalent to the process of returning the temporally spread signal to the original arrangement on the output of the erasure interval determination unit 80, and de-interleaves the information of the erasure interval The result is output to the mechanism 81 for performing the section disappearance process.

  The mechanism 81 that performs the interval erasure process is based on the signal obtained by performing the time de-interleave processing on the output of the erasure interval determination unit 80, and the signal (interval signal) that is disturbed among the signals from the time de-interleave unit 271. Disappear (zero insertion). The mechanism 81 for performing the section disappearance process may be realized by any electronic process as long as it is a process for erasing a signal that has received interference (disturbance).

  Thereafter, the same processing as that of the conventional receiving apparatus is performed. That is, the complex signal is de-mapped by the carrier demodulator 28 and returned to digital data (bit data), and then the error correction decoder 29 corrects the error. Note that the carrier demodulation unit 28 may be disposed before the section erasure processing mechanism 81 to perform the erasure processing in the section subjected to pulse interference on the de-mapped digital data. In both processes, error correction functions effectively by performing error correction decoding after performing erasure processing of a section subjected to pulse interference.

  The signal subjected to error correction decoding is reproduced as an audio signal through the information source decoding unit 25.

  The digital wireless microphone receiver of this modification is also the same in principle as the receiver of FIG. 1 and eliminates the signal that has been interfered (disturbed), resulting in a zero (0) signal. In the error correction processing at 29, data can be restored by appropriate error correction. In this case, two time de-interleaving units 271 and 272 for the main line signal and the output signal of the disappearance interval determination unit 80 are required. On the other hand, this configuration is performed before performing the time de-interleaving for the determination of the pulse interference. In order to process, the signal which received the pulse disturbance is gathered, and there exists the characteristic that determination of an erasure | elimination area (estimation of a pulse width) becomes easy.

  FIG. 3 is a block diagram showing a digital wireless microphone receiver as a first embodiment of the present invention. In the receiving apparatus according to the first embodiment, the absolute value calculation is performed to detect the amplitude of the signal (complex signal) S, and the value of the amplitude (| S |) of the complex signal S is compared with the threshold value Wth. Judgment is made.

  The configuration of the receiver for the digital wireless microphone of Embodiment 1 in FIG. 3 has substantially the same configuration as the basic configuration of the receiver in FIG. 1, and includes a reception antenna, a reception amplification unit 22, and complex signal demodulation. Unit 26, time de-interleave unit 27, erasure interval determination unit 80, multiplier 84, carrier demodulation unit 28, error correction decoding unit 29, and information source decoding unit 25. The function of each component is the same as in FIG.

  The erasure section determination unit 80 includes a signal absolute value calculation unit 82 and a signal absolute value determination unit 83, and the signal absolute value calculation unit 82 applies the complex signal S output from the time de-interleave unit 27 to the complex signal S. The absolute value (| S |) of the complex signal S indicating the amplitude is derived.

  Note that the absolute value (| S |) of the complex signal S can be calculated and obtained, and since it is the amplitude of the received signal, an RSSI (Received Signal Strength Indication) signal or AGC (Automatic) output from the high frequency tuner. Gain Control) voltage can also be used. The signal absolute value calculation unit 82 may obtain the absolute value (| S |) using any means.

  The signal absolute value determination unit 83 compares the amplitude value (| S |) of the complex signal S derived by the signal absolute value calculation unit 82 with the threshold value Wth. A signal that has received interference (disturbance) due to strong pulse noise is altered, and when demodulated, its amplitude shows a large abnormal value. In the first embodiment, signal alteration due to this interference is used, and when the signal level of the output of the signal absolute value calculation unit 82 (amplitude | S | of the complex signal S) is lower than the threshold value Wth, reliability is improved. When the signal level of the amplitude | S | is equal to or greater than the threshold value Wth, 0 is set as an output of the signal absolute value determination unit 83.

  Therefore, the erasure section determination unit 80 outputs a determination result signal P of 1 for the signal S determined not to be subjected to pulse interference and 0 for the signal S determined to have received pulse interference.

  The multiplier 84 multiplies the complex signal S output from the time de-interleave unit 27 and the signal P (1 or 0) from the erasure interval determination unit 80, and as a result, determines the signal that has been subjected to pulse interference. S becomes zero (0) and disappears.

  Although not shown in the figure, it is desirable to provide a delay adjustment means for adjusting the time required for the processing of the erasure interval determination unit 80 between the time de-interleave unit 27 and the multiplier 84.

  After erasure processing is performed by the erasure interval determination unit 80 and the multiplier 84 to make the interval where the received signal is disturbed by pulse noise zero, de-mapping by the carrier demodulation unit 28 and error correction by the error correction decoding unit are performed. Do. The carrier demodulating unit 28 may be provided before the multiplier 84, and the erasure period that has been subjected to the pulse interference can be eliminated for the bit data after the demapping.

  The first embodiment can be applied to both a single-carrier digital wireless microphone and an OFDM modulation / demodulation digital wireless microphone. Erasure processing is performed based on the amplitude of the demodulated signal (complex signal) S, and a high-quality sound output can be obtained relatively easily.

  Although the first embodiment has a structure based on the basic configuration of the receiving apparatus in FIG. 1, a structure based on a modification of the receiving apparatus in FIG. 2 may be adopted.

