JP4915588B2 - Receiver - Google Patents

Description

  The present invention relates to a receiving apparatus in a UWB communication system using an ultrashort pulse wave of 1 ns or less.

  In recent years, in order to transmit detection information of various sensors, switch operation information, and the like by wireless communication, it has been proposed to employ an ultra wide band (hereinafter referred to as “UWB”) communication method. . In the UWB communication system, the frequency to be used is the GHz band (3.1 to 10.6 GHz), and the bandwidth is specified to be 25% or more of the central frequency for communication or 500 MHz or more.

  In the UWB communication system, it is common to use an ultrashort pulse wave of 1 ns or less. Therefore, in radio communication, the time for radiating a radio signal is extremely short, and there is an advantage that power consumption can be greatly reduced as compared with a conventional communication system in which a carrier wave is radiated continuously. In addition, because data is transmitted using ultrashort pulses and the occupation time during data transmission is very small, receiving data so as to synchronize with the transmission of ultrashort pulses is affected by multipath. It becomes difficult to receive interference generated from other wireless communication systems.

  Various modulation schemes in wireless communication using the UWB communication scheme have been proposed, such as PPM (Pulse Position Modulation), OOK (On Off Keying), PAM (Pulse Amplitude Modulation), etc. UWB-IR (Ultra Wide Band-Impulse Radio) to be used is known.

  Here, OOK represents a data value depending on the presence / absence of a pulse, similarly to ASK (Amplitude Shift Keying). Therefore, when OOK is used, non-coherent communication that does not use phase information for data values becomes possible.

  In order to perform data communication, it is necessary to detect the reference position of the data transmitted from the transmission device at the reception device. That is, it is necessary to synchronize data between the transmission device and the reception device. Therefore, a technique is considered in which a period for transmitting a synchronization signal pattern from a transmission device is provided before a pulse train representing data, and the reception device receives the synchronization signal pattern to synchronize the transmission device and the reception device ( For example, see Patent Document 1).

  On the other hand, as a configuration example using UWB-IR, there has been proposed a configuration in which BPSK (Binary Phase Shift Keying) modulation is performed in a transmission device and QPSK (Quadrature Phase Shift Keying) demodulation is performed in a reception device (for example, Patent Documents). 2).

In the technique described in Patent Document 2, as shown in FIG. 6, after the reception signal received by the antenna 6 is amplified by the low noise amplifier 7 ′ in the receiving apparatus, the frequency substantially matches the carrier wave of the received signal (Patent Document 2). Is generated by using the clock generator 10 and the π / 2 phase shifter 11a, and two received signals are input. By inputting clock signals having different phases to the mixers 11b and 11c, the in-phase component I signal and the quadrature component Q signal are extracted from the mixers 11b and 11c. The carrier waves of the received signal are removed from the outputs of the mixers 11b and 11c by the filters 2a and 2b, and Gaussian monopulses for each phase are extracted as the outputs of the filters 2a and 2b.
JP 2006-94169 A JP 2007-71819 A

  By the way, in a receiving apparatus used for wireless communication, a filter for extracting a target wireless signal is provided in order to distinguish a target wireless signal transmitting information from other wireless signals (that is, interference waves). In the receiving apparatus that performs communication using the UWB communication method described in Patent Document 1, a filter is provided in the pulse demodulation unit in order to extract a target radio signal used for data transmission.

  However, in the UWB communication system, the center frequency of the frequency received by the receiving device is the GHz band (for example, 4 GHz), and the bandwidth of the pass band required for the filter is very wide. The realization of is accompanied by difficulties. If the center frequency is about 2 GHz or less, it is relatively easy to construct an active filter using active elements by diverting the high-frequency circuit technology employed in mobile phones and wireless LANs. It is difficult to construct an active filter at about 4 GHz.

  Therefore, in order to eliminate the effects of various interference waves, a filter with multiple types of characteristics is prepared for each interference wave, and a filter that matches the interference wave present in the usage environment is selected. As a result, there is a problem that the cost is increased and the size is increased.

  In addition, since the configuration described in Patent Document 2 is UWB-IR and uses phase information for data transmission, a carrier wave for transmitting data is required in the transmission device, and the configuration of the transmission device is complicated. There is a problem that the cost increases.

  On the other hand, in the receiving apparatus, since the Gaussian monopulse is extracted by the clock signal having the same frequency as the carrier wave for transmitting data, the filters 2a and 2b may be low-pass filters for removing the carrier frequency (or the clock signal frequency). , 2b is easy to design. However, in the receiving apparatus, two mixers 11b and 11c are required, and clock signals having different phases must be input to the mixers 11b and 11c. Therefore, the structure of the receiving apparatus becomes complicated and the cost increases. There is a problem.

