WO2011123066A1 - Dispositif et procédé de traitement de signaux faisant intervenir une technique d'expansion temporelle - Google Patents

Dispositif et procédé de traitement de signaux faisant intervenir une technique d'expansion temporelle Download PDF

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Publication number
WO2011123066A1
WO2011123066A1 PCT/SG2011/000131 SG2011000131W WO2011123066A1 WO 2011123066 A1 WO2011123066 A1 WO 2011123066A1 SG 2011000131 W SG2011000131 W SG 2011000131W WO 2011123066 A1 WO2011123066 A1 WO 2011123066A1
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Prior art keywords
signal
periodic signal
pulse
output
waveform
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PCT/SG2011/000131
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English (en)
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WO2011123066A8 (fr
Inventor
Sivanand Krishnan
Hwee Woon Ong
Wenjiang Wang
Guoping Zhang
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Agency For Science, Technology And Research
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Priority to SG2012071452A priority Critical patent/SG184278A1/en
Publication of WO2011123066A1 publication Critical patent/WO2011123066A1/fr
Publication of WO2011123066A8 publication Critical patent/WO2011123066A8/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
    • G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
    • G01S5/0205—Details
    • G01S5/0221—Receivers

Definitions

  • Embodiments relate generally to devices for performing signal processing and signal processing methods.
  • embodiments relate to waveform recovery of ultra-wideband (UWB) radio frequency (RF) pulses for high precision ranging and positioning.
  • UWB ultra-wideband
  • RF radio frequency
  • the base station may be configured to determine the location of the mobile device based on the received radio frequency (RF) signals, e.g. UWB signals, transmitted from the mobile device.
  • RF radio frequency
  • UWB signals transmitted from the mobile device.
  • received radio frequency signals are sampled at high sampling rate.
  • the timing resolution may refer to the minimum time duration between two consecutive sampling points.
  • the cost goes up exponentially with higher sampling rate device, and more importantly, the sampling rate required may be way too fast and cannot be found in any existing commercial device.
  • Various embodiments provide a device for processing signals which solves at least partially the above mentioned problems.
  • a device for performing signal processing may include a receiver configured to receive a first periodic signal with a first pulse repetition frequency (PRF).
  • the device may further include a first generator configured to generate a second periodic signal with a second pulse repetition frequency being different from the first pulse repetition frequency.
  • the device may further include a second generator configured to generate a first delayed signal corresponding to the second periodic signal.
  • the device may further include a multiplier.
  • the multiplier may be configured to, during a first predetermined time period, multiply the first periodic signal and the second periodic signal to acquire an output signal.
  • the multiplier may be further configured to, during a second predetermined time period, multiply the first periodic signal and the first delayed periodic signal to acquire the output signal.
  • a signal processing method may include receiving a first periodic signal with a first pulse repetition frequency (PRF).
  • the method may further include generating a second periodic signal with a second pulse repetition frequency being different from the first pulse repetition frequency.
  • the method may further include generating a first delayed signal corresponding to the second periodic signal.
  • the method may further include, during a first predetermined time period, multiplying the first periodic signal and the second periodic signal to acquire an output signal.
  • the method may further include, during a second predetermined time period, multiplying the first periodic signal and the first delayed periodic signal to acquire the output signal.
  • FIG. 1 shows a communication system which includes a first radio
  • FIG. 2 (a) shows the waveforms of the received radio frequency (RF) signal, the local oscillator (LO) signal, the output signal from the mixer sampler, and the time expanded signal of the second radio communication device shown in FIG. 1 , respectively;
  • FIG. 2 (b) shows the waveforms of the received RF signal, the local oscillator signal, and the time expanded signal of the second radio communication device shown in FIG. 1 , respectively;
  • FIG. 3 shows a device for signal processing in one embodiment
  • FIG. 4 illustrates a signal processing method in one embodiment
  • FIG. 5 illustrates a communication system which includes a first radio communication device and a second radio communication device in one exemplary embodiment
  • FIG. 6 illustrates the output signal from the RF block in the second radio communication device shown in FIG. 1 and FIG. 5, the output signal from the pulse generator 1 13 in the second radio communication device shown in FIG. 1, the output signal 215 from the filter 115 in the time domain the second radio communication device shown in FIG. 1, the output signal 613 from the pulse generator 513 in the second radio communication device shown in FIG. 5, and the output signal from the filter 515 the second radio communication device shown in FIG. 5, respectively;
  • FIG. 7 illustrates a delay line in one exemplary embodiment
  • FIG. 8 (a) illustrates the waveform of the single local oscillator (LO) signal for the systems shown in FIG. 1 and FIG. 5;
  • FIG. 8 (b) illustrates the waveform of the single time expanded signal for the systems shown in FIG. 1 and FIG. 5;
  • FIG. 9 (a) illustrates the LO signals for the system shown in FIG. 1 ;
  • FIG. 9 (b) illustrates the LO signals for the system shown in FIG. 5;
  • FIG. 10 (a) illustrates the time expanded signals for the system shown in FIG. 1;
  • FIG. 10 (b) illustrates the time expanded signals for the system shown in FIG. 5;
  • FIG. 11 (a) illustrates an enlarged view of FIG. 10 (a).