  FIG. 4 is a block diagram showing a digital wireless microphone receiver as a second embodiment of the present invention. In the receiving apparatus according to the second embodiment, calculation is performed to detect an error amount (ME: Modulation Error) of the signal (complex signal) S, and the value of the error amount (ME) is compared with a threshold value MEth to disappear. Determine the section.

ME (Modulation Error) is to perform the following calculation.
ME = | received signal S−estimated value of received signal <S> |
Here, the estimated value <S> of the received signal is a signal obtained by determining the received signal S by region determination or the like on the complex plane.

  The configuration of the receiver for the digital wireless microphone of the second embodiment in FIG. 4 has substantially the same configuration as the basic configuration of the receiver in FIG. 1, and includes a reception antenna, a reception amplification unit 22, and a complex signal demodulation. Unit 26, time de-interleave unit 27, erasure interval determination unit 80, multiplier 84, carrier demodulation unit 28, error correction decoding unit 29, and information source decoding unit 25. The function of each component is the same as in FIG.

  Erasure interval determination unit 80 includes an ME calculation unit 85 and an ME determination unit 86. ME calculation unit 85 estimates an error amount of complex signal S output from time de-interleaving unit 27. (ME) is calculated.

  The ME determination unit 86 compares the error amount (ME) of the received signal (complex signal) S calculated by the ME calculation unit 85 with the threshold value MEth. A signal subjected to interference (disturbance) due to strong pulse noise shows an abnormal value with a large error amount. In the second embodiment, when the signal error amount due to the interference is used and the signal level of the output (ME) of the ME calculation unit 85 is lower than the threshold value MEth, 1 is determined as a reliable signal, When the signal level of the output (ME) is equal to or higher than the threshold value MEth, 0 is set as the output of the ME determination unit 86 because the signal is subjected to pulse interference.

  Therefore, the erasure section determination unit 80 outputs a determination result signal P of 1 for the signal S determined not to be subjected to pulse interference and 0 for the signal S determined to have received pulse interference.

  The multiplier 84 multiplies the complex signal S output from the time de-interleave unit 27 and the signal P (1 or 0) from the erasure interval determination unit 80, and as a result, determines the signal that has been subjected to pulse interference. S becomes zero (0) and disappears.

  Although not shown in the figure, it is desirable to provide a delay adjustment means for adjusting the time required for the processing of the erasure interval determination unit 80 between the time de-interleave unit 27 and the multiplier 84.

  After erasure processing is performed by the erasure interval determination unit 80 and the multiplier 84 to make the interval where the received signal is disturbed by pulse noise zero, de-mapping by the carrier demodulation unit 28 and error correction by the error correction decoding unit are performed. Do. The carrier demodulating unit 28 may be provided before the multiplier 84, and the erasure period that has been subjected to the pulse interference can be eliminated for the bit data after the demapping.

  In the second embodiment, the error amount (ME) is used, but MER (Modulation Error Ratio) may be used for the disappearance section determination unit. When the MER is used, the MER value is compared with the threshold value MERth. When the MER is large, 1 is output as a signal not subjected to pulse interference, and when the MER is small, the signal subjected to pulse interference. Is output as 0.

  The second embodiment can be applied to both a single-carrier digital wireless microphone and an OFDM modulation / demodulation digital wireless microphone. Erasure processing is performed based on the error amount (ME) of the demodulated signal (complex signal) S, and a high-quality voice output can be obtained relatively easily.

  Although the second embodiment has a structure based on the basic configuration of the receiving apparatus in FIG. 1, a structure based on a modification of the receiving apparatus in FIG. 2 may be adopted.

  FIG. 5 is a block diagram showing a digital wireless microphone receiver as a third embodiment of the present invention. In the receiving apparatus according to the third embodiment, the interval (disappearance interval) in which the pulse interference is received is estimated using both the amplitude (| S |) and the error amount (ME) of the signal (complex signal) S.

  The configuration of the digital wireless microphone receiver of the third embodiment of FIG. 5 includes substantially the same configuration as the modification of the basic configuration of the receiver of FIG. 2, and includes a reception antenna, a reception amplification unit 22, Complex signal demodulator 26, time de-interleaver 271, erasure interval determiner 80, time de-interleaver 272, multiplier 84, carrier demodulator 28, error correction decoder 29, information source A decoding unit 25 is included. The function of each component is the same as in FIG.

  Erasure interval determination unit 80 includes a signal absolute value calculation unit 82, a ME calculation unit 85, and a pulse interval estimation unit 87. The signal absolute value calculation unit 82 derives the absolute value (| S |) of the complex signal S indicating the amplitude of the complex signal S output from the complex signal demodulation unit 26. Note that, in derivation of the absolute value (| S |), it may be obtained by calculation, or an RSSI signal or an AGC voltage may be used as in the first embodiment.

  The ME calculation unit 85 calculates an estimated value (ME) of the error amount for the complex signal S output from the complex signal demodulation unit 26.

