<PAGE>   1
                                                                     EXHIBIT 4.7

                                 DEED OF TRUST



STATE OF TEXAS                        )
                                      )       KNOW ALL MEN BY THESE PRESENTS:
COUNTY OF NUECES                      )



That TEXAS AIRSONICS, INC., whose address is 5555 Bear Lane, Corpus Christi,
Texas 78405, hereinafter called "Mortgagor" (whether one or more) for the
purpose of securing the indebtedness hereinafter described, and in
consideration of the sum of TEN DOLLARS ($10.00) to Mortgagor in hand paid by
the Trustee hereinafter named, the receipt of which is hereby acknowledged, and
for the further consideration of the uses, purposes and trusts hereinafter set
forth, has granted, sold and conveyed, and by these presents does grant, sell
and convey unto The International Bank, Trustee, whose address is P. O. Drawer
4956, Corpus Christi, Texas 78469 and his or its substitutes or successors, all
of the following described property, to-wit:


         (a)  That land located in Nueces County, Texas more particularly
              described as follows:

              Lot One (1), Block Two (2), INDUSTRIAL TECHNOLOGY PARK UNIT 1, a
              subdivision of the City of Corpus Christi, Nueces County, Texas
              as shown by the map or plat thereof recorded in Volume 46,
              Pages 105-107, Map Records, Nueces County, Texas.


         (b)  All improvements now or hereafter situated on said land, and all
              the rights, hereditaments and appurtenances in anywise
              appertaining or belonging thereto.


         (c)  All proceeds now or hereafter arising from the foregoing listed
              properties and types of properties.   

              All of the above types and items of properties are herein
              referred to as the "property". 

       This conveyance is subject to all lawful restrictive covenants and
easements, if any, of record in the office of the County Clerk of the County in
which said land is located and presently in force and affecting said land.
There is also excepted herefrom all oil, gas and other minerals, if any,
heretofore conveyed to others or reserved by Mortgagor's predecessors in title
as shown by the records of said Clerk.


       TO HAVE AND TO HOLD the above described property, together with the
rights, privileges and appurtenances thereto belonging unto the said Trustee,
and to the said Trustee's substitutes or successors forever.  And Mortgagor
does hereby bind itself and its successors to warrant and forever defend the
property unto the said Trustee, and the Trustee's substitutes or successors and
assigns forever, against the claim, or claims, of all persons claiming or to
claim the same or any part thereof.


This conveyance, however, is made in TRUST to secure payment of the following:

         (a)  That certain promissory note of even date herewith executed by
              Texas AirSonics, Inc. and American Dental Technologies, Inc.
              payable to the order of THE INTERNATIONAL BANK (herein called
              "Beneficiary") whose address is P. O. Drawer 4956, Corpus
              Christi, Texas 78469, described as follows, to-wit:


                   In the original principal sum of TWO MILLION FIVE HUNDRED
                   THOUSAND DOLLARS ($2,500,000.00) maturing October 15, 1997.


         (b)  Any sums which may hereafter be advanced by Beneficiary under the
              terms hereof together with interest thereon and attorney's fees as
              hereinafter provided;


         (c)  Any additional loans made by Beneficiary to Mortgagor,
              however evidenced; and in this connection it is contemplated that
              Beneficiary may lend additional sums to Mortgagor from time to
              time, but shall not be obligated to do so, and Mortgagor
              agrees that if Mortgagor should become indebted to Beneficiary in
              any such additional sum or sums the same shall be secured by this
              instrument as well as any other security which Beneficiary may
              now or hereafter hold for the payment thereof; and,


         (d)  Any and all other indebtedness, obligations or other
              liabilities of Mortgagor to Beneficiary now or hereafter owing,   
              whether direct or indirect, primary or secondary, fixed or
              contingent, matured or unmatured, joint or several, regardless of
              how evidenced or arising.


         (e)  Any and all renewals and extensions of the foregoing, regardless 
              of the number of or length of time of such renewals and
              extensions, and regardless of whether or not Mortgagor joins in
              or executes an agreement relating to such renewals and extensions.

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Provided, notwithstanding the foregoing, the liens and security interests
herein provided shall not secure any indebtedness arising under or by reason of
loans pursuant to Subtitles Two or Three, such being Chapters 2 through 15, of
the Texas Credit Code, Article 5069 V.A.T.S.