  The present invention has been made in view of the above-mentioned reasons, and its purpose is to make it possible to design a filter for selectively separating ultrashort pulse waves used in an ultra-wideband communication system by utilizing the state of the art, and to use the phase. It is an object of the present invention to provide a receiving apparatus that can be realized with a simple circuit configuration together with a transmitting apparatus by transmitting data without performing the above process.

According to the first aspect of the present invention, there is provided a synchronization pulse train not including data using an ultrashort pulse wave of 1 ns or less transmitted from a transmission device using a transmission window generated at a transmission interval of a fixed time, and a data pulse train including data. Is a receiver that is used in an ultra-wideband communication system that transmits non-coherent data by transmitting a frame having a transmission from the transmitter , and performs expansion of the received signal to perform frequency conversion and output an intermediate signal having a frequency lower than that of the received signal A filter that selects and passes an intermediate signal corresponding to the target ultrashort pulse wave among the intermediate signals, a detector that detects a target pulse from the intermediate signal that has passed through the filter, and a target pulse A pulse detector that outputs a signal pulse by identifying and position identification, and a bit of data by the signal pulse output from the pulse detector The decompressor includes an oscillator that outputs a local oscillation signal having a constant frequency different from that of the reception signal, and a mixer that multiplies the reception signal and the local oscillation signal. There line frequency conversion as the upper limit of the passband of and filter have the same bandwidth as the ultra-short pulse wave is lower than the frequency of the lower limit of the ultra short pulse waves of interest to, and frequency conversion of the received signal The timing of the reception period that is a period of performing the period and the time width of the reception period can be adjusted by a period control signal output from the pulse detector, and the pulse detector is in a period in which the synchronization pulse train is generated, It operates in the search mode that detects the reception timing of the synchronization pulse train from the pulses output from the detector. In the search mode, the time interval for setting the reception period is changed every time, When Murrell ultrashort pulse wave is detected in any of the reception period, and wherein the switching time interval consistent with the time interval of the send window time interval of the reception period is generated.

In the invention of claim 2, the invention odor Te claim 1, before Symbol pulse detector, have a data mode for extracting a signal pulse from the data pulse train based on the reception timing of the synchronization pulse train detected by the sub Chimodo and, wherein the decompressor is in the period even without least the pulse detector is operating in the data mode, and characterized in that intermittently operating the expander each reception period synchronized with the reception timing of de Taparusu column .

  The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the oscillator is capable of adjusting a local oscillation frequency of a local oscillation signal to be output by a frequency control signal from the pulse detector. To do.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the pass band of the filter can be adjusted by a band control signal from the pulse detector.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the expander includes a first amplifier that amplifies an intermediate signal, and the amplification factor of the first amplifier is the pulse detector. The first gain control signal can be adjusted by the first gain control signal.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the expander includes a second amplifier that amplifies a local oscillation signal output from the oscillator, and amplifies the second amplifier. The rate is adjustable by a second gain control signal from the pulse detector.

  According to a seventh aspect of the present invention, there is provided the reception according to any one of the first to sixth aspects, wherein the transmitting device transmits an ultrashort pulse wave representing the same bit value continuously in a plurality of prescribed times. An integrator that integrates intermediate signals in the plurality of periods between the detector and the pulse detector, wherein the pulse detector is an intermediate signal integrated for each bit value by the integrator; Is used to output a signal pulse.

  According to the configuration of the first aspect of the present invention, data is transmitted non-coherently, so that the intended ultrashort pulse wave is independent of the phase of the local signal output from the oscillator, and two oscillators and two mixers are provided. It is not necessary to employ a configuration in which each phase is provided and the phase is detected, and can be realized with a simple circuit configuration together with the transmission device.

  In addition, frequency conversion to an intermediate signal having a frequency lower than the frequency of the received signal is performed using an expander, and the intermediate signal has the same bandwidth as the intended ultrashort pulse wave and the pass band of the filter. Frequency conversion is performed so that the upper limit of the received signal is lower than the lower limit frequency of the intended ultrashort pulse wave. For example, if the center frequency of the received signal is about 4 GHz, the intermediate signal is converted to 2 GHz or less. This makes it possible to design a filter using a high-frequency circuit technology adopted in a mobile phone or a wireless LAN, and even an active filter using an active element can be easily realized. . That is, the filter can be easily integrated, and the pass band of the filter can be adjusted with high accuracy and easily, and the cost and size can be reduced.

  By making it possible to adjust the passband of the filter with high accuracy and ease, it is possible to separate interference waves and unwanted waves that are different from the target ultrashort pulse wave by adjusting the frequency characteristics of the filter. This makes it possible to configure a receiving apparatus that is less susceptible to interference waves and unwanted waves.