  • FIG. 11 (b) illustrates an enlarged view of FIG. 10 (b). Description
  • the device as described herein may include a memory which is for example used in the processing carried out by the device.
  • a memory used in the embodiments may be a volatile memory, for example a DRAM (Dynamic Random Access Memory) or a non-volatile memory, for example a PROM (Programmable Read Only Memory), an EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), or a flash memory, e.g., a floating gate memory, a charge trapping memory, an MRAM (Magnetoresistive Random Access Memory) or a PCRAM (Phase Change Random Access Memory).
  • DRAM Dynamic Random Access Memory
  • PROM Programmable Read Only Memory
  • EPROM Erasable PROM
  • EEPROM Electrical Erasable PROM
  • flash memory e.g., a floating gate memory, a charge trapping memory, an MRAM (Magnetoresistive Random Access Memory) or a PCRAM (Phase Change Random Access Memory).
  • a “circuit” may be understood as any kind of a logic implementing entity, which may be special purpose circuitry or a processor executing software stored in a memory, firmware, or any combination thereof.
  • a “circuit” may be a hard-wired logic circuit or a programmable logic circuit such as a programmable processor, e.g. a microprocessor (e.g. a Complex
  • a “circuit” may also be a processor executing software, e.g. any kind of computer program, e.g. a computer program using a virtual machine code such as e.g. Java. Any other kind of implementation of the respective functions which will be described in more detail below may also be understood as a “circuit" in accordance with an alternative embodiment.
  • the time expansion sampling technique may be used at a receiver side when high timing resolution is needed in sampling periodic signals coming from a transmitter. For example, in the application of localization or positions, a higher sampling resolution may result in a more accurate location of an object.
  • a received signal consisting of or including repetitive waveforms may be expanded in time domain without changing the overall shape of the waveforms before the received signal is sampled by an analogue-to-digital circuit (ADC) for further processing.
  • ADC analogue-to-digital circuit
  • timing resolution without time expansion is 20 ns, with 10000 times time expansion of the received periodic signal, an equivalent timing resolution of 2 ps may be obtained.
  • the improvement in the timing resolution allows for a proportional
  • the pulse width is generally short in duration due to the very wide bandwidth.
  • the pulse repetition rate (PRR) or pulse repetition frequency (PRF) refers to the number of repetitive waveforms or pulses within one second duration of the signal. The main reason for using pulsed signals in an ultra-wideband (UWB) system.
  • the silent period between the waveforms allows for reflections or multipath signals to sufficiently settle down before the next pulse arrives at a receiver. This allows the direct signal from the transmitter to be differentiated from the reflected signals bouncing off nearby objects, hence mitigating the ill-effects of multipath on ranging or positioning accuracy.
  • the silent period between the waveforms becomes shorter as the PRF is increased.
  • Typical PRFs for localization applications for example range between 1 kHz to 100 MHz. So for example, in the case of a typical 20 MHz PRF and a 1 ns pulse width, the duty cycle is only 2%.
  • the normal time expanded waveform may give only one time expanded pulse per 500 ⁇ (50 ns x 10000).
  • the period of 500 may be referred to as the time expanded period in this context. This may cause any update that requires the time expanded waveform to be limited to 2 kHz, meaning, 2000 updates per second.
  • the pulse only spans 10 ⁇ (with 1 ns UWB pulse) with the rest of the 490 containing no useful information, it is generally felt that time is wasted on useless signal.
  • FIG. 1 illustrates a radio communication system 100 which applies time expansion technique.
  • the system 100 may include a first radio communication device 101 and a second radio communication device 102.
  • the first radio communication device 101 may be a mobile device.
  • the first radio communication device 101 may be a mobile device.
  • the first radio communication device 101 may be a mobile device.
  • the communication device may be configured to transmit a UWB signal with a first pulse repetition frequency (PRF), e.g. 20 MHz.
  • PRF pulse repetition frequency
  • the second radio communication device 102 may be a base station (BS) which is configured to receive the UWB signal transmitted by the mobile device 101.
  • the BS 102 may include an antenna 110 for receiving the UWB signal.
  • the BS 102 may further include a radio frequency (RF) block 11 1, consisting typically of front-end filters for rejecting unwanted signals and amplifiers for amplifying the wanted signal.
  • the BS 102 may further include a clock signal source 1 12 which is configured to generate a periodic signal.
  • the clock signal source 112 may generate a periodic signal with a second pulse repetition frequency, e.g. 19.998 MHz, for example.
  • the BS 102 may further include a pulse generator (i.e. sampling pulse generator) 113.