       Should Mortgagor do and perform all of the covenants and agreements
herein contained, and make prompt payment of said indebtedness as the same
shall become due and payable, then this conveyance shall become null and void
and of no further force and effect, and shall be released at the expense of
Mortgagor, by the holder thereof, herein called "Beneficiary" (whether one or
more).

       Mortgagor covenants and agrees as follows:

       That Mortgagor is lawfully seized of said property, and has the right to
convey the same; that said property is free from all liens and encumbrances
except as may herein be specifically set forth.

       To protect the title and possession of said property and to pay when due
all taxes and assessments now existing or hereafter levied or assessed upon
said property, or the interest therein created by this Deed of Trust, and to
preserve and maintain the lien hereby created prior to all other liens except
as may herein be specifically provided, and to not place or allow the creation
or placement of any other liens on said property without the prior written
approval of Beneficiary.

       To keep the improvements on said land, and any goods covered hereby,
in good repair and condition, and not to permit or commit any waste thereof;
to keep all buildings occupied so as not to impair the insurance carried
thereon.

       To insure and keep insured all improvements now or hereafter created
upon said land, and the goods covered hereby, against loss or damage by fire
and windstorm, and any other hazard or hazards (including but not limited to
flood insurance if in a special flood hazard area designated by HUD) as may be
reasonably required from time to time by Beneficiary during the term of the
indebtedness hereby secured, to the extent of the amount of the indebtedness
hereby secured, or to the extent necessary to prevent Mortgagor from being a
co-insurer under the insurance policies, whichever is the greater, in such form
and with such insurance company or companies as may be approved by Beneficiary,
and to deliver to Beneficiary the policies of such insurance having attached to
said policies such mortgage indemnity clause as Beneficiary shall direct; to
deliver renewals of such policies to Beneficiary at least ten (10) days before
any such insurance policies shall expire; any proceeds which Beneficiary may
receive under any such policy, or policies, may be applied by Beneficiary at
his own option, to reduce the indebtedness hereby secured, whether then matured
or to mature in the future, and in such manner as Beneficiary may elect, or
Beneficiary may permit Mortgagor to use said proceeds to repair or replace all
improvements damaged or destroyed and covered by said policy.

       To comply with all terms and conditions of any loan agreement made in
connection with the indebtedness secured hereby.

       If requested by Beneficiary to provide within 30 days of a request being
made, an appraisal by an MAI appraiser or other appraiser approved by
Beneficiary, and Mortgagor agrees that if Mortgagor does not timely comply with
a request made for an appraisal that Beneficiary may obtain such appraisal at
Mortgagor's expense.

       To provide Beneficiary on at least an annual basis, with each
Mortgagor's and each Maker's financial statements including a current balance
sheet, current income statement and current statement of sources and uses of
cash.

       Within 15 days of demand made by Beneficiary, to make an initial deposit
in a reasonable amount determined by Beneficiary and then monthly payments to a
fund for taxes and insurance premiums on the property.  Monthly payments will
be made on the payment date specified in the note, and each payment will be
1/12 of the amount that Beneficiary estimates will be required annually for
payment of taxes and insurance premiums.  The fund will accrue no interest, and
Beneficiary will hold it without bond in escrow and use it to pay the taxes and
insurance premiums.  If Mortgagor has complied with the requirements of this
paragraph, Beneficiary must pay the taxes before delinquency.  Mortgagor agrees
to make additional deposits on demand if the fund is ever insufficient for its
purpose.  If an excess accumulates in the fund, Beneficiary may either credit
it to future monthly deposits until the excess is exhausted or refund it to
Mortgagor.  Before Mortgagor makes the final payment on the note, Beneficiary
will credit to that payment the whole amount then in the fund or, at
Beneficiary's option, refund it after the note is paid.  If this Deed of Trust
is foreclosed, any balance in the fund over that needed to pay taxes, including
taxes accruing but not yet payable, and to pay insurance premiums will be first
applied to the balance, if any, of indebtedness secured hereby and the
remainder, if any, refunded to Mortgagor.  Deposits to the fund described in
this paragraph are in addition to the monthly payments provided for in the
note.