  The pulse interval estimation unit 87 compares the amplitude value (| S |) of the complex signal S calculated by the signal absolute value calculation unit 82 with the threshold value Wth, and receives the received signal (complex signal calculated by the ME calculation unit 85). ) The error amount (ME) of S is compared with the threshold value MEth. In the third embodiment, the determination based on the amplitude | S | of the complex signal S (1 when the amplitude | S | is lower than the threshold value Wth, 0 when the amplitude | S | is equal to or higher than the threshold value Wth) and the received signal (complex). Signal) judgment based on the error amount (ME) of S (1 if the error amount (ME) is less than the threshold value MEth, 0 if it is greater than or equal to the threshold value MEth), and the pulse interval estimation unit 87 Determine the output of.

  For example, the output of the pulse section determination unit 87 is determined by AND operation or OR operation of the determination result based on the amplitude | S | of the complex signal S and the determination result based on the error amount (ME). According to the AND operation, a signal that is suspected of being disturbed by a pulse is removed, and if it is an OR operation, the determination of the pulse interference is eased. Furthermore, it is also possible to make a determination by weighting both determination results.

  As a result, the erasure section determination unit 80 outputs a determination result signal P of 1 for the signal S determined not to be subjected to pulse interference and 0 for the signal S determined to have received pulse interference.

  The output of the disappearance section determination unit 80 is then subjected to processing for returning to the original arrangement in the time de-interleaving unit 272.

  The multiplier 84 multiplies the complex signal S output from the time de-interleave unit 271 by the signal P (1 or 0) from the time de-interleave unit 272, and as a result, determines that the pulse interference has been received. The signal S becomes zero (0) and disappears.

  Although not shown in the figure, a delay adjustment means is provided between the time de-interleave unit 271 and the multiplier 84 to adjust the time required for the processing of the erasure interval determination unit 80 and the time de-interleave unit 272. It is desirable.

  The multiplier 84 performs an erasure process in which the interval in which the received signal is disturbed by pulse noise is zero, and then performs de-mapping by the carrier demodulator 28 and error correction by the error correction decoder. The carrier demodulating unit 28 may be provided before the multiplier 84, and the erasure period that has been subjected to the pulse interference can be eliminated for the bit data after the demapping.

  The third embodiment can be applied to both a single carrier digital wireless microphone and an OFDM modulation / demodulation digital wireless microphone. It is possible to perform erasure processing based on both the amplitude of the demodulated signal (complex signal) S and the error amount (ME), and perform more precise determination to obtain a high-quality sound output.

  In addition, although Example 3 has a structure based on the modification of the receiving apparatus of FIG. 2, you may employ | adopt the structure based on the basic composition of the receiving apparatus of FIG.

  Next, the case where the present invention is applied to an OFDM digital transmission type wireless microphone will be described. The basic configuration of the OFDM digital wireless microphone is as described with reference to FIG. 12, and the configuration of the transmission path decoding unit 24 on the receiving side will be described in detail below.

  FIG. 6 is a block diagram showing a transmission path decoding unit of a digital wireless microphone receiver as a fourth embodiment of the present invention. The transmission path decoding unit according to the present embodiment performs determination of a section (erasure section) that has received pulse interference using an absolute value of transmission path information (CSI: Channel State Information).

  The configuration of the transmission path decoding unit of the receiving apparatus of the fourth embodiment in FIG. 6 includes a basic configuration of the transmission path decoding unit in FIG. 14 plus an erasure interval determination unit 80, and includes a window processing unit 51, An FFT (Fast Fourier Transform) unit 52, an OFDM frame demultiplexing unit 53, an interpolation filter unit 54, a complex division unit 55, an erasure interval determination unit 80, a time de-interleaving unit 56, a frequency de-interleaving unit 56, An interleaving unit 57, a carrier demodulating unit 58, a multiplier 91, an error correction decoding unit 61, and an energy despreading unit 62 are included. The function of each component is the same as in FIG.

  In the present invention, a window processing unit 51, an FFT (Fast Fourier Transform) unit 52, an OFDM frame de-multiplexing unit 53, an interpolation filter unit 54, and a complex division unit 55 are used, A block group that outputs a complex signal (Data) and transmission path information (CSI) may be referred to as an “OFDM complex signal demodulator”.

  The disappearance section determination unit 80 includes a CSI absolute value calculation unit 88 and a CSI absolute value determination unit 89.

  In the interpolation filter unit 54, transmission path information (CSI) corresponding to all carrier symbols is obtained from the extracted pilot signal, and the CSI absolute value calculation unit 88 calculates an absolute value (| CSI |) indicating the amplitude of this CSI. ) Is calculated. As will be described later, the absolute value of the CSI may be obtained for every carrier symbol or may be obtained for each symbol. The CSI absolute value determination unit 89 determines the disappearance section by comparing the absolute value of CSI (| CSI |) with the threshold value Wth.

  If there is interference (disturbance) due to strong pulse noise, the CSI is affected and the amplitude shows a large abnormal value. In the fourth embodiment, it is assumed that a reliable symbol is transmitted when the signal level of the output (| CSI |) of the CSI absolute value calculation unit 88 is lower than the threshold value Wth using the influence of this interference. When the signal level of the output (| CSI |) is equal to or higher than the threshold value Wth, 0 is set as the output of the CSI absolute value determination unit 89, assuming that the symbol subjected to pulse interference is transmitted.

  Therefore, the erasure section determination unit 80 outputs a determination result signal P of 1 for a section determined not to be subjected to pulse interference and 0 for a section determined to have received pulse interference.