Furthermore, since the upper limit of the passband of the filter is set lower than the lower limit frequency of the ultrashort pulse wave, the frequency of the local oscillation signal output from the oscillator is sufficiently higher than the frequency of the received signal. Thus, an intermediate signal that is irrelevant to the phase relationship between the received signal and the local signal can be obtained. In other words, if the frequency difference between the center frequency of the received ultrashort pulse wave and the frequency of the local oscillation signal output from the oscillator is small, depending on the phase relationship between the two, it may be difficult to obtain an output as an intermediate signal, The signal may be detected even if there is no received signal by self-mixing the local oscillation signal output from the signal, but since the frequency difference is sufficiently large, the intermediate signal is taken out regardless of the phase relationship As a result, the signal pulse corresponding to the ultrashort pulse wave can be accurately extracted without self-mixing.
In addition, the time interval for setting the reception period in the search mode is changed every time, and when an ultrashort pulse wave included in the synchronization pulse train is detected in any reception period, the transmission window generates the time interval of the reception period. Therefore, the transmission device and the reception device can be synchronized.

  According to the configuration of the invention of claim 2, the timing for receiving the ultrashort pulse wave is determined using the synchronization pulse train, and the reception period is set so that the expander is operated intermittently at the determined timing. By performing frequency conversion by the expander using only the period during which the ultra-short pulse wave is transmitted from the device as the reception period, interference waves and unwanted waves that occur outside the period during which the target ultra-short pulse wave is transmitted Can be separated by time. In addition, a pulse train for synchronization and a data pulse train are provided in a frame transmitted from the transmission device, and the pulse detector has a search mode and a data mode. Therefore, in the search mode, an ultrashort pulse is transmitted from the transmission device by the synchronization pulse train. The timing at which the wave is transmitted can be detected, and the reception period for the data pulse train can be controlled in the subsequent data mode. Furthermore, although the expander is operated intermittently, if the filter and detector are in an active configuration, if the filter and detector are operated intermittently in synchronization with the operation of the expander, Interference wave and unnecessary wave separation performance is further enhanced.

  According to the configuration of the invention of claim 3, since the pulse detector controls the frequency of the local oscillation signal output from the oscillator provided in the expander, for example, the frequency of the intermediate signal obtained by frequency-converting the interference wave and the unnecessary wave is By adjusting the frequency of the local oscillation signal so as to be excluded from the pass band of the filter, it is possible to reduce the influence of interference waves and unnecessary waves. Alternatively, the frequency of the local oscillation signal can be adjusted so that the signal level of the intermediate signal corresponding to the target ultrashort pulse wave is increased in the pulse detector.

  According to the configuration of the fourth aspect of the invention, since the pulse detector controls the pass band of the filter, for example, the filter is arranged so that the frequency of the intermediate signal corresponding to the interference wave and the unnecessary wave is excluded from the pass band of the filter. By adjusting the passband, the influence of interference waves and unnecessary waves can be reduced. Alternatively, it is possible to adjust the pass band of the filter so that the signal level of the intermediate signal corresponding to the target ultrashort pulse wave is increased in the pulse detector.

  According to the configuration of the invention of claim 5, since the amplification factor of the intermediate signal output from the pulse expander can be adjusted, the signal level of the intermediate signal is optimized so that saturation and SNR do not decrease. The signal pulse can be extracted with high accuracy. In other words, when there is a level difference in the signal level between the target ultrashort pulse wave and the interference wave or unnecessary wave, it is easy to separate the two using the level difference by optimizing the amplification factor.

  According to the configuration of the sixth aspect of the invention, since the signal level of the local signal input to the mixer can be adjusted, the signal level of the intermediate signal can be adjusted, so that saturation occurs or SNR decreases. Therefore, the signal level of the intermediate signal is optimized so that the signal pulse can be extracted with high accuracy. In other words, when there is a level difference in the signal level between the intended ultrashort pulse wave and the interference wave or unwanted wave, it is easy to separate the two using the level difference by optimizing the signal level of the local signal. become.

  According to the configuration of the seventh aspect of the invention, since the same bit value is transmitted from the transmission device a plurality of times in advance, and the reception device integrates signals of the same bit value using the integrator, When there is a level difference in the signal level between the pulse wave, interference wave, and unwanted wave, the level difference can be increased by integration, making it easy to separate the desired ultrashort pulse wave from the interference wave and unwanted wave. become.

