WO2018060705A1 - Arrangement d'hétérodynage - Google Patents

Arrangement d'hétérodynage Download PDF

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Publication number
WO2018060705A1
WO2018060705A1 PCT/GB2017/052899 GB2017052899W WO2018060705A1 WO 2018060705 A1 WO2018060705 A1 WO 2018060705A1 GB 2017052899 W GB2017052899 W GB 2017052899W WO 2018060705 A1 WO2018060705 A1 WO 2018060705A1
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WO
WIPO (PCT)
Prior art keywords
arrangement according
arrangement
electrical signals
input
heterodyne
Prior art date
Application number
PCT/GB2017/052899
Other languages
English (en)
Inventor
David HORSELL
Mark Heath
Original Assignee
University Of Exeter
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University Of Exeter filed Critical University Of Exeter
Publication of WO2018060705A1 publication Critical patent/WO2018060705A1/fr

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C1/00—Amplitude modulation
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R23/00—Transducers other than those covered by groups H04R9/00 - H04R21/00
    • H04R23/002—Transducers other than those covered by groups H04R9/00 - H04R21/00 using electrothermic-effect transducer

Definitions

  • This invention relates to a heterodyning arrangement whereby a heterodyne (frequency mixed) output signal can be obtained from a plurality of input signals.
  • a heterodyne (frequency mixed) output signal can be obtained from a plurality of input signals.
  • it relates to an arrangement in which such a heterodyne signal can be formed through the use of the thermoacoustic effect.
  • Heterodyning is a signal processing technique in which two or more input signals are mixed or combined in such a manner as to produce an output signal including additional frequencies over and above those present in the input signals.
  • the output signal will include signal components at the frequencies f A +f B and ⁇ ⁇ - ⁇ -
  • one or other of these heterodyne components is often filtered out.
  • a number of devices are known for producing heterodyne outputs from input signals, these devices typically comprising diodes or other non-linear components.
  • Heterodyning is used extensively in telecommunications and signal processing applications. In addition, it is used in acoustic metrology, gas sensing and in chemical spectroscopy.
  • the present invention relates to a relatively simple arrangement whereby such heterodyning may be accomplished.
  • a heterodyning arrangement comprising a conductive material element, at least one terminal whereby first and second electrical signals can be applied to the element, the application of the electrical signals to the element result in Joule heating thereof which, in turn, results in the generation of a pressure wave via the thermoacoustic effect, and a sensor operable to produce an electrical output signal related to the pressure wave, the electrical output signal comprising a heterodyne of the first and second electrical signals.
  • the conductive material element conveniently comprises a graphene material element.
  • the output pressure wave contains a heterodyne mix of the input electrical signals, and hence that the arrangement can be used in the generation of heterodyne mixes of, for example, audio signals represented by the electrical signals.
  • the sensor may take the form of a microphone, for example a condensing microphone. It will be appreciated, however, that other forms of sensor may be used.
  • the graphene material element is preferably mounted upon a support substrate.
  • a support substrate By way of example, it may be mounted upon a substrate of Si0 2 or quartz.
  • the first input terminal may be of comb-like form.
  • the conductive material element is further provided with a ground terminal.
  • the ground terminal like the first input terminal, is conveniently of comb-like form. Where both terminals are of comb like form, the teeth of the combs are conveniently arranged in an interlaced or interdigitated fashion.
  • the invention also relates to a method of producing a heterodyne output from a first input electrical signal and a second input electrical signal comprising the steps of applying the first and second electrical signals to a conductive material element, the application of the electrical signals to the element resulting in Joule heating thereof and thus in the generation of a pressure wave via the thermoacoustic effect, the pressure wave including heterodyne components of the first and second input electrical signals.
  • Figures 1 and 1 a are diagrammatic representations illustrating a heterodyning arrangement in accordance with an embodiment of the invention.
  • FIG. 2 is a graph illustrating an output achieved using the arrangement of Figures 1 and 1 a.
  • the arrangement comprises a graphene material element 10 upon which are provided input and ground terminals 12, 14.
  • Each of the terminals 12, 14 is of comb-like form, each including a series of generally parallel teeth 12a, 14a, the teeth 12a of the input terminal 12 being interconnected by a common region 12b, and the teeth 14a being interconnected by a common region 14b.
  • the teeth 12a are interleaved or interdigitated with the teeth 14a.
  • Such an arrangement is advantageous in that the resistance of the arrangement may be relatively low.