  The determination result signal (information of the determined disappearance interval) is de-interleaved by the time de-interleaving unit 56 and the frequency de-interleaving unit 57, respectively. Similarly, the demodulated main line data is multiplied by a multiplier 91 and subjected to erasure processing, and then input to an error correction decoding unit 61 to perform error correction such as Viterbi decoding. Thereafter, normal OFDM signal decoding processing is performed.

  The determination of the erasure period can be performed for each carrier symbol of the OFDM signal, or can be performed for each OFDM signal symbol unit (a group of carrier symbols transmitted at the same timing). If the OFDM symbol number is i and the carrier number is k, the transmission path information CSI can be described as CSI (i, k). When determining an erasure section for each carrier symbol, the determination is performed in units of CSI (i, k).

  On the other hand, when the calculation is performed in symbol units, the arithmetic mean calculation is performed in the carrier direction. Assuming that the number of OFDM subcarriers is K, transmission path information CSI in symbol units is obtained by the following equation.

  Using this symbol unit value, the absolute value of the transmission path information CSI is compared with the threshold value Wth for each symbol to determine the erasure interval.

  In the fourth embodiment, the demodulated main line data (Data) and the determination result signal P of the erasure section determination unit 80 are obtained, and then time deinterleaving is performed. Although it has a structure based on an example, a structure based on the basic configuration of the receiving apparatus in FIG. 1 may be adopted.

  In FIG. 6, the multiplier 91 is disposed after the carrier demodulator 58, but the multiplier 91 is disposed between the frequency de-interleave unit 57 and the carrier demodulator 58, and the complex signal S is By multiplying the determination result signal P, the signal that has received the pulse interference may be lost.

  FIG. 7 is a block diagram illustrating a transmission path decoding unit of a digital wireless microphone receiver as a fifth embodiment of the present invention. The transmission path decoding unit according to the present embodiment performs determination of a section (erasure section) that has received pulse interference using an error amount (ME: Modulation Error) of a signal (Data, complex signal S). Here, the ME (Modulation Error) defined in the second embodiment may be used as the error amount (ME).

  The configuration of the transmission path decoding unit of the receiving apparatus of the fifth embodiment in FIG. 7 includes a basic configuration of the transmission path decoding unit in FIG. 14 plus an erasure interval determination unit 80, and includes a window processing unit 51, An FFT (Fast Fourier Transform) unit 52, an OFDM frame demultiplexing unit 53, an interpolation filter unit 54, a complex division unit 55, an erasure interval determination unit 80, a time de-interleaving unit 56, a frequency de-interleaving unit 56, An interleaving unit 57, a carrier demodulating unit 58, a multiplier 91, an error correction decoding unit 61, and an energy despreading unit 62 are included. The function of each component is the same as in FIG.

  Vanishing section determination unit 80 includes an ME calculation unit 85 and an ME determination unit 86.

  In the interpolation filter unit 54, transmission path information (CSI) corresponding to all carrier symbols is obtained from the extracted pilot signal, and detection processing of all carrier symbols is performed by complex-dividing the main line data signal by CSI. Done. The ME calculation unit 85 calculates a modulation error amount (ME) from the detected signal. As will be described later, this modulation error amount (ME) may be obtained for every carrier symbol or may be obtained for each symbol. The ME determination unit 86 compares the ME value with the threshold value MEth to determine the disappearance section.

  As in the second embodiment, if there is a pulse interference, the modulation error (ME) increases. Therefore, the influence of this interference is used, and the signal level of the output (ME) of the ME computing unit 85 falls below the threshold value MEth. Is 1 as a reliable signal, and when the signal level of the output (ME) is equal to or higher than the threshold value MEth, 0 is assumed as a signal subjected to pulse interference, and the output of the ME determination unit 86 To do.

  Therefore, the erasure section determination unit 80 outputs a determination result signal P of 1 for the signal S determined not to be subjected to pulse interference and 0 for the signal S determined to have received pulse interference.

  The determination result signal (information of the determined disappearance interval) is de-interleaved by the time de-interleaving unit 56 and the frequency de-interleaving unit 57, respectively. Similarly, the demodulated main line data is multiplied by a multiplier 91 and subjected to erasure processing, and then input to an error correction decoding unit 61 to perform error correction such as Viterbi decoding. Thereafter, normal OFDM signal decoding processing is performed.

  The determination of the erasure period can be performed for each carrier symbol of the OFDM signal, or can be performed for each symbol of the OFDM signal. If the OFDM symbol number is i and the carrier number is k, the modulation error ME can be described as ME (i, k). When determining an erasure section for each carrier symbol, the determination is performed in units of ME (i, k).

  On the other hand, when the calculation is performed in symbol units, the arithmetic mean calculation is performed in the carrier direction. When the number of OFDM subcarriers is K, an error amount ME in symbol units is obtained by the following equation.

  Using this value in symbol units, the error amount ME (i) is compared with the threshold value MEth for each symbol to determine the erasure interval.

  In the fifth embodiment, since the demodulated main line data (Data) and the determination result signal P of the erasure section determination unit 80 are obtained, time deinterleaving is performed, respectively. Although it has a structure based on an example, a structure based on the basic configuration of the receiving apparatus in FIG. 1 may be adopted.