(Embodiment 1)
As shown in FIG. 1, the present embodiment includes an expander 1 that performs frequency conversion (down-conversion) on a received signal obtained by receiving a radio signal transmitted from a transmitting device Tx and outputs an intermediate signal. , A filter 2 having a frequency range defined for the intermediate signal output from the expander 1, a detector 9 for detecting a pulse from the intermediate signal that has passed through the filter 2, and pulse identification and position identification A pulse extraction unit 5 including a pulse detector 3 that performs a signal pulse (described later) is provided. The expander 1 includes an oscillator 1a that outputs a local oscillation signal having a frequency f2 having a frequency difference sufficiently large (described later) with respect to the frequency f1 of the received signal (the frequency f1 represents the center frequency of the received signal); A mixer 1b for mixing the received signal and the local signal is provided. The mixer 1b outputs an intermediate signal obtained by multiplying the reception signal and the local oscillation signal.

  The front stage of the pulse extraction unit 5 includes an antenna 6 that receives a radio signal from the transmission device Tx, and a front end 7 that includes a low-noise amplifier (not shown) that amplifies the reception signal output from the antenna 6. It is done. In addition, a bit determination unit 4 that extracts a bit value of a radio signal transmitted from the transmission device by a signal pulse output from the pulse detector 3 is provided at the subsequent stage of the pulse extraction unit 5. The output of the bit determination unit 4 is used as data received from the transmission device.

  As described above, in the pulse extraction unit 5, the received signal is passed through the expander 1, the filter 2, and the detector 9 before the received signal output from the front end 7 is input to the pulse detector 3. The oscillator 1a provided in the expander 1 outputs a local oscillation signal having a frequency difference of several hundred MHz or more (for example, 1 GHz or more) with respect to the frequency f1 of the reception signal. That is, a station that outputs from the oscillator 1a so that the intermediate signal has the same bandwidth as the target ultrashort pulse wave and the upper limit of the pass band of the filter 2 is lower than the lower limit frequency of the target ultrashort pulse wave. The frequency f2 of the emitted signal is set.

Assume that the frequency f2 of the local oscillation signal output from the oscillator 1b is set to a lower frequency than the frequency f1 of the received signal (f1> f2). By setting the frequency f2 of the local oscillation signal lower than the frequency f1 of the reception signal, the design of the oscillator 1a becomes easier as compared with the case where it is set higher than the frequency f1 of the reception signal. When data is transmitted non-coherently, the phase difference between the received signal and the local signal is irrelevant, so that the following relationship can be obtained by focusing only on the frequency.
a (t) = A · sin (ω1 · t)
b (t) = B · sin (ω2 · t)
However, a (t) is the received signal, b (t) is the local signal, A and B are the amplitudes of the received signal and the local signal, ω1 = 2π · f1, and ω2 = 2π · f2. Since the mixer 1b that mixes the received signal and the local signal output from the oscillator 1a functions as a multiplier, the output of the mixer 1b has a relationship of the following equation obtained by multiplying the above two equations.
a (t) · b (t) = A · B · sin (ω1 · t) · sin (ω2 · t)
= (AB / 2) {cos (ω1-ω2) t-cos (ω1 + ω2) t}
That is, the output of the mixer 1b includes frequency components of (f1 + f2) and (f1-f2). By extracting (f1-f2) on the low frequency side from both frequency components, the received signal is frequency-converted from frequency f1 to a frequency lower by frequency f2. That is, by passing the output of the mixer 1b through the filter 2 and setting the pass band characteristic of the filter 2 so that the frequency component (f1 + f2) does not pass, the received signal is down-converted.

  At least one of the signal level of the local signal output from the oscillator 1a constituting the expander 1 and the signal level of the intermediate signal output from the mixer 1b is variable stepwise or continuously. Specifically, an amplifier (second amplifier; not shown) that amplifies the local signal output from the oscillator 1a and an amplifier (first amplifier; not shown) that amplifies the intermediate signal output from the mixer 1b. ), And the amplification factor of each amplifier can be individually adjusted by an amplification factor control signal output from the pulse detector 3.

  As is apparent from the above equation, the signal level of the intermediate signal output from the mixer 1b can be changed by changing the amplitude B of the local oscillation signal input to the mixer 1b. Since the signal level of the intermediate signal input to the filter 2 can be adjusted, the SNR can be increased or saturation can be prevented within the dynamic range of the pulse extraction unit 5. As a result, when there is a level difference in the signal level between the target ultrashort pulse wave and the interference wave or unwanted wave, it is possible to easily separate the two by using the level difference by optimizing the amplification factor. Become. For example, by setting an appropriate threshold value for the signal level, it is possible to separate the ultrashort pulse wave from the interference wave and the unnecessary wave.

