US3680007A - Surface wave transducer for digital signals - Google Patents

Surface wave transducer for digital signals Download PDF

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Publication number
US3680007A
US3680007A US76942A US3680007DA US3680007A US 3680007 A US3680007 A US 3680007A US 76942 A US76942 A US 76942A US 3680007D A US3680007D A US 3680007DA US 3680007 A US3680007 A US 3680007A
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United States
Prior art keywords
parallel
transducer
leads
interdigital transducer
lead
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Expired - Lifetime
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US76942A
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English (en)
Inventor
Samuel Chin-Chong Tseng
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International Business Machines Corp
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International Business Machines Corp
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
    • H03H9/14544—Transducers of particular shape or position
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
    • H03H9/14544—Transducers of particular shape or position
    • H03H9/14547—Fan shaped; Tilted; Shifted; Slanted; Tapered; Arched; Stepped finger transducers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
    • H03H9/14544—Transducers of particular shape or position
    • H03H9/1455—Transducers of particular shape or position constituted of N parallel or series transducers

Definitions

  • ABSTRACT [52] US. Cl. ..333/30 R, 3 l0/9.8 S f wave transducers f the i t di iufl type for generab [51] Int. Cl. ..H03h 7/30 ing and detecting return m zero pulse sequences of surface Fidd Search "333/701 30 R; 310/82 waves are disclosed.
  • the transducer which is located on the 343/17'2 surface ofa suitable surface wave medium, is an interdigitated electrode array including main electrodes that are perpen- [56] Reterences cued dicular to the transducer leads and auxiliary electrodes that UNITED STATES PATENTS are inclined at an angle to the main electrodes.
  • the present invention is in the field of surface wave electronics, and, more particularly, relates to an interdigital transducer for surface wave generation and detection.
  • FIG. 12 of the article shows the prior art transducer which differs from the present invention in that it employs only perpendicular electrodes and does not generate and detect return to zero pulse sequences. Furthermore, in the three electrode transducer described in the prior art, the center finger takes the entire load current of the device, and is very easily overloaded.
  • An object of the present invention is to provide a transducer for generating and detecting surface waves.
  • Another object of the present invention is to provide a transducer for generating and detecting return to zero binary sequences of surface waves.
  • a further object of the present invention is to provide an interdigitated surface wave transducer having auxiliary electrodes.
  • Surface waves are elastic waves which are propagated predominantly on the free surface of a solid.
  • Surface wave electronics are significant since the surface waves are accessible along their entire length and are compatible with integrated circuit technology. Surface waves can be channeled, sensed, focused, mixed, amplified and otherwise employed in signal processing.
  • the interdigital transducer includes a lead having a plurality of electrodes, also referred to as fingers, extending perpendicularly from the lead.
  • the characteristics of the generated surface wave depend on the number of fingers and their spacing.
  • the conventional interdigital surface wave transducer with more than two fingers, can be used to process radio frequency pulses but not video pulses. This is because the transducer itself is a band-pass filter with finite bandwidth about a resonance frequency, and the bandwidth is inversely proportional to the number of fingers.
  • coding theory has been used such as the Barker Code and the Golay Code.
  • surface wave pulse train is represented by two digit complementary sequences (+1, +1) and (+1, 1).
  • the autocorrelation functions of these sequences are, respectively (+1, +2, +1) and (l, +2, 1
  • the sum of the two autocorrelation functions is the output sequence (0, +4,
  • the advantage of this type of coding is seen from the fact that the complementary sequence input signals have digits with one unit of amplitude, while the output signal has a digit with four units of amplitude at the center and zero elsewhere. Thus, the output has a four-times-better signal to noise ratio than the input acoustic wave pulse train.
  • two transducers 10 and 12 are located on substrate 14 having the two complementary surface wave pulse sequences 16 and 18 propagated thereon.
  • Pulse sequence 161s the (+1, +1) and sequence 18 is the (+1, I
  • the transducer performs the autocorrelation function to produce the (+1, +2, +1) sequence 20.
  • transducer 12 receives sequence 18 and autocorrelates to produce the (-l, +2, --1 sequence 22.
  • the sequence (0, +4, 0) results, which is the single pulse 24.
  • the transducers function as detectors of the return-to-zero sequences 16 and 18;
  • FIG. 2 another pair of transducers 26 and 28 are added to the structure of FIG. 1 to function as generators of the complementary sequences.
  • Transducers 26 and 28 receive the video pulse 30 as an input and generate sequences 16 and 18.
  • the code sequences are in return-tozero form, which is the manner in which the code is meant to be used.
  • the first code sequence is generated as a sequence of two sine waves, which has a polarity of (+1, l, +1, I); and the first and third elements are used to represent the sequence.