  In FIG. 7, the multiplier 91 is arranged after the carrier demodulating unit 58, but the multiplier 91 is arranged between the frequency de-interleaving unit 57 and the carrier demodulating unit 58, and the complex signal S is By multiplying the determination result signal P, the signal that has received the pulse interference may be lost.

  FIG. 8 is a block diagram showing a transmission path decoding unit of a digital wireless microphone receiving apparatus as a specific embodiment 6 of the present invention. The transmission path decoding unit according to the present embodiment uses the absolute value of the transmission path information (CSI) and the error amount (ME: Modulation Error) of the signal (Data, complex signal S) to receive the pulse interference. (Erasure interval) is determined.

  The configuration of the transmission path decoding unit of the receiving apparatus of the sixth embodiment in FIG. 8 includes a basic configuration of the transmission path decoding unit in FIG. 14 plus an erasure interval determination unit 80, and includes a window processing unit 51, An FFT (Fast Fourier Transform) unit 52, an OFDM frame demultiplexing unit 53, an interpolation filter unit 54, a complex division unit 55, an erasure interval determination unit 80, a time de-interleaving unit 56, a frequency de-interleaving unit 56, An interleaving unit 57, a carrier demodulating unit 58, a multiplier 91, an error correction decoding unit 61, and an energy despreading unit 62 are included. The function of each component is the same as in FIG.

  The disappearing section determination unit 80 includes an ME calculation unit 85, a CSI absolute value calculation unit 88, and an integration determination unit 90.

  The ME calculation unit 85 calculates a modulation error amount (ME) from a signal (Data, complex signal S) subjected to detection processing by performing complex division on the main line data signal by CSI. This process is the same as in the fifth embodiment.

  Further, the CSI absolute value calculation unit 88 calculates an absolute value (| CSI |) indicating the amplitude of this CSI. This process is the same as in the fourth embodiment.

  The integrated determination unit 90 compares the CSI absolute value (| CSI |) calculated by the CSI absolute value calculation unit 88 with the threshold value Wth, and the error amount of the received signal (complex signal) calculated by the ME calculation unit 85 (ME) is compared with a threshold value MEth. Then, the determination based on the absolute value (| CSI |) indicating the amplitude of CSI and the determination based on the error amount (ME) of the received signal (complex signal) are combined to determine the output of the integrated determination unit 90.

  For example, the output of the integrated determination unit 90 is determined by AND operation or OR operation of the determination result based on the absolute value of CSI (| CSI |) and the determination result based on the error amount (ME). Furthermore, it is also possible to make a determination by weighting both determination results.

  As a result, the erasure section determination unit 80 outputs a determination result signal P of 1 for a section determined not to be subjected to pulse interference and 0 for a section determined to have received pulse interference.

  The determination result signal (information of the determined disappearance interval) is de-interleaved by the time de-interleaving unit 56 and the frequency de-interleaving unit 57, respectively. Similarly, the demodulated main line data is multiplied by a multiplier 91 and subjected to erasure processing, and then input to an error correction decoding unit 61 to perform error correction such as Viterbi decoding. Thereafter, normal OFDM signal decoding processing is performed.

  Note that the erasure period can be determined for each carrier symbol of the OFDM signal, or can be performed for each OFDM signal symbol, as in the fourth and fifth embodiments.

  In the sixth embodiment, the demodulated main line data (Data) and the determination result signal P of the erasure section determination unit 80 are obtained, and then time deinterleaving is performed. Although it has a structure based on an example, a structure based on the basic configuration of the receiving apparatus in FIG. 1 may be adopted.

  In FIG. 8, the multiplier 91 is arranged after the carrier demodulating unit 58. However, the multiplier 91 is arranged between the frequency de-interleaving unit 57 and the carrier demodulating unit 58, and the complex signal S is By multiplying the determination result signal P, the signal that has received the pulse interference may be lost.

  FIG. 9 is a block diagram showing a transmission path decoding unit of a digital wireless microphone receiving apparatus as a seventh embodiment of the present invention. The transmission path decoding unit according to the present embodiment performs determination of a section (erasure section) that has been subjected to pulse interference, and uses the absolute value of transmission path information (CSI) to perform soft decision decoding for error correction of the transmission path decoding unit. Is used.

  The configuration of the transmission path decoding unit of the receiving apparatus of the seventh embodiment in FIG. 9 is the addition of the erasure section determination unit 80 to the basic configuration of the transmission path decoding unit in FIG. 14, and the error correction decoding unit 61 is changed to the error correction soft decision decoding unit. 93, a window processing unit 51, an FFT (Fast Fourier Transform) unit 52, an OFDM frame demultiplexing unit 53, an interpolation filter unit 54, a complex division unit 55, and an erasure interval Determination unit 80, time de-interleave unit 56, frequency de-interleave unit 57, carrier demodulation unit 58, multipliers 91 and 92, error correction soft decision decoding unit 93, energy despreading unit 62, including. Description of functions of the same components as those in FIG. 14 is omitted.

  The erasure section determination unit 80 receives the transmission path information (CSI) obtained by the interpolation filter unit 54 and the data signal (Data) detected by performing complex division on the main line data signal by the CSI, A determination result signal P, which is 1 for a section determined not to be subjected to pulse interference, and 0 for a section determined to have received pulse interference, and an absolute value (| CSI |) indicating the amplitude of CSI, Output.