       To the extent not prohibited by law, Mortgagor will pay, or reimburse
Beneficiary for, all costs and expenses, of every character, incurred or
expended from time to time (including, but not limited to, the fees and
expenses of counsel for Beneficiary) in connection with the negotiation,
preparation, execution, filing, recording, refiling and re-recording of this
Deed of Trust and all related financing statements and the making, servicing
and collection of the debt secured hereby; any and all stamp, mortgage and
recording taxes; the costs of any title insurance or lien insurance purchased
by Beneficiary in connection herewith; all costs of negotiation, preparation,
execution and delivery of any and all amendments, modifications, supplements,
consents, waivers or other documents or writings relating to the transactions
contemplated by this Deed of Trust; and all costs (including attorneys' fees)
of reviewing title opinions and security opinions relating to the debt secured
hereby.
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       With respect to any substances defined as or included in the definition
of "hazardous substances," "hazardous wastes," "hazardous materials" or "toxic
substances" under any applicable federal, state or local laws, ordinances or
regulations (including, without limitation, friable asbestos and asbestos
deemed hazardous by federal or state regulations) (such substances collectively
referred to hereinafter as "Hazardous Materials" and such laws, ordinances and
regulations together with all rules, orders and permits pursuant thereto
collectively referred to hereinafter as "Hazardous Materials Laws"), Mortgagor:

    (a)  represents that (except as to Hazardous Materials violations that have
         been remedied as required by governmental authorities having
         jurisdiction of the matter) neither Mortgagor nor any affiliate,
         employee, or agent of Mortgagor nor, to the best of Mortgagor's
         knowledge, any of Mortgagor's predecessors in title (i) has ever
         stored, buried, installed, transported, treated or disposed of any
         Hazardous Materials at, to or from the property in violation of any
         applicable Hazardous Materials Laws, (ii) has ever caused or was
         legally responsible for the release, discharge, emission, leak, spill
         or dumping of any Hazardous Materials at or from the property except
         for those releases allowed under applicable Hazardous Materials Laws,
         or (iii) has ever received notification from any federal, state or
         other governmental authority of the presence or potential or actual
         release of any Hazardous Materials at or from the property;

    (b)  covenants to (i) comply with all applicable Hazardous
         Materials Laws with respect to the manufacture, storage, transmission,
         presence, discharge and removal of Hazardous Materials at or from the
         property, (ii) pay promptly when due the costs of any required removal
         of any Hazardous Materials from the property and to keep the property
         free of any lien imposed pursuant to any Hazardous Materials Laws,
         (iii) not locate nor allow location of any underground storage tanks
         on the property, and (iv) notify Beneficiary promptly in writing of
         the commencement of any legal or regulatory proceedings relating to
         Hazardous Materials affecting the property; and

    (c)  agrees to indemnify and to hold harmless Beneficiary,
         its officers, employees, agents, successors and assigns (the
         "Indemnitees") from and against, and to reimburse the Indemnitees with
         respect to, any and all claims, demands, causes of action, loss,
         damage, liabilities, costs, and expenses (including attorneys' fees
         and court costs) of any and every kind or character, known or unknown,
         fixed or contingent, asserted against or incurred by the Indemnitees
         at any time or from time to time, whether as beneficiary under the
         Deed of Trust, as mortgagee in possession, or as successor-in-interest
         to Mortgagor by foreclosure deed or deed in lieu of foreclosure, by
         reason of or arising out of any violation of any Hazardous Materials
         Laws (including, without limitation, all claims, demands, loss,
         damage, liabilities, costs and expenses in connection with the
         presence on the property or release from or to the property of
         Hazardous Materials disposed of or otherwise released), regardless of
         whether the act, omission, event, or circumstance constituted a
         violation of applicable law at the time of existence or occurrence. 
         Mortgagor's obligations hereunder shall arise upon the discovery of
         the presence of any Hazardous Materials, whether or not any federal
         agency or any state or local environmental agency has taken or
         threatened any action in connection with the presence of any Hazardous
         Materials.  The foregoing indemnity shall survive the repayment of the
         indebtedness secured hereby and the release of the lien of the Deed of
         Trust and shall survive the transfer of any or all right, title and
         interest in and to the property by Mortgagor to any other party.

In the event Mortgagor fails, after reasonable notice, to pay any amounts
described in clause (b)(ii) immediately above, Beneficiary may, but shall not
be obligated to, cause the Hazardous Materials to be removed from the property
and the cost of such removal shall be added to the indebtedness secured hereby
(regardless of whether such addition increases the outstanding balance of the
indebtedness secured hereby to an amount in excess of the face amount of any
notes described herein).  Beneficiary shall have the right at reasonable times
and reasonable intervals, following reasonable advance notice to Mortgagor, to
conduct an environmental audit of the property and Mortgagor shall cooperate in
the conduct of such environmental audit.  Mortgagor shall pay the cost of
environmental audits of the property conducted for the benefit or at the
request of Beneficiary.