  • the second sequence is represented by a sine wave and a cosine wave, which has a polarity (+1, 1 l +1 and the first and third elements are used to represent the sequence.
  • Such prior art systems have the disadvantage that the transducer generators must be connected to a balanced source, and the transducer detectors must be connected to a balanced load to assure complete cancellation at the output.
  • FIG. 3 an embodiment of the structure of an interdigital transducer for generating and detecting the returnto-zero surface wave signals is shown.
  • a first auxiliary electrode 46 is connected at an angle to main electrode 42
  • a second auxiliary electrode 48 is connected at an angle to main electrode 38 such that auxiliary electrodes 46 and 48 are parallel.
  • the auxiliary electrodes are shown connected to main electrodes, they need not be connected and may just be located in the region between the two leads. Referring to FIG. 4, the pulse sequence produced by transducer 32 is depicted. If there were no auxiliary electrodes, the positive pulses would be produced by the finger pairs 36 and 42 and 38 and 44.
  • the negative pulse depicted by the dotted line would be produced by electrode pair 38 and 42.
  • the dotted line negative pulse is not present; and, instead, a pulse is produced by the auxiliary electrode pair 46 and 48, which propagates ofi" in a different direction from the position pulses thereby achieving the (+1, +1) sequence.
  • the pulse generated by the auxiliary electrodes 46 and 48 will propagate in a direction perpendicular to the electrodes, and will not be intercepted by receiving transducer 64.
  • the other generating transducer operates in a similar manner except that electrode pair 50 and 52 produce a positive pulse, and electrode pair 54 and 56 produce a negative pulse.
  • Main electrodes 52 and 54 are connected to the same lead and should be at the same potential and will, therefore, not produce a pulse. Theoretically, then auxiliary electrodes 58 and 60 are not required.
  • the electric field between the electrodes 52 and 54 may not be zero (the line integral of the field from 52 to 54 is zero) and may produce a small pulse, which will be positive or negative depending on whether electrode 52 is positive or negative with respect to electrode 54.
  • auxiliary electrodes 58 and 60 are included to propagate the small pulses in a different direction.
  • the (+1, +1) sequence is detected by transducer 62 to produce a (+1, +2, +1 sequence
  • the (+1, l) sequence is detected by transducer 78 to produce a (l, +2, 1) sequence as illustrated in FIG. 2.
  • the first positive pulse hits electrode 64, which produces a positive pulse (+1) on the upper lead 64 when the first surface wave pulse is between main electrodes 64 and 66.
  • the first positive surface wave pulse reaches the region between electrodes 68 and 70, it again produces a positive pulse on lead 65.
  • the second positive surface wave pulse of the sequence has reached electrode 64 and also produces a positive pulse on lead 65.
  • the two simultaneous positive pulses add together (+2).
  • the second positive pulse of the sequence reaches electrode 68 to produce a positive pulse on lead 65 (+1).
  • the total output sequence on lead 65 is therefore (+l,+2,+l).
  • the first negative pulse reaches electrode 80 to produce a negative pulse on lead 81 1).
  • the negative pulse reaches electrode 86, it makes electrode 86 negative with respect to lead 88, which produces a positive pulse on lead 81.
  • the second pulse of the sequence which is positive, reaches lead 80 and also produces a positive pulse on lead 81.
  • the two positive pulses add together (+2).
  • the second (positive) pulse of the sequence reaches electrode 86. Electrode 86 becomes positive relative to electrode 88, which produces a negative pulse on lead 81 (l).
  • the total output sequence on lead 81 is therefore (l, +2, 1 Leads 65 and 81 are connected together, and the two output sequences (+1, +2, +1 and (l +2, l) combine to produce a single output pulse (+4), which is applied across a suitable load 94 such as a load resistor.
  • a suitable load 94 such as a load resistor.
  • the transducers shown in FIG. 3 There are several advantages obtained by the transducers shown in FIG. 3. There are only two leads connected to the source or the load, therefore, no center ground is required. One of the leads can be grounded; and, hence, the source or the load need not be balanced about the ground potential. There are the same number of electrodes connected to each lead of the transducer; and, therefore, the transducer is well balanced. Also, the surface wave pulse sequences are returnto-zero binary pulses in accordance with proper coding technique.
  • the complementary transducers can also be connected as shown in FIG. 5 wherein the leads to the transducer are much simplified. The result of the operation of FIG. 5 is the same as that of FIG. 3 by the nature of the complementary series, that is, a pair of complementary series is still complementary when one sequence of the pair changes sign.
  • FIG. 6 Another embodiment of the invention is shown in FIG. 6.
  • the output transducer consists of a cascaded number of the previously described transducers and is designed to perform a binary sequence pattern recognition.
  • the particular embodiment can be used to recognize a three-digit Barker code sequence.
  • the output electrical signal is maximum.
  • the function of the angled electrodes is the same as in FIGS. 3 and 5.
  • the acoustic pulse sequences produced by the input transducer 100 are depicted in FIG. 6 and the resultant electrical output signal from output transducer 102 is also shown.