  • the common region 12b of the input terminal 12 is connected, via a suitable electrical lead (not shown) to the outputs of a pair of signal generators arranged to output respective electrical signals.
  • the two electrical signals are intended to be received simultaneously, in use.
  • the common region 14b of the ground terminal 14 is connected to ground.
  • the application of electrical currents to conductive materials results in Joule heating thereof.
  • steps are taken to minimise the level of heating that occurs, and to dissipate heat generated in this manner.
  • the Joule heating effect that arises from the application of an electrical current to the graphene element 10 through the application of the electrical signal to the input terminal 12 (and the connection of the ground terminal 14 to the element 10) is used in the formation of a heterodyne output.
  • Graphene having a very high thermal conductivity and a low heat capacity, is particularly suitable for use in applications in which thermoacoustic effects are to be utilized.
  • the Joule heating of the element 10 results in the formation of pressure waves in the air surrounding the element 10, the pressure waves containing heterodyne components of the two input audio signals.
  • the sound pressure in air resulting from Joule heating can be represented by the equation where P is the power, f is the frequency of the input signal, r is the distance from the element 10, and ⁇ is related to the thermal effusivity of the air relative to the total effusivity of the system. It will be appreciated, therefore, that the pressure is related to the signal power and to the frequency of the input signal.
  • an element 10 is driven using a signal made up of two (or more) component signals that may be of different frequencies, f A and f B , the power dissipated through the Joule heating effect can be approximated as
  • a sensor 16 sensitive to the air pressure in the vicinity of the element 10 is provided.
  • the sensor 16 conveniently takes the form of a microphone.
  • Figure 2 illustrates, diagrammatically, the output signal 18 from the sensor 16 where the first and second input signals are at frequencies f A and f B . It is clear from Figure 2 that peaks occur at the frequencies 2f A and 2f B , these peaks being indicative of the second harmonics, as mentioned above. Furthermore, a peak arises at the frequency f A+ B, indicative of one of the heterodyne components. Although not shown, a peak representative of the other of the heterodyne frequencies would also exist.
  • the arrangement shown in Figure 1 serves as a heterodyning arrangement, producing an output in the form of a heterodyne mix of the input signals. Whilst described as producing a heterodyne mix of two input signals, the arrangement may be used, if desired, in producing a mix of a greater number of inputs. Furthermore, it is clear that the methodology described hereinbefore may be used in the production of a heterodyne mix. Whilst the graphene element 10, terminals 12, 14 and sensor 16 may take a wide range of forms, in one example arrangement, the graphene element 10 is of monolayer form of generally square shape, having sides of length 6mm. The graphene element 10 is located upon a Si0 2 or quartz substrate.
  • the sensor 16 takes the form of a condenser microphone.
  • the graphene element 10 and terminals 12, 14 may be of back gated or top gated form.
  • the fabrication of one example of a back gated arrangement involves transferring a CVD grown monolayer of graphene to a degenerately doped silicon substrate coated with 300nm silicon dioxide. 50nm thick gold terminals 12, 14 are formed in the desired shape by thermal evaporation directly onto the graphene. A thin layer of Cr may be used to anchor extensions of the terminals 12, 14 to the substrate surface.
  • the spacings between the interleaved or interdigitated parts of the terminals 12, 14 are preferably in the region of 100-200 ⁇ .
  • the heterodyning arrangement of the invention may be employed in a wide range of applications in which it is desired to produce a heterodyne mix of two or more input signals.
  • it may be employed in a number of telecommunications and signal processing applications.
  • Other applications in which the arrangement may be used include as a switch suitable for use in supercomputing or the like technologies, or in acoustic metrology, gas sensing and in chemical spectroscopy technologies.
  • the arrangement of the invention is advantageous compared to known heterodyning arrangements in that the arrangement is linear.
  • the arrangement further allows the user a great deal of control over the output mixed signal produced in that the amplitude of the output mixed signal scales linearly with the amplitudes of the input signals, and these can readily be controlled independently of one another.
  • the mixed output will have the same frequency as the other of the input signals, plus the heterodyne outputs, but has an amplitude that is linearly related to the amplitude of the input DC signal.
  • the element takes the form of a monolayer graphene element. It will be appreciated, however, that whilst graphene is a material particularly suitable for use in the invention, a number of other conductive materials may be used without departing from the scope of the invention.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Carbon And Carbon Compounds (AREA)

