Periodic binary codes with zero and small time sidelobe levels

Shinriki, Masanori; Takase, Hiroshi; Susaki, Hironori

doi:10.1049/ip-rsn:20050150

Cited by 5 publications

(5 citation statements)

References 2 publications

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“…The code self-noise makes it harder to detect the weaker echoes from smaller targets, thereby limiting the dynamic range of the radar system utilizing such waveforms. Different techniques have been proposed to minimize the SLL; these include windowing [22,23], coding [24][25][26][27], mismatched filtering [28][29][30][31][32][33][34], and others [35,36], including waveform design [37][38][39][40][41][42]. In this latter group, we can include the Golay code pairs with null levels of SSL and ISL; however, despite of the advantages provided by the use of these code pairs, its use requires the transmission and reception of two single sequences instead of one [40] slowing down the response time of the systems.…”

Section: Applicabilitymentioning

confidence: 99%

Extended Optimal Filters for Adaptive-Ontransmit Radar Systems Using Binary Codes

Alejos¹,

Dawood²,

Sánchez³

2012

PIER

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Abstract-This study introduces an extended optimal filtering technique for adaptive-on-transmit radar based on the transmission of pseudorandom noise waveforms as a method to simultaneously achieve low sidelobe level and spectral purity without degrading the main peak of the cross-correlation function. The proposed method is an extended version of the classical optimal filtering technique, resulting in longer codes with three simultaneously improved features that usually work in trade-off: 1) the cross-correlation function (CCF) sidelobe level is reduced in direct proportion to the filter length, K ; 2) the out-ofband spectral suppression is at least 40 dB for pseudorandom binary sequences (PRBS); and 3) the frequency spectrum tail presents a decay given by K −4 , offering larger out-of-band frequency suppression. The proposed technique provides skew-symmetry to the input signal and is tested on PRBS, Barker, and Golay pair of complementary codes. The proposed codes are also demonstrated to be Doppler resistant and offer better multipath capability.

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Section: Applicabilitymentioning

confidence: 99%

Extended Optimal Filters for Adaptive-Ontransmit Radar Systems Using Binary Codes

Alejos¹,

Dawood²,

Sánchez³

2012

PIER

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“…Table 1 shows some examples of the proposed binary codes in a range of code lengths less than 60, and their compression ratios (CR) and Sp/Mp ratios, where Sp is the peak level of the sidelobe and Mp is the peak level of the mainlobe. The compression ratio (CR) is approximately defined as the ratio of the pulse width before compression to the compressed pulse width, which is determined by the width between two points on the half-peak magnitude of the autocorrelation function [9,10]. The Sp/Mp ratio for code no.…”

Section: Compression Ratio and S P /M P Ratio For Proposed Binarmentioning

confidence: 99%

“…Sato et al indicated that the PSLs of the new polyphase codes could be smaller than the conventional limit [8]. Shinriki et al proposed periodic binary codes with zero and small PSLs [9].…”

Section: Introductionmentioning

confidence: 99%

Properties of binary codes compressed to several subpulses

Takase

Shinriki

2011

2011 IEEE International Conference on Microwaves, Communications, Antennas and Electronic Systems (COMCAS 2011)

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New binary codes that compress a pulse to a width of several subpulses are proposed. The proposed binary codes are surveyed by computers up to code length 60. It is found that the peak-sidelobe to peak-mainlobe ratio for the proposed binary codes is smaller than that of conventional binary codes. Furthermore, the bandwidth characteristic and the Doppler characteristic for the proposed binary codes are evaluated. As a result, we have confirmed that characteristics of the proposed binary codes are better than those of the conventional codes.

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“…The Hadamard transform uses the m‐sequence to modulate the ion gate, and, from a mathematical point of view, the autocorrelation function of the m‐sequence itself has a constant coefficient of −1, which was attributed to a side lobe, 32 although the generally used s‐matrices transform neglected this constant coefficient by replacing −1 with 0. A sequence with out‐of‐phase autocorrelation coefficients are zeros with only one in‐phase autocorrelation coefficient corresponding to the output of autocorrelation, and this should reduce artifact peaks and hence improve the S/N ratios of IMS spectra.…”

Section: Introductionmentioning

confidence: 99%

“…Although much effort has been made to detect or improve the spectra quality such as using an extended m-sequence, the HT-IMS spectra may still suffer from annoying artificial peaks, and many processing techniques have been developed to address this problem. [28][29][30][31] The Hadamard transform uses the m-sequence to modulate the ion gate, and, from a mathematical point of view, the autocorrelation function of the m-sequence itself has a constant coefficient of À1, which was attributed to a side lobe, 32 although the generally used smatrices transform neglected this constant coefficient by replacing À1 with 0. A sequence with out-of-phase autocorrelation coefficients are zeros with only one in-phase autocorrelation coefficient corresponding to the output of autocorrelation, and this should reduce artifact peaks and hence improve the S/N ratios of IMS spectra.…”

Section: Introductionmentioning

confidence: 99%

Almost perfect sequence modulated multiplexing ion mobility spectrometry

Qing

Zhang

et al. 2022

Rapid Comm Mass Spectrometry

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Rationale Multiplexing ion mobility spectrometry with multiple ion injection pulses was used to achieve a high duty cycle and thus improve the signal‐to‐noise (S/N) ratio while maintaining high resolving power compared with the traditional single‐pulse signal averaging method. Historically, an ion mobility spectrum was reconstructed by various multiplexing methods including Fourier transform ion mobility spectrometry (FT‐IMS), Hadamard transform ion mobility spectrometry (HT‐IMS), and linear frequency modulation correlation ion mobility spectrometry (LFM‐CIMS) sequence or Barker code. Methods To achieve an artifact‐free multiplexing ion mobility spectrum, an almost perfect sequence (APS) with correlation technique was proposed to modulate the Bradbury‐Nielson ion gate and was compared with FT‐IMS, HT‐IMS, LFM‐IMS, and the traditional single‐pulse signal averaging method. Results Experimental results showed that there are no artifact peaks in the APS‐IMS spectra except an inverted mirror peak, and the S/N ratio was improved 5–8 times with a repetition time of 40–60 ms, corresponding to the improvement in the duty cycle. With the same duty cycle and similar acquisition time, APS‐IMS showed a higher S/N ratio than HT‐IMS for its unique autocorrelation response. Conclusions The APS‐IMS technique offered a higher duty cycle and relatively shorter modulation period compared with reported multiplexing methods and is suitable to track rapidly changing signals without losing information and adding extra transformation artifact peaks.

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Periodic binary codes with zero and small time sidelobe levels

Cited by 5 publications

References 2 publications

Extended Optimal Filters for Adaptive-Ontransmit Radar Systems Using Binary Codes

Extended Optimal Filters for Adaptive-Ontransmit Radar Systems Using Binary Codes

Properties of binary codes compressed to several subpulses

Almost perfect sequence modulated multiplexing ion mobility spectrometry

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