  • the output of the clock signal source 1 12 may be connected to the input of the pulse generator 113, such that the pulse generator 113 generates pulses at the same rate as the frequency of the input signal into the pulse generator 113.
  • a pulsed signal with a pulse repetition frequency of 19.998 MHz is generated from the pulse generator 113.
  • the signal output from the pulse generator 113 may be referred to as a local oscillator (LO) signal in this context.
  • the BS 102 may further include a mixer sampler 114.
  • the mixer sampler 114 may be configured to perform a multiplication operation of the output signal from the RF block 111 and the output signal of the pulse generator 113.
  • the BS 102 may further include an active filter 115 for filtering and amplifying the output signal of the mixer sampler 114.
  • the output signal from the filter 115 has the overall shape of waveforms of the received UWB signal but has been expanded in time domain.
  • the output signal from the filter 115 may be referred to as the time expanded signal in this context.
  • the time expanded signal may be further processed by an analogue-digital converter (ADC) (not shown) for sampling, and later sent to a field-programmable gate array (FPGA) (not shown) for further processing.
  • ADC analogue-digital converter
  • FPGA field-programmable gate array
  • the FPGA may be equipped with the knowledge of the time expanded waveform timing.
  • FIG. 2 (a) illustrates the waveforms of the received RF signal 211, the LO signal 213 (e.g. the output signal from the pulse generator (i.e. sampling pulse generator) 113), the output signal 214 from the mixer sampler 114, and the time expanded signal 215 (e.g. the output signal from the filter 115), respectively.
  • the RF signal 21 1 consists of a series of repetitive waveforms with a silent period between each two consecutive waveforms. The length of the silent period depends on the pulse duration (i.e. pulse width or waveform duration) tl and pulse to pulse period t2.
  • Each waveform 225 of the time expanded signal 215 has the shape of each waveform 221 of the received RF signal 211, but has been expanded in the time domain.
  • the expansion factor may depend on the values of the pulse repetition frequencies of the received RF signal and the LO signal.
  • the example values given herein are only for illustration purpose.
  • the RF signal 21 1 may correspond to a series of sinusoidal pulses or monocycles.
  • a waveform in this context may refer to any repetitive portion of the received signal such as the portion 221 in signal 211 shown in FIG. 2.
  • UWB refers to the use of a sufficiently narrow RF pulses with wide frequency bandwidths typically of at least 500 MHz.
  • the time expansion technique is however not limited to signal with any particular bandwidth or occupying any particular band of the electromagnetic frequency spectrum.
  • the type of RF pulse, the bandwidth and frequency spectrum used may be chosen by the user of the technique based on various conditions such as the regulatory requirements, the availability of frequency spectrum, the channel conditions, multipath environment, etc.
  • the use of 20 MHz for the PRF of the received signal and 19.998 MHz for the sampling pulse frequency is only illustrative.
  • the time expansion technique is independent of the PRF of the received signal, and the PRF used for the sampling signal may depend on the PRF of the received signal and the desired time expansion factor.
  • a corresponding 19.998 MHz may be used for the PRF of the sampling signal.
  • FIG. 2 (b) illustrates the output signal 211 from the RF block 11 1, the output signal 213 from the pulse generator 1 13, and the output signal 215 from the filter 115 in the time domain, respectively.
  • the pulse width of the RF signal received is 1 ns.
  • the resulted time expanded waveform i.e. the output signal of the filter 105, includes one time expanded pulse per 500 ⁇ (i.e. 50 ns x 10000).
  • Each time expanded pulse occupies a time span of 10 ⁇ followed by a silence period of 490 ⁇ as a consequence of time expanding the 49 ns of silent period between the pulses in the original signal.
  • Having more time expanded pulses per second can provide faster updates about the target/mobile device that is tracked by a radar/localization system.
  • One way to increase to the number of time expanded pulses per second or the update rate is to decrease the time expansion factor. But this will reduce the equivalent timing resolution which in turn will affect the ranging resolution.
  • Another conventional method is to increase the PRF.
  • Increasing PRF may lead to two problems.
  • the first problem arises when the signal power is limited by the regulatory authorities. With higher PRF, the amplitude of each pulse may have to be smaller in order to keep within the allowed power levels. Reducing the amplitude of the pulses would likely lead to a reduction in the maximum distance possible between the transmitter and receiver.
  • the other problem that could arise when the PRF is raised higher is that there will be less time for the multipath signals bouncing off nearby objects to settle down and so the multipath signals may overlap on the subsequent pulses arriving at the receiver, causing signal distortion.
  • FIG. 3 illustrates a device 300 for performing signal processing in one embodiment, and which may, when applying the time expansion technique, increase the update rate without sacrificing any other parameters.
  • the device 300 may include a receiver 301 which is configured to receive a first periodic signal with a first pulse repetition frequency.
  • the device 300 may further include a first generator 302 which is configured to generate a second periodic signal with a second pulse repetition frequency being different from the first pulse repetition frequency.
  • the device 300 may further include a second generator 303 which is configured to generate a first delayed signal corresponding to the second periodic signal.