  • the sections of the transducers can be increased or changed in polarity to recognize any length of binary sequence for any type of code used in information processing.
  • auxiliary electrode 46 or 48 may be eliminated.
  • the undesired pulse will reach the detector transducer, depending on the distance between the generator transducer and the detector transducer.
  • the undesired pulse will have a wavefront direction different from the otherpulses, that is, it will not be parallel to the wavefronts of the pulses desired to be detected.
  • any signal produced by the undesired pulse at the detector transducer will be negligibly small.
  • An interdigital transducer device for processing surface wave pulse trains comprising a first interdigital transducer structure including first and second parallel leads,
  • a first plurality of linear main electrodes located between said first and second parallel leads and connected perpendicularly to said first lead;
  • a second plurality of linear main electrodes located between said first and second parallel leads and connected perpendicularly to said second lead;
  • a first plurality of linear auxiliary electrodes located in parallel between said first and second parallel leads and disposed at an oblique angle to said first and second parallel leads
  • a second interdigital transducer structure including third and fourth parallel leads located adjacent and parallel to said first and second parallel leads,
  • a third plurality of linear main electrodes located between said third and fourth parallel leads and connected perpendicularly to said fourth lead;
  • An interdigital transducer device according to claim 1 further including means for connecting said first and third leads together,
  • a substrate for supporting said first and second interdigital transducer structures said substrate being composed of material capable of propagating acoustic surface waves;
  • first and second interdigital transducer structures are responsive to an input electrical said for propagating a first train of acoustic surface wave pulses on said substrate from said first transducer structure and a second train of acoustic surface wave pulses on said substrate from said second transducer structure;
  • said first and second pulse trains propagating in parallel in a given direction.
  • An interdigital transducer device wherein said main electrodes propagate pulses in a first direction and said auxiliary electrodes propagate pulses in a second direction different from said first direction.
  • An interdigital transducer device further including a third interdigital transducer structure identical to said first transducer structure and a fourth transducer structure identical to said second transducer structure, said third and fourth transducer structure being located adjacent to each other on said substrate in the path of said first and second pulse trains respectively,
  • said third and fourth transducer structures being responsive to said acoustic pulses propagated by saild main electrodes of said first and second transducer structures respectively for producing a related electrical signal.
  • An interdigital transducer device for processing surface wave pulse trains comprising a first interdigital transducer structure including first and second parallel leads,
  • a first plurality of linear main electrodes located between said first and second parallel leads and connected perpendicularly to said first lead;
  • a second plurality of linear main electrodes located between said first and second parallel leads and connected perpendicularly to said second lead;
  • a first plurality of linear auxiliary electrodes located in parallel between said first and second parallel leads and disposed at an oblique angle to said first and second parallel leads
  • a second interdigital transducer structure including a third lead parallel and adjacent to said second lead
  • a third plurality of linear main electrodes located between said second and third parallel leads and connected perpendicularly to said second lead;
  • a fourth plurality of linear main electrodes located between said second and third parallel leads and connected perpendicularly to said third lead;
  • An interdigital transducer device further including a substrate for supporting said first and second interdigital transducer structures, said substrate being composed of material capable of propagating acoustic surface waves,
  • first and second interdigital transducer structures are responsive to an input electrical signal for propagating a first train of acoustic surface waves on said substrate from said first transducer structure and a second train of acoustic surface waves from said second transducer structure,
  • said first and second pulse trains propagating in parallel in a given direction.
  • An interdigital transducer device wherein said main electrodes propagate pulses in a first direction and said auxiliary electrodes propagate pulses in a second direction different from said first direction.
  • An interdigital transducer device further including a third interdigital transducer structure identical to said first transducer structure and a fourth transducer structure identical to said second transducer structure, said third and fourth transducer structure being located adjacent to each other on said substrate in the path of said first and second pulse trains respectively,
  • said third and fourth transducer structures being responsive to said acoustic pulses propagated by said main electrodes of said first and second transducer structures respectively for producing a related electrical signal.