  The disappearance section determination unit 80 includes a CSI absolute value calculation unit, but other internal configurations can be arbitrarily set. As a method of obtaining the determination result signal P, for example, any one of the above-described Examples 4 to 6 can be used. This determination method can also be adopted.

  Similar to the output data from the complex division unit 55, a time de-interleaving unit 56 and a frequency de-interleaving unit 57 for both the absolute value of CSI (| CSI |) and the signal P from the erasure interval determination unit. To de-interleave each. Thereafter, multipliers 91 and 92 multiply P × | CSI | by the received signal on the main line after carrier demodulation.

  As a result of this multiplication processing, the signal that has been subjected to the pulse interference by the P signal disappears, and the other signals are weighted by the absolute value (| CSI |) of the transmission information.

  Thereafter, error correction soft decision decoding section 93 performs error correction decoding by soft decision. By performing multiplication (weighting) on the signal after carrier demodulation, the reliability of subcarriers whose amplitude is reduced due to channel fading, etc. is reduced, and soft decision decoding is performed, thereby improving error correction performance. Can be raised.

  With this configuration, it is possible to provide a digital wireless microphone transmission / reception device that can be stably used even in an environment where both fading and pulse interference affect.

  In the seventh embodiment, the demodulated main line data (Data), the absolute value of transmission information (| CSI |), and the determination result signal P of the erasure interval determination unit 80 are obtained, Since interleaving is performed, the structure based on the modification of the receiving apparatus in FIG. 2 is provided, but a structure based on the basic configuration of the receiving apparatus in FIG. 1 may be employed.

  In FIG. 9, the multipliers 91 and 92 are arranged after the carrier demodulating unit 58. However, the multipliers 91 and 92 are arranged between the frequency de-interleaving unit 57 and the carrier demodulating unit 58, and the complex signal The determination result signal P may be multiplied by S to eliminate the signal that has received the pulse interference.

  FIG. 10 is a block diagram illustrating a transmission path decoding unit of a digital wireless microphone receiving apparatus to which reception diversity is applied.

  Receive diversity improves the quality and reliability of communication by preferentially using antenna signals with excellent radio wave conditions or synthesizing received signals for the same radio signal received by multiple antennas. It is a technology that aims to. Although it can be combined with any of the embodiments described so far, FIG. 10 shows an example applied to an embodiment (embodiment 7) of soft decision decoding based on weighting of transmission path information (CSI).

  The configuration of the transmission path decoding unit of the diversity receiver in FIG. 10 is different from the basic configuration of the conventional transmission path decoding unit in FIG. 14 in that it includes a window processing unit 51, an FFT (Fast Fourier Transform) unit 52, an OFDM frame decoder. A plurality of receivers (here, n systems) including a multiplex unit 53 and an interpolation filter unit 54 are provided, and the received signals can be strengthened by receiving OFDM received signals in n systems.

  The OFDM received signals 1 to n received by the n systems are converted into data signals (Data) and transmission path information (CSI), respectively, and input to the diversity combining unit 94. Based on the data signals (Data) 1 to n and transmission path information (CSI) 1 to n of a plurality of systems, the diversity combining unit 94 improves the quality of the data signal Data and the absolute value of the transmission path information (| CSI |) And a determination result signal P, which is a result of determining the disappearance interval, is calculated and output.

  A time de-interleaving unit 56 and a frequency de-interleaving unit are provided for the data signal output from the diversity combining unit 94, the absolute value of CSI (| CSI |), and the signal P from the erasure interval determining unit. In 57, deinterleaving is performed, and multipliers 91 and 92 multiply P × | CSI | by the received signal on the main line after carrier demodulation. In FIG. 10, the multipliers 91 and 92 are arranged after the carrier demodulating unit 58. However, the multipliers 91 and 92 are arranged between the frequency de-interleaving unit 57 and the carrier demodulating unit 58, and the complex signal The determination result signal P may be multiplied by S to eliminate the signal that has received the pulse interference.

  As a result of this multiplication processing, the signal that has been subjected to the pulse interference by the P signal disappears, and the other signals are weighted by the absolute value (| CSI |) of the transmission information.

  Thereafter, error correction soft decision decoding section 93 performs error correction decoding by soft decision. By performing multiplication (weighting) on the carrier demodulated signal, the reliability of subcarriers whose amplitude is reduced due to channel fading, etc. is lowered, and the reliability of subcarriers with large amplitude is increased to make soft decisions. By performing decoding, the performance of error correction can be improved.

  With this configuration, it is possible to provide a digital wireless microphone transmission / reception device that can be stably used even in an environment where both fading and pulse interference affect.

FIG. 11 shows a configuration example of the diversity combining unit 95. Based on the transmission path information (CSI) 1 to n [H _l (k)] of a plurality (n) of systems, diversity combining section 95 uses weighting coefficient W _l (k ) And for each system, the weighting factor W _l (k) is multiplied by each data signal X _l (k) and synthesized by the synthesis unit 97 to derive a data signal Data with improved quality. To do.

Also, the absolute value (| CSI |) of the entire CSI is obtained by using the norm synthesis of CSI obtained from each system (that is, the denominator of the weight coefficient W _l (k), the following equation).