  By performing the down-conversion as described above, the passband characteristic of the filter 2 can be lowered from the frequency f1 of the received signal as shown in FIG. 2A (the frequency f1 of the received signal and the local signal). The frequency can be lowered to a frequency difference (f1-f2) with respect to the frequency f2. As a result, the filter 2 having a frequency lower than the frequency f1 of the received signal (f1 has a bandwidth corresponding to the pass band of the filter 2 instead of a single frequency) can be used, The pass band of the filter 2 can be greatly reduced as compared with the case where the expander 1 is not used. For example, if the center frequency f1 of the received signal is 4 GHz and the frequency f2 of the local signal is 2.6 GHz, the center frequency of the pass band of the filter 2 can be 1.4 GHz.

  The local oscillation signal output from the oscillator 1a used for the expander 1 may not be a sine wave. When a local oscillation signal other than a sine wave is used, an intermediate signal of the frequency difference between the received signal and the harmonic component of the local oscillation signal is also obtained at the output of the mixer 1b. Assuming that the fundamental frequency of the local signal output from the oscillator 1a is f3, the frequency f1 of the received signal and the frequency f3 of the local signal are (f1-f3) as shown in FIG. And (f1 + f3), intermediate signals such as (f1-2f3), (f1-3f3), (f1-4f3), (f1 + 2f3), and (f1 + 3f3) are output from the expander 1.

  By selecting an intermediate signal having a desired frequency from such an intermediate signal by the filter 2, it is possible to extract an intermediate signal obtained by down-converting the received signal as in the case of using a sinusoidal local oscillation signal. Here, a filter 2 having a passband center frequency (f1-f2) is used, and an intermediate signal having a frequency (f1-2f3) is extracted by the filter 2 from the intermediate signals output from the expander 1. Then, since f3 = f2 / 2, the output frequency of the oscillator 1a can be lowered as compared with the case of using a sine wave local oscillation signal. That is, it becomes easy to design and manufacture the oscillator 1a.

  At the current technical level, if the frequency is 2 GHz or less, the filter 2 can be configured using a high-frequency circuit technology and an electronic device used in a mobile phone, a wireless LAN, and the like, so that the center frequency is 4 GHz or more. The design is easier than when the filter 2 is configured. The filter 2 as a whole is a combination of a broadband bandpass filter of 500 MHz or higher and a notch filter (band eliminated filter) that attenuates a specific frequency band. Therefore, the resonance circuit is configured by combining active elements.

  A microstrip line and a ceramic filter are used for the resonance circuit. When configuring a filter having a center frequency of 4 GHz or more, it is necessary to use an individual element as an active element. However, in this embodiment, since the pass band of the filter 2 is 2 GHz or less, an operational amplifier is used as the active element. Such an integrated circuit can be used, and the filter 2 can be integrated.

  The filter 2 can adjust the center frequency and bandwidth as a band-pass filter and the center frequency and bandwidth as a notch filter by a band control signal supplied from the pulse detector 3. That is, the pass band of the filter 2 can be adjusted by the band control signal. For this adjustment, it is possible to employ a configuration in which a plurality of specific resonance circuits are provided, and one of the resonance circuits is selected by a band control signal so that the pass band is changed stepwise. Alternatively, it is possible to employ a configuration in which an electronic device capable of adjusting the electrostatic capacity by an external signal such as a variable capacitance diode is provided in the resonance circuit, and the frequency is continuously changed.

  As described above, since the pulse detector 3 controls the pass band of the filter 2, the pass band of the filter 2 is adjusted so that the frequency of the intermediate signal corresponding to the interference wave or the unnecessary wave is excluded from the pass band of the filter. If so, the influence of interference waves and unnecessary waves can be reduced. To eliminate interference and unwanted waves, not only adjust the center frequency and bandwidth of the bandpass filter, but also remove the interference and unwanted waves by adjusting the center frequency and bandwidth of the notch filter. be able to. By adjusting the pass band of the filter 2 using the band control signal, the signal level of the intermediate signal corresponding to the target ultrashort pulse wave can be relatively increased in the pulse detector 3.

  On the other hand, the radio signal transmitted from the transmitter Tx is composed of ultrashort pulse waves of 1 ns or less, but each ultrashort pulse wave is actually a burst wave as shown in FIG. The ultrashort pulse wave is transmitted from the transmission device Tx at a transmission interval of a certain time (for example, set to 30 ns, 57 ns, etc.). The duration of the burst wave is about 2 ns, and one period of the burst wave is 1 ns or less (about several hundreds ps). The frequency of the ultrashort pulse wave used in the UWB communication system means the reciprocal of this period.