  • the device 300 may further include a multiplier 304.
  • the multiplier 304 may be configured to, during a first predetermined time period, multiply the first periodic signal and the second periodic signal to acquire an output signal.
  • the multiplier 304 may be further configured to, during a second predetermined time period, multiply the first periodic signal and the first delayed periodic signal to acquire the output signal.
  • the receiver 301, the first generator 302, the second generator 303, the multiplier 304 may be coupled with each other, e.g. via an electrical connection 310 such as e.g. a cable or a computer bus or via any other suitable electrical connection to exchange electrical signals.
  • an electrical connection 310 such as e.g. a cable or a computer bus or via any other suitable electrical connection to exchange electrical signals.
  • the device 300 may be configured to receive the first periodic signal and to further process the first periodic signal.
  • the time expansion technique may be applied by the device 300. That is, the device 300 may be configured to first expand the received first periodic signal in the time domain and later use an analogue-to-digital converter (ADC) to sample the time expanded signal in order to achieve a higher timing resolution.
  • ADC an analogue-to-digital converter
  • the device 300 may generate a second periodic signal, and then sample the first periodic signal by the second periodic signal.
  • the sampling of the first periodic signal by the second periodic signal may be achieved by a multiplier which is configured to perform a multiplication operation of the first periodic signal and the second periodic signal.
  • the pulse repetition frequency of the second periodic signal may be different from the pulse repetition frequency of the first periodic signal, e.g. the pulse repetition frequency of the second periodic signal may be lower or higher than the pulse repetition frequency of the first periodic signal or the pulse repetition frequency of the second periodic signal may be higher than the pulse repetition frequency of the first periodic signal.
  • the pulse repetition frequency of the second periodic signal may be lower or higher than the pulse repetition frequency of the first periodic signal or the pulse repetition frequency of the second periodic signal may be higher than the pulse repetition frequency of the first periodic signal.
  • the first periodic signal may be sampled by a delayed periodic signal
  • the device 300 may be configured to generate a first delayed signal corresponding to the second periodic signal by the second generator 303.
  • the first periodic signal may be sampled by the second periodic signal such that at least one time expanded waveform is recovered.
  • the first periodic signal may be sampled by a first delayed signal that corresponds to the second periodic signal so as to recover at least one additional time expanded waveform.
  • the first periodic signal may include a plurality of waveforms.
  • Each waveform may have a first pulse width (or waveform duration), and there may be a timing interval between any two consecutive waveforms in the first periodic signal.
  • the first periodic signal may be a UWB signal that includes a plurality of pulses.
  • the first periodic signal may be the signal 211 as shown in FIG. 2 (a), which includes a plurality of waveforms 221, each waveform 221 having a first pulse width tl, and there is a timing interval 230 between any two consecutive waveforms 221.
  • the second periodic signal may include a plurality of waveforms. Each waveform may have a second pulse width, and there may be a timing interval between any two consecutive waveforms.
  • the second periodic signal may include a plurality of pulses.
  • the second periodic signal may be the signal 213 as shown in FIG. 2 (a), which includes a plurality of pulses 223, each waveform 223 of the signal 213 having a second pulse width t3, and there is a timing interval 231 between any two consecutive waveforms 223.
  • each waveform of the second periodic signal may be or may include a pulse.
  • the second pulse width is shorter than the first pulse width.
  • the first pulse width tl is longer than the second pulse width t3.
  • the first pulse width, tl, as illustrated in Fig. 2(a) may be shorter than the second pulse width t3.
  • the first pulse width tl may be the same as the second pulse width t3.
  • the second pulse width t3, illustrated in Fig. 2(a) may be so long that the periodic waveforms 223 follow one after another in time, with no time duration between the completion of one waveform and the start of the next waveform, effectively making signal 213 a continuous but periodic signal with no breaks between the waveforms.
  • the second pulse repetition frequency is lower than the first pulse repetition frequency. In an alternative embodiment, the second pulse repetition frequency is higher than the first pulse repetition frequency.
  • the first delayed signal may correspond to the second periodic signal delayed by a predetermined delay.
  • the predetermined delay may be selected from a plurality of selectable delays. The predetermined delay may be set in such a way that, at least one additional time expanded waveform resulted from the sampling of the first periodic signal by the first delayed signal may be recovered between the recovery of two consecutive time expanded waveforms resulted from the sampling of the first periodic signal by the second periodic signal.
  • the multiplier 304 may be configured to, during a third predetermined period, multiply the first periodic signal and the second periodic signal to acquire the output signal. In other words, after at least one time expanded waveform resulted from the sampling of the first periodic signal by the first delayed signal is recovered , a time expanded waveform resulted from the sampling of the first periodic signal by the second periodic signal may be recovered.
  • the device 300 may further include a third generator 305 which is configured to generate a second delayed signal corresponding to the second periodic signal.