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
  • Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)
  • Dc Digital Transmission (AREA)
  • Pulse Circuits (AREA)
US76942A 1970-09-30 1970-09-30 Surface wave transducer for digital signals Expired - Lifetime US3680007A (en)

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US7694270A 1970-09-30 1970-09-30

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US (1) US3680007A (de)
JP (1) JPS5329058B1 (de)
DE (1) DE2139200C3 (de)
FR (1) FR2105867A5 (de)
GB (1) GB1345731A (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3770949A (en) * 1972-04-21 1973-11-06 Us Navy Acoustic surface wave correlators and convolvers
US3831044A (en) * 1973-11-07 1974-08-20 Us Navy Coded grating transducer
US3961290A (en) * 1975-02-07 1976-06-01 Texas Instruments Incorporated Programmable phase coded surface wave device
US3978437A (en) * 1974-07-02 1976-08-31 British Secretary of State for Defence Surface acoustic wave devices
US3980962A (en) * 1974-02-15 1976-09-14 The General Electric Company Limited Demodulators
US4263569A (en) * 1978-09-13 1981-04-21 Siemens Aktiengesellschaft Surface acoustic wave arrangement with improved suppression of spurious signals
US20060146314A1 (en) * 2002-04-11 2006-07-06 Fujitsu Limited Elastic-wave monitoring device and surface-acoustic-wave device
RU2754124C1 (ru) * 2020-10-29 2021-08-27 Федеральное государственное бюджетное учреждение науки Институт радиотехники и электроники им. В.А. Котельникова Российской академии наук Способ формирования последовательности видеоимпульсов с использованием акустической линии задержки

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1202384A (en) * 1983-12-22 1986-03-25 Grantley O. Este Magnetic feedthrough cancelling surface acoustic wave device
DE4010310A1 (de) * 1990-03-30 1991-10-02 Siemens Ag Oberflaechenwellenwandler, insbesondere in splitfinger-ausfuehrung, mit unterdrueckung von reflexionen endstaendiger wandlerfinger

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3376572A (en) * 1966-09-15 1968-04-02 Rca Corp Electroacoustic wave shaping device
US3548306A (en) * 1968-08-29 1970-12-15 Us Navy Surface wave spectrum analyzer and interferometer
US3551837A (en) * 1969-08-13 1970-12-29 Us Navy Surface wave transducers with side lobe suppression
US3559115A (en) * 1968-02-28 1971-01-26 Zenith Radio Corp Surface-wave filter reflection cancellation
US3568102A (en) * 1967-07-06 1971-03-02 Litton Precision Prod Inc Split surface wave acoustic delay line
US3573673A (en) * 1969-01-08 1971-04-06 Zenith Radio Corp Acoustic surface wave filters

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3376572A (en) * 1966-09-15 1968-04-02 Rca Corp Electroacoustic wave shaping device
US3568102A (en) * 1967-07-06 1971-03-02 Litton Precision Prod Inc Split surface wave acoustic delay line
US3559115A (en) * 1968-02-28 1971-01-26 Zenith Radio Corp Surface-wave filter reflection cancellation
US3548306A (en) * 1968-08-29 1970-12-15 Us Navy Surface wave spectrum analyzer and interferometer
US3573673A (en) * 1969-01-08 1971-04-06 Zenith Radio Corp Acoustic surface wave filters
US3551837A (en) * 1969-08-13 1970-12-29 Us Navy Surface wave transducers with side lobe suppression

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3770949A (en) * 1972-04-21 1973-11-06 Us Navy Acoustic surface wave correlators and convolvers
US3831044A (en) * 1973-11-07 1974-08-20 Us Navy Coded grating transducer
US3980962A (en) * 1974-02-15 1976-09-14 The General Electric Company Limited Demodulators
US3978437A (en) * 1974-07-02 1976-08-31 British Secretary of State for Defence Surface acoustic wave devices
US3961290A (en) * 1975-02-07 1976-06-01 Texas Instruments Incorporated Programmable phase coded surface wave device
US4263569A (en) * 1978-09-13 1981-04-21 Siemens Aktiengesellschaft Surface acoustic wave arrangement with improved suppression of spurious signals
US20060146314A1 (en) * 2002-04-11 2006-07-06 Fujitsu Limited Elastic-wave monitoring device and surface-acoustic-wave device
US7362033B2 (en) * 2002-04-11 2008-04-22 Fujitsu Limited Surface-acoustic-wave device
US20080189665A1 (en) * 2002-04-11 2008-08-07 Fujitsu Limited Surface-acoustic-wave device
RU2754124C1 (ru) * 2020-10-29 2021-08-27 Федеральное государственное бюджетное учреждение науки Институт радиотехники и электроники им. В.А. Котельникова Российской академии наук Способ формирования последовательности видеоимпульсов с использованием акустической линии задержки

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Publication number Publication date
GB1345731A (en) 1974-02-06
JPS5329058B1 (de) 1978-08-18
DE2139200B2 (de) 1979-11-29
FR2105867A5 (de) 1972-04-28
DE2139200C3 (de) 1980-10-02
DE2139200A1 (de) 1972-04-06

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