  The determination result signal P, which is the result of determining the disappearance interval, is the absolute value of the ME value obtained from the data signal Data with improved quality and the transmission path information (CSI) derived from a plurality of systems in the ME operation unit 85. Based on the value, the total determination unit 90 determines the disappearance section.

  These outputs (data signal Data, absolute value of transmission path information (CSI), determination result signal P) are input to the time de-interleave unit 56, and the following processing is performed.

  This diversity can be combined with all embodiments to improve the quality of the signal data.

(Experimental result)
The effects of the prior art and the present invention were verified.

  (A) When time interleaving is not performed, (b) When time interleaving is performed but erasure determination is not performed, (c) Time interleaving in an environment where the pulse interference is large (condition that the noise intensity is 10 times or more of the signal intensity) In the three cases where both the erasure determination and the erasure determination are performed, the ratio of occurrence of bit errors was compared.

As a result, the BER (Bit Error Ratio) was 5 × 10 ⁻⁵ in the case of (a), but the time interleaving in (b) only improved slightly to 3 × 10 ^−5. there were. However, in the case of (c) of the present invention, the BER was greatly improved to 5 × 10 ⁻⁷ or less, demonstrating the effect of the present invention.

  Although the above embodiment has been described as a representative example, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, a plurality of constituent blocks described in the embodiments can be combined into one, or one constituent block can be divided.

DESCRIPTION OF SYMBOLS 10 Transmission apparatus 11 Transmission apparatus 12 Information source encoding part 13 Transmission path encoding part 14 Frequency conversion part 15 Power amplification part 16 Error correction encoding part 17 Carrier modulation part 18 Time interleaving part 19 Complex signal modulation part 20 Reception apparatus 21 Reception Device 22 Reception amplification unit 23 Frequency conversion unit 24 Transmission path decoding unit 25 Information source decoding unit 26 Complex signal demodulation unit 27 Time de-interleaving unit 28 Carrier demodulation unit 29 Error correction decoding unit 31 Energy spreading unit 32 Error correction encoding unit 33 Carrier modulation unit 34 Bit rotation unit 35 Mapping unit 36 Frequency interleaving unit 37 Time interleaving unit 40 OFDM frame configuration unit 41 IFFT (Inverse Fast Fourier Transform) unit 42 Guard interval addition unit 51 Window processing unit 52 FFT (Fast Fourier Transform) unit 53 OFDM frame de multi Plex unit 54 Interpolation filter unit 55 Complex division unit 56 Time de-interleaving unit 57 Frequency de-interleaving unit 58 Carrier demodulation unit 59 De-mapping unit 60 Bit de-interleaving unit 61 Error correction decoding unit 62 Energy despreading unit 80 Erasure period Determination unit 81 Mechanism for performing interval disappearance processing 82 Signal absolute value calculation unit 83 Signal absolute value determination unit 84 Multiplier 85 ME calculation unit 86 ME determination unit 87 Pulse interval estimation unit 88 CSI absolute value calculation unit 89 CSI absolute value determination unit 90 Comprehensive determination unit 91 Multiplier 92 Multiplier 93 Error correction soft decision decoding unit 94 Diversity combining unit 95 Diversity combining weight coefficient generation unit 96 Multiplier 97 Combiner

Claims (13)