  • the receiver 301, the first generator 302, the second generator 303, the multiplier 304 and the third generator 305 may be coupled with each other, e.g. via the electrical connection 310.
  • the multiplier 304 may be configured to, during a fourth predetermined time period, multiply the first periodic signal and the second delayed periodic signal to acquire the output signal. For example, after the recovery of at least one time expanded waveform resulted from the sampling of the first periodic signal by the first delayed signal, at least one time expanded waveform resulted from the sampling of the first periodic signal by the second delayed signal may be recovered.
  • the second predetermined time period starts after the first predetermined time period.
  • the first predetermined time period may be preset in such a way that the sampling of the first periodic signal by the second periodic signal may enable the recovery of at least one time expanded waveform, and after the first predetermined time period, and during the second predetermined time period, the sampling of the first periodic signal by the first delayed signal may begin for the recovery of a further time expanded waveform.
  • the first pulse repetition frequency and the second pulse repetition frequency are selected from a frequency range between 1 kHz and 100 MHz.
  • the first pulse repetition frequency is 20 MHz.
  • the second pulse repetition frequency is 19.998 MHz. It is however noted that the range of frequencies between 1 kHz and 100 MHz is not limited thereto. In actual fact, the frequency range may depend on the application and poses no direct limitation on the proposed time expansion technique.
  • the output signal includes a first output waveform during the first predetermined time period. In a further embodiment, the first output waveform may include a pulse. During the first predetermined time period, the first periodic signal is sampled by the second periodic signal.
  • Such sampling may be realized by the multiplier 304 which is configured to perform a multiplication operation of the first periodic signal and the second periodic signal.
  • the output of the multiplier 304 may include a plurality of waveforms like the signal 214 shown in FIG. 2 (a) which include a plurality of pulses. This plurality of waveforms may be further filtered such that a time expanded waveform like the waveform 225 shown in FIG. 2 (a) may be obtained as an output waveform.
  • the output signal includes a second output waveform during the second predetermined time period.
  • the second output waveform may include a pulse.
  • the first periodic signal is sampled by the first delayed signal which corresponds to the second periodic signal delayed by a predetermined delay.
  • the output of the multiplier 304 may include a plurality of waveforms like the signal 214 shown in FIG. 2 (a) which include a plurality of pulses. This plurality of waveforms may be further filtered such that a time expanded waveform like the waveform 225 shown in FIG. 2 (a) may be obtained as an output waveform.
  • FIG. 4 shows flow diagram 400 illustrating a signal processing method according to one embodiment. The signal processing method as described herein may correspond to the device 300 as described above.
  • a first periodic signal with a first pulse repetition frequency is received.
  • a second periodic signal with a second pulse repetition frequency being different from the first pulse repetition frequency is generated.
  • a first delayed signal corresponding to the second periodic signal is generated.
  • the first periodic signal and the second periodic signal are multiplied to acquire an output signal.
  • the first periodic signal and the first delayed periodic signal are multiplied to acquire the output signal.
  • the first periodic signal may include a plurality of waveforms, each waveform having a first pulse width, and there is a timing interval between any two consecutive waveforms.
  • the second periodic signal may include a plurality of waveforms, each waveform having a second pulse width, and there is a timing interval between any two consecutive waveforms.
  • each waveform of the second periodic signal may be or may include a pulse.
  • the second pulse width is shorter than or longer than or the same as the first pulse width.
  • the second pulse repetition frequency is lower or higher than the first pulse repetition frequency.
  • the first delayed signal corresponds to the second periodic signal delayed by a pre-determined delay.
  • the pre-determined delay is selected from a plurality of selectable delays.
  • the method may include during a third predetermined time period, multiplying the first periodic signal and the second periodic signal to acquire the output signal.
  • the method may include generating a second delayed signal corresponding to the second periodic signal, and during a fourth predetermined time period, multiplying the first periodic signal and the second delayed periodic signal to acquire the output signal.
  • the second predetermined time period starts after the first predetermined time period.
  • the first pulse repetition frequency and the second pulse repetition frequency are selected from a frequency range between 1 kHz and 100 MHz. In one exemplary embodiment, the first pulse repetition frequency is 20 MHz. In one exemplary embodiment, the second pulse repetition frequency is 19.998 MHz.
  • the output signal may include a first output waveform during the first predetermined time period.
  • the first output waveform includes a pulse.
  • the output signal includes a second output waveform during the second predetermined time period.
  • the second output waveform may include a pulse.
  • FIG. 5 illustrates a radio communication system 500 which includes a first communication device 501 and a second communication device 502 according to one exemplary embodiment.
  • the first communication device 501 may be a mobile device and the second communication device 502 may be a base station (BS).
  • the BS 502 may be configured to receive radio frequency signals from the mobile device 501, for example.
  • the mobile device 501 may be configured to transmit a UWB signal with a first pulse repetition frequency (PRF), for example 20 MHz.
  • the BS 502 may be configured to receive the UWB signal transmitted by the mobile device 501.