       That in the event Mortgagor shall fall to keep the improvements on the
land hereby conveyed or the goods covered hereby in good repair and condition,
or to pay promptly when due all taxes and assessments, as aforesaid, or to
preserve the lien status as herein warranted on said property, or to keep the
buildings, improvements and goods insured, as aforesaid, or to deliver the
policy, or policies, of insurance or the renewal thereof to Beneficiary, as
aforesaid, or to promptly, fully and timely observe or perform any covenant or
obligation of Mortgagor contained herein, then Beneficiary may, at its option,
but without being required to do so, make such repairs, pay such taxes and
assessments, purchase any tax title thereon. remove any other liens, and
prosecute or defend any suits in relation to the preservation of the lien
status herein warranted on said property, or insure and keep insured the
improvements thereon in an amount not to exceed that above stipulated, or
perform such other covenants and obligations.

       Mortgagor will reimburse Beneficiary for all amounts expended by
Beneficiary to satisfy any obligation of Mortgagor under this Deed of Trust or
to protect the Property.  In addition, whether or not a default shall have
occurred, Mortgagor will pay, or reimburse Beneficiary for, all costs and
expenses, of every character incurred or expended from time to time in
connection with the evaluation, monitoring, administration and protection of
the Property, the exercise by Beneficiary of any of its rights and remedies
hereunder or at law (including, but not limited to all appraisal fees,
consulting fees, brokerage fees and commissions, insurance premiums, Uniform
Commercial Code search fees, fees incident to title searches and reports,
investigation costs, escrow fees, attorneys' fees, legal expenses, fees of
auditors and accountants, court costs, fees of governmental authorities,
auctioneer fees and expenses, and all fees and expenses incurred in connection
with the marshalling, guarding, management,

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<PAGE>   4
operation, removal, maintenance, cleanup, storage, auction and liquidation
of the Property). Any amounts to be paid or reimbursed by Mortgagor to
Beneficiary shall be a demand obligation owing by Mortgagor to Beneficiary and,
to the extent not prohibited by law, shall bear interest from the date of
expenditure by Beneficiary until paid at the same rate provided for past-due
principal and interest in the principal obligation (the "Past Due Rate"). The
principal obligation shall be (1) the note secured hereby; (2) if more than one
note is secured hereby, the note with the largest face amount; and (3) if no
note is secured hereby, the obligation with the largest face amount.

        That in the event of default in the payment of any installment, 
principal or interest, of any note or other indebtedness hereby secured, in
accordance with the terms thereof, or of a breach under the terms of any loan
agreement made in connection with indebtedness secured hereby, or of a breach
of any of the covenants herein contained to be performed by Mortgagor, then and
in any of such events Beneficiary may elect, Mortgagor hereby expressly waiving
presentment and demand for payment, to declare the entire principal
indebtedness hereby secured with all interest accrued thereon and all other
sums hereby secured immediately due and payable, and in the event of default in
the payment of said indebtedness when due or declared due, it shall thereupon,
or at any time thereafter, be the duty of the Trustee, or the Trustee's
successor or substitute as hereinafter provided, at the request of Beneficiary
(which request is hereby conclusively presumed), to enforce this trust; and
after advertising the time, place and terms of the sale of the above-described
and conveyed property then subject to the lien hereof which is to be sold as
directed by the Beneficiary, and mailing and filing notices as required by
Section 51.002, Texas Property Code, as then amended (successor to Article 
3810, Texas Revised Civil Statutes), and otherwise complying with that statute,
the Trustee may sell the above-described property then subject to the lien
hereof, or such portions thereof as directed by Beneficiary, at public auction
in accordance with such notices on the first Tuesday in any month between the
hours of ten o'clock A.M. and four o'clock P.M., to the highest bidder for
cash, selling all of the property as an entirety or in such parcels as the
Trustee acting may elect, and make due conveyance to the Purchaser or
Purchasers, with general warranty binding Mortgagor, and Mortgagor's
successors, heirs and assigns; and out of the money arising from such sale, the
Trustee acting shall pay first all the expenses of advertising the sale and
making the conveyance, including a reasonable commission not to exceed five
percent (5%) to the Trustee, which commission shall be due and owing in
addition to the attorney's fees provided for in said note, and then to
Beneficiary the full amount of principal, interest, attorney's fees and other
charges due and unpaid on said note and all other indebtedness secured hereby,
rendering the balance (except for any amounts required by law to be paid
before payment to Mortgagor) of the sales price, if any, to Mortgagor, and
Mortgagor's successors, heirs or assigns; and the recitals in the conveyance to
the Purchaser or Purchasers shall be full and conclusive evidence of the truth
of the matters therein stated, and all prerequisites to said sale shall be
presumed to have been performed, and such sale and conveyance shall be
conclusive against Mortgagor and Mortgagor's successors, heirs and assigns.
Mortgagor will remain liable for any deficiency remaining after a sale or other
disposition hereunder.