In a digital wireless microphone receiver comprising at least a complex signal demodulator that demodulates a complex signal from a received signal, a time de-interleave unit, a carrier demodulator, an error correction decoder, and an information source decoder
An erasure section determination unit that determines a section in which the received signal is disturbed by pulse noise,
An apparatus for receiving a digital wireless microphone, which performs error correction decoding after performing erasure processing in which signal data of a section subjected to interference is zero based on a determination result of the erasure section determination section. A complex signal demodulator that demodulates a complex signal from a received signal; an erasure interval determiner that determines an interval in which the received signal is disturbed by pulse noise; a time deinterleaver; a carrier demodulator; and an error correction decoder And a digital wireless microphone receiving device comprising at least an information source decoding unit,
The erasure interval determination unit is configured such that when the absolute value (| S |) of the signal obtained from the complex signal demodulation unit is equal to or greater than a predetermined threshold (Wth), the received signal is disturbed by pulse noise. Judged as an interval,
A receiver for a digital wireless microphone, wherein error correction is performed after erasure processing in which signal data in the section subjected to the interference is zeroed. The receiver for a digital wireless microphone according to claim 2,
The erasure interval determination unit includes a signal absolute value calculation unit that derives an absolute value (| S |) of a signal obtained from the complex signal demodulation unit, and an absolute value (| S | derived by the signal absolute value calculation unit). ) Is 1 when the threshold value (Wth) is lower than the threshold value (Wth), and 0 when the threshold value (Wth) is greater than or equal to the threshold value (Wth).
A digital wireless microphone receiving apparatus, wherein error correction is performed after a process of multiplying the determination result signal (P) by signal data of a corresponding section. A complex signal demodulator that demodulates a complex signal from a received signal; an erasure interval determiner that determines an interval in which the received signal is disturbed by pulse noise; a time deinterleaver; a carrier demodulator; and an error correction decoder And a digital wireless microphone receiving device comprising at least an information source decoding unit,
The erasure interval determination unit is configured to receive the interference of the received signal due to pulse noise when a modulation error (ME) of the signal obtained from the complex signal demodulation unit is equal to or greater than a predetermined threshold (MEth). And determine
A receiver for a digital wireless microphone, wherein error correction is performed after erasure processing in which signal data in the section subjected to the interference is zeroed. The receiver for a digital wireless microphone according to claim 4,
The erasure interval determination unit includes an ME operation unit that calculates a modulation error (ME) of a signal obtained from the complex signal demodulation unit, and a modulation error (ME) calculated by the ME operation unit. An ME determination unit that outputs a determination result signal (P), which is 1 when the value (MEth) is less than 0 and becomes 0 when the value is equal to or greater than the threshold (MEth);
A digital wireless microphone receiving apparatus, wherein error correction is performed after a process of multiplying the determination result signal (P) by signal data of a corresponding section. A complex signal demodulator that demodulates a complex signal from a received signal; an erasure interval determiner that determines an interval in which the received signal is disturbed by pulse noise; a time deinterleaver; a carrier demodulator; and an error correction decoder And a digital wireless microphone receiving device comprising at least an information source decoding unit,
The erasure interval determination unit is based on the absolute value (| S |) of the signal obtained from the complex signal demodulation unit and the modulation error (ME: Modulation Error) of the signal obtained from the complex signal demodulation unit. , Determine a section in which the received signal is disturbed by pulse noise,
A receiver for a digital wireless microphone, wherein error correction is performed after erasure processing in which signal data in the section subjected to the interference is zeroed. An OFDM complex signal demodulating unit that demodulates a complex signal from an OFDM received signal, an erasure interval determining unit that determines an interval in which the OFDM received signal is disturbed by pulse noise, a time de-interleave unit, a carrier demodulation unit, In a digital wireless microphone receiving apparatus comprising at least an error correction decoding unit and an information source decoding unit,
When the absolute value (| CSI |) of the transmission path information is equal to or greater than a predetermined threshold (Wth), the erasure section determination unit determines that the OFDM reception signal is a section that has been disturbed by pulse noise;
A receiver for a digital wireless microphone, wherein error correction is performed after erasure processing in which signal data in the section subjected to the interference is zeroed. The receiver for a digital wireless microphone according to claim 7,
The erasure interval determination unit includes a CSI absolute value calculation unit that calculates an absolute value (| CSI |) of the transmission path information, and an absolute value (| CSI |) calculated by the CSI absolute value calculation unit as the threshold value. A CSI absolute value determination unit that outputs a determination result signal (P), which is 1 when the value is less than (Wth) and is 0 when the value is equal to or greater than the threshold value (Wth),
A digital wireless microphone receiving apparatus, wherein error correction is performed after a process of multiplying the determination result signal (P) by signal data of a corresponding section. An OFDM complex signal demodulating unit that demodulates a complex signal from an OFDM received signal, an erasure interval determining unit that determines an interval in which the OFDM received signal is disturbed by pulse noise, a time de-interleave unit, a carrier demodulation unit, In a digital wireless microphone receiving apparatus comprising at least an error correction decoding unit and an information source decoding unit,
The erasure interval determination unit is configured to block the received signal from being disturbed by pulse noise when a modulation error (ME) of the signal obtained from the OFDM complex signal demodulation unit is equal to or greater than a predetermined threshold (MEth). Judged as the received section,
A receiver for a digital wireless microphone, wherein error correction is performed after erasure processing in which signal data in the section subjected to the interference is zeroed. The digital wireless microphone receiver according to claim 9,
The erasure interval determination unit includes an ME calculation unit that calculates a modulation error (ME) of a signal obtained from the OFDM complex signal demodulation unit, and a modulation error (ME) calculated by the ME calculation unit. An ME determination unit that outputs a determination result signal (P), which is 1 when the threshold value (MEth) is lower than the threshold value (MEth);
A digital wireless microphone receiving apparatus, wherein error correction is performed after a process of multiplying the determination result signal (P) by signal data of a corresponding section. An OFDM complex signal demodulating unit that demodulates a complex signal from an OFDM received signal, an erasure interval determining unit that determines an interval in which the OFDM received signal is disturbed by pulse noise, a time de-interleave unit, a carrier demodulation unit, In a digital wireless microphone receiving apparatus comprising at least an error correction decoding unit and an information source decoding unit,
The erasure interval determination unit determines that the received signal is pulsed based on an absolute value (| CSI |) of transmission path information and a modulation error (ME) of the signal obtained from the OFDM complex signal demodulation unit. Determine the section that was disturbed by the noise,
A receiver for a digital wireless microphone, wherein error correction is performed after erasure processing in which signal data in the section subjected to the interference is zeroed. The digital wireless microphone receiving device according to any one of claims 7, 8, and 11,
The erasure section determination unit obtains a determination result signal (P) in which the section where the OFDM reception signal is not disturbed by pulse noise is 1 and the section where the OFDM reception signal is disturbed by pulse noise is 0. Output,
After performing the process of multiplying the determination result signal (P), the absolute value (| CSI |) of the transmission path information, and the signal data of the corresponding section, soft decision decoding for error correction is performed. Digital wireless microphone receiver. In the receiver for digital wireless microphones according to any one of claims 1 to 12,
A receiver for a digital wireless microphone, wherein reception is performed by a diversity method, and a norm operation is used as an absolute value (| CSI |) of transmission path information of each branch in a diversity combining type.

Images