  In the transmission device Tx, the phase information is not used to distinguish the data value (bit value), and as shown in FIG. 3B, the ultrashort pulse wave in the transmission window Wt, which is a specified time slot of a predetermined time, is used. Presence / absence is used as a bit value. For example, the bit value when an ultrashort pulse wave is put into the transmission window Wt is set to 1, and the bit value when no ultrashort pulse wave is put into the transmission window Wt is set to 0. By such an operation, non-coherent communication without using phase information can be performed.

  In the reception device Rx, as shown in FIG. 3C, the reception period Pr corresponding to the transmission window Wt set in the transmission device Tx is set. If the transmission device Tx defines the relationship between the presence / absence of the signal of the transmission window Wt and the bit value as described above, the bit value is obtained when a radio signal of an ultrashort pulse wave is received in the set reception period Pr. 1 is output, and a bit value of 0 is output when not received. With this operation, the data transmitted from the transmission device Tx can be extracted by the reception device Rx.

  The reception period Pr in the reception device Rx may have a time width equal to or longer than one period of the ultrashort pulse wave. The larger the time width of the reception period Pr, the easier it is to receive interference from other signals. The smaller the time width is, the more time is required for the process of synchronizing with the transmission device Tx. Therefore, it is desirable to set the time width of the reception period Pr set in the receiving device Rx to about 2 to 5 times the period of the ultrashort pulse wave.

  The filter 2 is set to have a pass band so as to pass an intermediate signal and not allow interference waves or unnecessary waves (hereinafter referred to as “interference waves”) to pass. That is, if the oscillator 1a is controlled so that the local oscillation signal is output from the oscillator 1a only during the reception period Pr, even if an interference wave within the frequency range of the ultrashort pulse wave is received during the period other than the reception period Pr, the expansion is performed. Since the output of the filter 1 is not frequency-converted to the pass band of the filter 2, it cannot pass through the filter 2, and an interference wave can be removed from the output of the filter 2. Further, when the interference wave is received in the reception period Pr and the frequency of the interference wave is included in the target ultrashort pulse wave frequency range, the interference wave and the target ultrashort pulse wave are distinguished. However, if the pass band of the filter 2 is set so as to remove the frequency component of the interference wave that has been confirmed to exist in the usage environment of the receiving device Rx, this type of interference wave can be removed. Is possible.

  As the detector 9, a square detector or an absolute value circuit is used. That is, the detector 9 performs envelope detection for extracting the envelope of the intermediate signal. Therefore, a pulse corresponding to the envelope of the ultrashort pulse wave is output from the detector 9.

  The pulse detector 3 identifies the target pulse (hereinafter referred to as “target wave” when distinguishing the target ultrashort pulse wave from the interference wave) by identifying the pulse output from the detector 9 and identifying the position. And the extracted pulse is output as a signal pulse. The pulse detector 3 has a function of outputting the above-described amplification factor control signal and band control signal, controlling the expander 1 to determine the reception period Pr, and outputting a period control signal. It has a function of adjusting the frequency f2 of the local oscillation signal by giving a frequency control signal to the oscillator 1a.

Since the frequency f2 of the local signal output from the oscillator 1 can be adjusted , the frequency f2 of the local signal can be adjusted so that the intermediate signal of the interference wave is outside the pass band of the filter 2. In some cases, such adjustment increases the possibility of removing the interference wave. That is, the influence of the interference wave can be reduced. It is also possible to adjust the frequency f2 of the local oscillation signal so that the signal level of the intermediate signal corresponding to the target wave is increased in the pulse detector 3. It is desirable to control the frequency control signal and the band control signal described above in conjunction with each other. In particular, since the center frequency of the notch filter for removing the interference wave needs to coincide with the intermediate signal related to the interference wave, it is desirable to link the frequency control signal and the band control signal.

  As is clear from the above description, in the pulse extraction unit 5, in order to separate the interference wave from the target wave, the reception period Pr is set according to the target wave, and the frequency band in which the interference wave exists is set. The technique of separating the target wave from the target wave and the technique of separating the interference wave based on the signal level difference between the interference wave and the target wave are used together. In other words, by limiting the time for extracting the target wave from the received signal in the pulse extraction unit 5, the interference wave generated at a time different from the target wave is removed, and the interference generated at the same time as the target wave Waves are removed by using differences in frequency components and signal level differences.

  The pulse extraction unit 5 physically removes the interference wave, but the interference wave cannot always be completely removed, so the output from the pulse extraction unit 5 is logically determined by the bit determination unit 4, If the bit value extracted by the pulse extraction unit 5 is not correct, the data is discarded. Whether the bit value is correct or not is determined by inserting a bit synchronization pulse train SB (see FIG. 4) before the data when transmitting a radio signal from the transmission device Tx, and then receiving the bit synchronization pulse train SB in the reception device Rx (bit determination unit 4). What is necessary is just to confirm by collating. The bit determination unit 4 can also confirm whether the bit value is correct or not by using a code error detection technique such as a checksum. The processing after discarding data is a known processing such as a retransmission request.