        It is agreed that in the event a foreclosure hereunder should be        
commenced by the Trustee, or the Trustee's substitute or successor, Beneficiary
may at any time before the sale of said property direct the said Trustee to
abandon the sale, and may then institute suit for the collection of said note,
and for the foreclosure of this Deed of Trust lien; it is further agreed that
if Beneficiary should institute a suit for the collection thereof, and for a
foreclosure of this Deed of Trust lien, that he may at any time before the
entry of a final judgment in said suit dismiss the same, and require the
Trustee, or the Trustee's substitute or successor, to sell the property in
accordance with the provisions of this Deed of Trust. Sale of a part or parcel
of the property covered hereby shall not exhaust the power of sale, and sales
may be made from time to time until all property covered hereby is sold, or
until all indebtedness secured hereby is paid in full.

        Beneficiary, if it is the highest bidder, shall have the right  to      
purchase at any sale of the property and to have the amount for which such
property is sold credited on the debt then owing.

        Beneficiary in any event is hereby authorized to appoint a substitute   
trustee, or a successor trustee, to act instead of the Trustee named herein
without other formality than the designation in writing of a substitute or
successor trustee; and the authority hereby conferred shall extend to the
appointment of other successor or substitute trustees successively until the
indebtedness hereby secured has been paid in full, or until said property is
sold hereunder, and each substitute and successor trustee shall succeed to all
of the rights and powers of the original trustee named herein.

        In the event any sale is made of the property, or any portion thereof,  
under the terms of this Deed of Trust, Mortgagor, its successors, heirs and
assigns, shall forthwith upon the making of such sale surrender and deliver
possession of the property so sold to the Purchaser at such sale, and in the
event of their failure to do so they shall thereupon from and after the making
of such sale be and continue as tenants at will of such Purchaser, and in the
event of their failure to surrender possession of said property upon demand,
the Purchaser, and the Purchaser's successors, heirs and assigns, shall be
entitled to institute and maintain an action for forcible detainer of said
property in the Justice of the Peace Court in the Justice Precinct in which
such property, or any part thereof, is situated.

        It is agreed that the lien hereby created shall take precedence over
and be a prior lien to any other lien of any character (except for any lien
herein specifically stated to which this Deed of Trust is subject to). whether
vendor's, materialmen's or mechanic's lien hereafter created on the property,
and in the event the proceeds of the indebtedness secured hereby as set forth
herein are used to pay off and satisfy any liens heretofore existing on said
property, then Beneficiary is, and shall be, subrogated to all of the rights,
liens and remedies of the holders of the indebtedness so paid.

        It is further agreed that if Mortgagor, its successors, heirs or        
assigns, while the owner of the hereinabove described property, should commit
an act of bankruptcy, or authorize the filing of a voluntary petition in

                                     -4-
<PAGE>   5

bankruptcy, or should an act of bankruptcy be committed and involuntary
proceedings instituted or threatened, or should the property be taken over by a
receiver for Mortgagor, its heirs, successors or assigns, all indebtedness
secured hereby shall, at the option of Beneficiary, immediately become due and
payable, and the acting Trustee may then proceed to sell the property under the
provisions of this Deed of Trust.

        It is agreed that an extension, or extensions, may be made of the     
time of payment of all, or any part, of the indebtedness secured hereby, and
that any part of the property may be released from this lien without altering
or affecting the priority of the lien created by this Deed of Trust in favor of
any junior encumbrancer, mortgagee or purchaser, or any person acquiring an
interest in the property hereby conveyed, or any part thereof; it being the
intention of the parties hereto to preserve this lien on the land herein
described and all improvements thereon, and that may be hereafter constructed
thereon, first and superior to any liens that may hereafter be placed thereon,
or that may be fixed, given or imposed by law thereon after the execution of
this instrument notwithstanding any such extension of the time of payment, or
the release of a portion of said property from this lien.