  • the BS 502 may include an antenna 510 for receiving the UWB signal.
  • the BS 502 may further include a radio frequency (RF) block 511, consisting typically of front-end filters for rejecting unwanted signals and amplifiers for amplifying the wanted signal.
  • the BS 502 may further include a clock signal source 512 which is configured to generate a periodic signal.
  • the clock signal source 512 may generate square wave or sinusoidal wave or any other periodic signal with a second pulse repetition frequency, for example, at 19.998 MHz.
  • the BS 502 may further include a delay line 520 which receives the output signal from the clock signal source 512.
  • the delay line generally refers to a component that delays a signal by a certain amount of time.
  • the delay line 520 may for example be a typical 'tapped delay line integrated circuit (IC)' which has various outputs where the input signal can be tapped out with various delays.
  • IC integrated circuit
  • An example of such an IC is the DS1100Z series of delay lines from MAXIM.
  • the tapped delay line and external switch may be replaced by a programmable delay line IC.
  • An example of a programmable delay line IC that may be used is DS1123L from MAXIM.
  • the delay line 520 may be configured to delay the output signal of the clock signal source 512 by a predetermined delay, e.g. 20 ns.
  • the BS 502 may further include a switch 521 and a pulse generator 513.
  • the switch 521 may be a single-pole double-throw (SPDT) switch, for example.
  • the single pole of the switch 521 may be connected to the input of the pulse generator 513.
  • a first terminal (or throw) 531 of the switch 521 may be electrically connected to an output 541 of the delay line 520 which is configured to output a first delayed signal of the input signal into the delay line 520, wherein the first delayed signal may correspond to the input signal into the delay line 520 delayed by a first
  • a second terminal (or throw) 532 of the switch 521 may be connected to an output 542 of the delay line 520 which is configured to output a second delayed signal corresponding to the input signal into the delay line 520 delayed by a second predetermined delay.
  • the second predetermined delay may be different from the first predetermined delay, such that the second delayed signal may correspond to the first delayed signal delayed by a predetermined delay. Accordingly, when the single pole of the switch 521 is connected to the first terminal 531, the first delayed signal from the clock signal source 512 is input into the pulse generator 513. When the single pole of the switch 521 is connected to the second terminal 532, the second delayed signal corresponding to the signal from the clock signal source 512 delayed by a second predetermined delay is input into the pulse generator 513.
  • the pulse generator 513 is configured to output pulses at a second pulse repetition frequency of 19.998 MHz with a first predetermined delay or a second predetermined delay depending on the connection of the switch 521.
  • the control of the switch 521 may be via a field-programmable gate array (FPGA) (not shown).
  • the signal output from the pulse generator 513 may be referred to as a local oscillator (LO) signal in this context.
  • the BS 502 may further include a mixer sampler 514.
  • the mixer sampler 514 may be configured to perform a multiplication operation of the output signal from the RF block 511 and the output signal of the pulse generator 513.
  • the BS 502 may further include a filter 515, e.g. an active filter, for filtering the output signal of the mixer sampler 514.
  • the output signal from the filter 515 may have the overall shape of waveforms of the received UWB signal but has been expanded in the time domain.
  • the output signal from the filter 515 may be referred to as the time expanded signal in this context.
  • the time expanded signal may be further processed by an analogue-digital converter (ADC) (not shown) for sampling, and later sent to the field-programmable gate array (FPGA) for processing.
  • ADC analogue-digital converter
  • FPGA field-programmable gate array
  • the FPGA may be equipped with the knowledge of the time expanded waveform timing and thus perform the control of the switch 521.
  • the FPGA may toggle the SPDT switch 521.
  • the LO signal output from the pulse generator 513 may be then delayed by, for example, 20 ns or 40 ns, causing the LO signals to arrive 20 ns or 30 ns earlier in the mixer sampler 514.
  • the LO signal from the pulse generator 513 may be controlled so that time containing the silence period at the output end of the mixer sampler 514 may be skipped.
  • the delay of the LO signal may be controlled via switching the delay of the clock signal source 512.
  • the usage of the delay line 520 and the switch 521 does not involve high frequency RF components, thus the circuitry is simple and cheap.
  • the switch 521 may not be limited to a SPDT switch, and may be a single-pole multi-throw switch, for example. The pole may be switched to be connected with more than two outputs of the delay line 520 in the device 502.
  • the output 541 of the delay line 520 may be connected to the input of the pulse generator 513; during a second predetermined time period, the output 542 of the delay line 520 may be connected to the input of the pulse generator 513; during a third predetermined time period, the output 543 of the delay line 520 may be connected to the input of the pulse generator 513; and during a fourth predetermined time period, the output 541 of the delay line 520 may be connected to the input of the pulse generator 513, and so on.
  • the switch 521 and the delay line 520 may be replaced by a programmable delay line.
  • the programmable delay line may be configured to delay the clock signal by a time period that is controlled by the FPGA.