  Below, the function which determines the reception period Pr in the pulse detector 3 is demonstrated concretely. The reception period Pr is determined so that the timing at which the transmission device Tx generates the target wave coincides with the timing at which the reception device Rx generates the local oscillation signal from the oscillator 1a. A state in which both timings coincide with each other corresponds to that the transmission device Tx and the reception device Rx operate in synchronization. In order to synchronize the transmission device Tx and the reception device Rx, one frame of a radio signal transmitted from the transmission device Tx includes a synchronization pulse train SY as shown in FIG. Further, as described above, the bit synchronization pulse train SB used in the bit determination unit 4 is also included. The data pulse train DT is transmitted after the synchronization pulse train SY and the bit synchronization pulse train SB. On the other hand, as shown in FIG. 4B, the reception device Rx (pulse detector 3) defines the timing of the reception period Pr so as to be synchronized with the transmission device Tx using the synchronization pulse train SY.

  The synchronization pulse train SY uses an ultrashort pulse wave in the same manner as the data pulse train DT. However, in the data string, the bit value is represented by the presence or absence of the ultrashort pulse train in the transmission window Wt, but in the synchronization pulse train SY, the ultrashort pulse train is displayed at a constant period so that the ultrashort pulse train exists in all the transmission windows Wt. generate.

  In a period in which the synchronization pulse train SY is generated, the pulse detector 3 operates in a search mode in which a time interval for providing the reception period Pr is changed. In the search mode, the time interval for providing the reception period Pr is changed every time (this time interval is set shorter than the time interval at which the transmission window Wt is generated), and the number of synchronization pulse trains SY and the reception period Pr By appropriately setting the time interval, frequency conversion of the ultrashort pulse wave included in the synchronization pulse train SY is performed in any reception period Pr within the period of receiving the synchronization pulse train SY. An intermediate signal corresponding to the ultrashort pulse wave can be obtained from the filter 2, and a pulse corresponding to the ultrashort pulse wave included in the synchronization pulse train SY is output from the detector 9. The pulse detector 3 has a function of comparing the signal level of the pulse output from the detector 9 with a prescribed threshold value, and excludes an intermediate signal whose signal level does not reach the prescribed threshold value as an interference wave.

  When an ultrashort pulse wave included in the synchronization pulse train SY is detected in any reception period Pr within the period in which the synchronization pulse train SY is generated, the pulse detector 3 shifts to the data mode, and the reception period The time interval of the reception period Pr after Pr is switched to a time interval that matches the time interval at which the transmission window Wt is generated in the transmission device Tx. With this operation, the transmission device Tx and the reception device Rx can be synchronized. In the data mode, the signal level for each reception period Pr is compared with a threshold value, and the magnitude relationship between the signal level and the threshold value is output as a signal pulse. For example, a signal pulse corresponding to a bit value of 1 is output when the signal level is equal to or higher than a threshold value, and a signal pulse corresponding to a bit value of 0 is output when the signal level is lower than the threshold value.

  That is, the pulse detector 3 identifies the position of the pulse that matches the reception period Pr in the search mode (identifies the time when the transmission device Tx generates the transmission window Wt), and determines whether there is a pulse at that position in the data mode. Identify.

  As described above, the pulse detector 3 normally operates in the search mode in which the time interval of the reception period Pr is changed. When the ultrashort pulse wave is detected in any reception period Pr in the search mode, the pulse detector 3 Until the end of one frame of the transmitted radio signal (until the end of the frame is notified from the bit determination unit 4 or until a state in which no signal pulse is generated reaches a specified time), the reception period Pr is set to the transmission window Wt. Operate in a data mode that matches the time interval at which is generated. Since the reception period Pr differs between the search mode and the data mode, by supplying a period control signal to the expander 1, at least one of the timing of the reception period Pr and the time width of the reception period Pr is controlled.

  Note that the transmitting device Tx and the receiving device Rx are provided with time measuring means (not shown) that measures at least the time interval, and both time measuring means have an accuracy that allows errors to be ignored within the time required for transmission of one frame. have. In the non-coherent UWB communication, it is only necessary to extract the target wave in the pulse detector 3, and it is not necessary to use all of the intermediate signal that has passed through the filter 2. Therefore, high stability is not required for the frequency of the intermediate signal. . Therefore, high stability is not required for the frequency f2 of the local oscillation signal output from the oscillator 1a, and the design is facilitated from this.