Abstract

L'invention concerne un arrangement d'hétérodynage qui comprend un élément en matériau conducteur, par exemple sous la forme d'un élément en graphène, au moins une première borne d'entrée (12) par laquelle des signaux électriques associés à un premier signal électrique d'entrée et à un deuxième signal électrique d'entrée peuvent être appliqués à l'élément (10). L'application des signaux électriques à l'élément (10) donne lieu à un chauffage par effet Joule de celui-ci qui, à son tour, résulte en la sortie d'une onde de pression. L'objet de l'invention comprend également un capteur (16) qui peut être utilisé pour produire une (10) sortie électrique associée à l'onde de pression. L'invention concerne également un procédé de production d'une sortie hétérodyne en utilisant un tel arrangement.
PCT/GB2017/052899 2016-09-29 2017-09-28 Arrangement d'hétérodynage WO2018060705A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB1616512.8 2016-09-29
GBGB1616512.8A GB201616512D0 (en) 2016-09-29 2016-09-29 Heterodyning arrangement

Publications (1)

Publication Number Publication Date
WO2018060705A1 true WO2018060705A1 (fr) 2018-04-05

Family

ID=57571219

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2017/052899 WO2018060705A1 (fr) 2016-09-29 2017-09-28 Arrangement d'hétérodynage

Country Status (2)

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GB (1) GB201616512D0 (fr)
WO (1) WO2018060705A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110868677A (zh) * 2019-11-07 2020-03-06 天津大学 一种新型石墨烯扬声器
WO2020178558A1 (fr) 2019-03-06 2020-09-10 Cambridge Enterprise Limited Émetteurs et récepteurs

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2061098A1 (fr) * 2006-09-05 2009-05-20 Pioneer Corporation Dispositif de generation de son thermique
JP2009239518A (ja) * 2008-03-26 2009-10-15 Quantum 14:Kk デジタル・スピーカー
US20100220876A1 (en) * 2005-06-24 2010-09-02 Koninklijke Philips Electronics, N.V. Thermo-acoustic transducers
US20120250908A1 (en) * 2011-03-29 2012-10-04 Hon Hai Precision Industry Co., Ltd. Thermoacoustic device
US20140140549A1 (en) * 2012-11-20 2014-05-22 Hon Hai Precision Industry Co., Ltd. Thermoacoustic chip
US20150104046A1 (en) * 2013-10-11 2015-04-16 Turtle Beach Corporation Parametric transducer with graphene conductive surface

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100220876A1 (en) * 2005-06-24 2010-09-02 Koninklijke Philips Electronics, N.V. Thermo-acoustic transducers
EP2061098A1 (fr) * 2006-09-05 2009-05-20 Pioneer Corporation Dispositif de generation de son thermique
JP2009239518A (ja) * 2008-03-26 2009-10-15 Quantum 14:Kk デジタル・スピーカー
US20120250908A1 (en) * 2011-03-29 2012-10-04 Hon Hai Precision Industry Co., Ltd. Thermoacoustic device
US20140140549A1 (en) * 2012-11-20 2014-05-22 Hon Hai Precision Industry Co., Ltd. Thermoacoustic chip
US20150104046A1 (en) * 2013-10-11 2015-04-16 Turtle Beach Corporation Parametric transducer with graphene conductive surface

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
HALL ASHA ET AL: "Signal conditioning of carbon nanotube thin film loudspeakers", 14TH IEEE INTERNATIONAL CONFERENCE ON NANOTECHNOLOGY, IEEE, 18 August 2014 (2014-08-18), pages 668 - 671, XP032690953, DOI: 10.1109/NANO.2014.6968142 *
M. S. HEATH ET AL: "Multi-frequency sound production and mixing in graphene", SCIENTIFIC REPORTS, vol. 7, no. 1, 2 May 2017 (2017-05-02), XP055431036, DOI: 10.1038/s41598-017-01467-z *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020178558A1 (fr) 2019-03-06 2020-09-10 Cambridge Enterprise Limited Émetteurs et récepteurs
US11695479B2 (en) 2019-03-06 2023-07-04 Consorzio Nazionale Interuniversitario Per Le Telecomunicazioni Transmitters and receivers
CN110868677A (zh) * 2019-11-07 2020-03-06 天津大学 一种新型石墨烯扬声器

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