  • FIG. 6 illustrates the output signal 211 from the RF block 111 in the device 102 shown in FIG. 1, the output signal 213 from the pulse generator 113 in the device 102 shown in FIG. 1, the output signal 215 from the filter 115 in the time domain in the device 102 shown in FIG. 1, the output signal 613 from the pulse generator 513 in the device 502 shown in FIG. 5, and the output signal from the filter 515 in the device 502 shown in FIG. 5, respectively.
  • the pulse width of the RF signal received is assumed to be 1 ns for illustration purpose.
  • the sampling of the RF signal 211 by the LO signal 213 may lead to the recovery of time expanded waveforms 250, 252, etc.
  • the delay of the LO signal in the device 502 may be switched to avoid the time when no RF pulse is present at the output of the mixer sampler 514, thereby raising the efficiency. That is, for example, the pulses of the LO signal 613 during time period Ta in the LO signal 613 may be identical with those in the LO signal 213.
  • the sampling of the RF signal 211 by the LO signal 213 or 613 during time period Ta may lead to the recovery of a time expanded waveform 250 in signal 215 or a time expanded waveform 650 in signal 615, wherein the waveforms 250 and 650 are identical.
  • the LO signal 613 may be delayed by a predetermined delay as shown in the circled portion 660. Consequently, the time when no RF pulse is present at the output of the mixer sampler 514 may be skipped.
  • the sampling of the RF signal 211 by the delayed LO signal 613 during time period Tb may lead to the recovery of another time expanded waveform 651.
  • the delayed LO signal 613 may be restored in order to recover a next time expanded signal 652 which corresponds to the time expanded signal 252.
  • the time expanded waveform i.e. the signal 615, which may be realized with time delay control of the clock signal (or sampling signal or LO) as illustrated in FIG. 5, has double waveform information in comparison to the time expanded waveform, i.e. the signal 215, without time delay control.
  • the amount of waveform may be increased multiple times depending on the amount of the delay and switches.
  • the update rate may be increased without sacrificing any other parameters.
  • FIG. 7 illustrates a delay line 700 which may be used in the second communication device 502 shown in FIG. 5 according to one exemplary embodiment.
  • a signal may be input to the input 701 of the delay line 700.
  • the delay line 700 may have several outputs each outputting a delayed signal corresponding the input signal by a predetermined delay.
  • there may be a first output 702, a second output 703, a third output 704, a fourth output 705, and a fifth output 706.
  • signal output from the first output 702 may be a delayed signal corresponding to the input signal delayed by 20 ns.
  • Signal output from the second output 703 may be a delayed signal corresponding to the input signal delayed by 40 ns.
  • Signal output from the third output 704 may be a delayed signal corresponding to the input signal delayed by a further 20 ns, and so on.
  • predetermined delay is only for illustration purpose and is not limited thereto. Depending on the specific application requirement, any suitable predetermined delay may be selected.
  • the input 701 of the delay line 700 may be connected to the output of the clock signal source 512
  • the first output 702 of the delay line 700 may be connected to the first terminal 531 of the switch 521
  • the second output 703 of the delay line 700 may be connected to the second terminal 532 of the switch 521.
  • the output of the clock signal source 512 may be connected to both the input 701 of the delay line and the first terminal 531 of the switch 521
  • the first output 702 of the delay line 700 may be connected to the second terminal 532 of the switch 521.
  • connection of the clock signal source, the delay line, and the switch as described herewith is only for illustrative purpose and there may be numerous variations to the arrangement, the connections, and the type of delay lines and switches used depending on the specific requirement of the application.
  • the switch and the delay line as illustrated in FIG. 5 may not affect the waveform of the LO pulse output from the pulse generator 513.
  • the single LO pulse is the same for both devices 102 and 502 (with or without switching).
  • the single time expanded pulse is the same for both devices 102 and 502.
  • FIG. 8 (a) illustrates single LO pulse for both devices 102 and 502.
  • FIG. 8 (b) illustrates the single time expanded pulse for devices 102 and 502.
  • FIG. 9 (a) shows the LO signal in device 102 without switching.
  • the LO signal has constant ⁇ 50 ns in between the pulses (because of the 19.998MHz pulse repetition rate); whereas as shown in FIG. 9 (b), even though the LO signal in device 502 with switching has also 19.998 MHz pulse repetition rate, the time between each pulse is occasionally 20 ns or 30 ns when the switch is toggled.
  • FIG. 10 (a) shows the time expanded signal for device 102 without switching.
  • the normal time expanded waveform give only one time-expanded pulse per 500us (i.e. 20 pulses in 10 ms).
  • FIG. 10 (b) shows the time expanded signal for device 502 with delay control.
  • the time expanded signal gives 40 pulses in 10 ms, equivalent to double the pulse rate.
  • FIG. 11 shows a close-up view of FIG. 10.
  • FIG. 1 1 (a) illustrates a graphical plot for device 102 without switching
  • FIG. 11 (b) shows the result for device 502 with delay control.