(Embodiment 2)
In the first embodiment, an example in which the receiving device Rx makes a retransmission request to the transmitting device Tx when the receiving device Rx fails to receive the data pulse train DT transmitted from the transmitting device Tx is described. The transmission device Tx repeatedly transmits the same bit value of the data pulse train DT a plurality of times, while the reception device Rx has an integrator 8 for integrating the pulses output from the detector 9 as shown in FIG. The structure to provide is adopted. The period in which the pulses are integrated by the integrator 8 is a period corresponding to the number of times of transmission of the ultrashort pulse wave in which the transmission device Tx represents the same bit value.

  That is, the integrator 8 integrates the output signal of the filter 2 in the data mode. In this configuration, the number of integrations in the integrator 8 is relatively large (for example, 10 times), and the output of the integrator 8 is binarized with an appropriate threshold in the pulse detector 3 to interfere with the target wave. Even if the waves overlap, if the number of times of overlap is small, it becomes possible to remove the influence of the interference wave and extract the target wave. The integrator 8 is controlled by the pulse detector 3. In the search mode, integration by the integrator 8 is not performed. Other configurations and operations are the same as those of the first embodiment.

1 is a block diagram illustrating a first embodiment. It is operation | movement explanatory drawing which shows the relationship of the frequency in the same as the above. It is operation | movement explanatory drawing which shows the timing of transmission / reception in the same as the above. It is operation | movement explanatory drawing which shows the flame | frame of the radio signal used for the same as the above. FIG. 6 is a block diagram illustrating a second embodiment. It is a block diagram of the principal part which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Expander 1a Oscillator 1b Mixer 2 Filter 3 Pulse detector 4 Bit judgment part 8 Integrator 9 Detector Rx Receiver Tx Transmitter

Claims (7)

A frame having a pulse train for synchronization not including data and a data pulse train including data is transmitted from the transmitter using an ultrashort pulse wave of 1 ns or less transmitted from the transmitter using a transmission window generated at a transmission interval of a fixed time. A receiving device for use in an ultra-wideband communication system that transmits and transmits non-coherent data, and performs a frequency conversion of a received signal and outputs an intermediate signal having a frequency lower than the received signal, and an intermediate signal A filter that selects and passes an intermediate signal corresponding to the target ultrashort pulse wave, a detector that detects the target pulse from the intermediate signal that has passed through the filter, and identification and position identification of the target pulse A pulse detector that outputs a signal pulse and a bit that extracts the bit value of the data using the signal pulse output from the pulse detector The decompressor includes an oscillator that outputs a local oscillation signal having a constant frequency different from that of the reception signal, and a mixer that multiplies the reception signal and the local oscillation signal. period limit of the passband have and filters the same bandwidth as the short pulse wave have line frequency conversion to be lower than the frequency of the lower limit of the ultra short pulse wave of interest, and performs frequency conversion of a received signal The timing of the reception period and the time width of the reception period can be adjusted by a period control signal output from the pulse detector, and the pulse detector is supplied from the detector during the period in which the synchronization pulse train is generated. It operates in the search mode that detects the reception timing of the synchronization pulse train from the output pulses. In the search mode, the time interval for setting the reception period is changed every time, and the ultrashort pulse included in the synchronization pulse train When There is detected in any of the reception period, the reception apparatus characterized by switching a time interval consistent with the time interval of the send window time interval of the reception period is generated. Before SL pulse detector has a data mode for extracting a signal pulse from the data pulse train based on the reception timing of the synchronization pulse train detected by the sub Chimodo, the decompressor, even without low pulse detector data in the period of operation mode, the receiving apparatus according to claim 1, characterized in that intermittently operating the expander each reception period synchronized with the reception timing of de Taparusu column.   The receiving apparatus according to claim 1 or 2, wherein the oscillator is capable of adjusting a local oscillation frequency of an output local oscillation signal by a frequency control signal from the pulse detector.   The receiving device according to any one of claims 1 to 3, wherein a pass band of the filter can be adjusted by a band control signal from the pulse detector.   The expander includes a first amplifier that amplifies an intermediate signal, and an amplification factor of the first amplifier is adjustable by a first amplification factor control signal from the pulse detector. The receiving device according to any one of claims 1 to 4.   The expander includes a second amplifier that amplifies a local oscillation signal output from the oscillator, and an amplification factor of the second amplifier can be adjusted by a second amplification factor control signal from the pulse detector. The receiving apparatus according to claim 1, wherein:   A receiving apparatus corresponding to a case where the transmitting apparatus transmits an ultrashort pulse wave representing the same bit value continuously for a plurality of prescribed times, the plurality of times between the detector and the pulse detector. 7. An integrator for accumulating intermediate signals in a period, and the pulse detector outputs a signal pulse using the intermediate signal integrated for each bit value by the integrator. The receiving device according to any one of claims.

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