  • the delay line 520 is set to provide 20 ns delay and 40 ns at two outputs of the delay line 520, and the pulse is either 200 ⁇ or 300 ⁇ (500 ⁇ minus 200 ⁇ ) away from the next pulse.
  • a time expanded waveform 1101 is recovered every 500 ⁇ .
  • each recovered time expanded waveform 1102 may correspond to a waveform 1 101 in FIG. 11 (a).
  • Additional time expanded waveforms 1103 may be recovered as a result of the delay of the LO signal, e.g. 613.
  • a method of waveform recovery of repetitive signals is provided. More particularly, according to various embodiment, for the recovery of UWB pulses at a receiver side (e.g. at a BS), the quiet or silent periods during which the multiplier (or mixer sampler) outputs no useful signal, may be shortened or even completely skipped by delaying the sampling instances of the LO signals, which advantageously permits more waveforms or pulses to be recovered in a given time from equivalent time sampling.
  • a system of waveform recovery according to various embodiments of the invention is also provided.
  • the method of controlled delay of sampling pulses in the LO signal includes delaying sampling pulse after a full recovery of one time expanded waveform such that at least an addition time expanded waveform may be recovered.
  • the original time expanded waveform per time expanded period may be recovered.
  • the delay of the sampling pulse at least twice the number of recovered time expanded waveforms may be obtained.
  • a simple digital delay circuit such as a tapped delay line IC, may be used to achieve the controlled delay, and to improve the efficiency of the waveform sampling technique where more waveforms may be recovered compared to conventional time expansion receiver systems such as that illustrated in FIG. 1.
  • the simple delay circuit can be of low cost and complexity.
  • the device for performing signal processing and signal processing method as described herein may be implemented in a similar fashion by delaying the first periodic signal (e.g. received RF signal). That is, instead of generating a delayed signal corresonding to the second periodic signal, a delayed signal correspodning to the first periodic signal (e.g. the RF signal) may be generated.
  • the RF signal which is generally from higher frequency bands, will need high frequency components/parts to delay the RF signal.
  • delaying the clock signal source for the second periodic signal which is generally of lower frequency spectrum, only low frequency components/parts are needed.
  • a programmable delay circuit is provided to achieve the controlled delay, and to improve the efficiency of the waveform sampling technique where more waveforms may be recovered compared to conventional time expansion receiver systems such as that illustrated in FIG. 1.
  • the programmable delay circuit can be of low cost and complexity.
  • the controlled delay may be implemented using a programmable IC instead of the switch and tapped delay line IC combination.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Abstract

Dans divers modes de réalisation, cette invention concerne un dispositif de traitement de signaux. Ce dispositif comprend ; un récepteur conçu pour recevoir un premier signal périodique selon une première fréquence de répétition d'impulsions ; une première génératrice conçue pour générer un second signal périodique selon une seconde fréquence de répétition d'impulsions qui est différente de la première fréquence de répétition d'impulsions ; une seconde génératrice conçue pour générer un signal différé correspondant au second signal périodique ; et un multiplicateur dont la fonction consiste, pendant un premier laps de temps prédéterminé, à multiplier le premier signal périodique et le second signal périodique pour acquérir un signal de sortie, et, pendant un second laps de temps prédéterminé, à multiplier le premier signal périodique et le premier signal périodique différé, pour acquérir le signal de sortie.
PCT/SG2011/000131 2010-03-30 2011-03-30 Dispositif et procédé de traitement de signaux faisant intervenir une technique d'expansion temporelle WO2011123066A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
SG2012071452A SG184278A1 (en) 2010-03-30 2011-03-30 A device for performing signal processing and a signal processing method which applies time expansion technique

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SG201002196 2010-03-30
SG201002196-2 2010-03-30

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4521778A (en) * 1981-02-27 1985-06-04 Dornier System Gmbh High-resolution, coherent pulse radar
US5701006A (en) * 1995-11-21 1997-12-23 Simula Inc. Method and apparatus for measuring distances using fiber optics
US20090085799A1 (en) * 2007-09-28 2009-04-02 Gabriel Serban Pulse radar system
US20090189800A1 (en) * 2007-12-06 2009-07-30 Uri Benari Pulse radar ranging system
US20100019953A1 (en) * 2008-07-28 2010-01-28 George Burcea Pulse Radar Ranging System

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4521778A (en) * 1981-02-27 1985-06-04 Dornier System Gmbh High-resolution, coherent pulse radar
US5701006A (en) * 1995-11-21 1997-12-23 Simula Inc. Method and apparatus for measuring distances using fiber optics
US20090085799A1 (en) * 2007-09-28 2009-04-02 Gabriel Serban Pulse radar system
US20090189800A1 (en) * 2007-12-06 2009-07-30 Uri Benari Pulse radar ranging system
US20100019953A1 (en) * 2008-07-28 2010-01-28 George Burcea Pulse Radar Ranging System

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