        In the event any portion of the indebtedness hereinabove described      
cannot be lawfully secured by the lien herein granted, it is agreed that the
first payments made on said indebtedness shall be applied to the discharge of
that portion of said indebtedness.

        Beneficiary shall be entitled to receive any and all sums which may
become payable to Mortgagor for the condemnation of the hereinabove described
property, or any part thereof, for public or quasi-public use, or by virtue of
private sale in lieu thereof, and any sums which may be awarded or become
payable to Mortgagor for damages caused by public works or construction on or
near the said property. All such sums are hereby assigned to Beneficiary, who
may, after deducting therefrom all expenses actually incurred, including
attorney's fees, release same to Mortgagor or apply the same to the reduction
of the indebtedness hereby secured, whether then matured or to mature in the
future, or on any money obligation hereunder, as and in such manner as
Beneficiary may elect. Beneficiary shall not be, in any event or circumstances,
liable or responsible for failure to collect, or exercise diligence in the
collection of, any such sums.

        Nothing herein or in said note shall ever entitle Beneficiary,  upon
the arising of any contingency whatsoever, to receive or collect interest in
excess of the highest rate allowed by the laws of the State of Texas on the
principal indebtedness hereby secured or on any money obligation hereunder and
in no event shall Mortgagor be obligated to pay interest thereon in excess of
such rate. To the extent permitted by applicable law, determination of the
legal maximum amount of interest shall at all time be made by amortizing,
prorating, allocating and spreading in equal parts during the period of the
full stated term of the Note, all interest at any time contracted for, charged
or received with respect to the Note and the indebtedness, so that the actual
rate of interest with respect to the note and indebtedness is uniform
throughout the stated term of the Note.

        The term "Mortgagor" as used in this instrument will be construed as    
singular or plural to correspond with the number of persons executing this
instrument as Mortgagor. If more than one person executes this instrument as
Mortgagor, his, her, their, or its duties and liabilities under this instrument
will be joint and several, and the grants of liens and security interests
herein made shall cover each such person's joint interest as well as his
several interest in the property mortgaged hereunder. It is intended that the
lien on each particular person's interest executing this instrument as
Mortgagor shall cover the entire indebtedness described herein as being secured
hereby; and it is not intended that the interest of such a particular person in
the property covered hereby shall secure only that particular person's
liability on the indebtedness; nor is it intended that any such particular
person may have that particular person's interest in the property released from
the liens hereof unless and until the entire indebtedness secured hereby has
been satisfied. The terms "Beneficiary" and "Mortgagor" as used in this
instrument include the heirs, executors or administrators, successors,
representatives, receivers, trustees, and assigns of those parties. This
instrument is binding upon the Mortgagor, the Mortgagor's successors, heirs and
assigns (subject to the prohibition of assignment of the property as set forth
herein), and will inure to the benefit of the Trustee and the Trustee's
successors and substitutes and Beneficiary and Beneficiary's successors and
assigns.

        Mortgagor assigns to Beneficiary absolutely, not only as collateral,    
all present and future rent and other income and receipts from the property and
all present and future accounts evidencing or arising from said rents, income
and receipts. Leases are not assigned. Mortgagor warrants the validity and
enforceability of the assignment. Mortgagor may as Beneficiary's licensee
collect rent and other income and receipts as long as Mortgagor is not in
default under the indebtedness secured hereby or this deed of trust. Mortgagor
will apply all rent and other income and receipts to payment of the
indebtedness secured hereby and performance of this deed of trust, but if the
rent and other income and receipts exceed the amount due under the indebtedness
secured hereby and deed of trust, Mortgagor may retain the excess. If Mortgagor
defaults in payment of the indebtedness secured hereby or performance of this
deed of trust, Beneficiary may terminate Mortgagor's license to collect and
then as Mortgagor's agent may rent the property if it is vacant and collect     
all rent and other income and receipts. Beneficiary neither has nor assumes any
obligations as lessor or landlord with respect to any occupant of the property.
Beneficiary shall apply all rent and other income and receipts collected under
this paragraph first to expenses incurred in exercising Beneficiary's rights
and remedies and then to Mortgagor's obligations under the indebtedness secured
hereby and this deed of trust in the order determined by Beneficiary.
Beneficiary is not required to act under this paragraph, and acting under this
paragraph does not waive any of Beneficiary's other rights or remedies. If
Mortgagor becomes a voluntary or involuntary bankrupt, Beneficiary's filing a
proof of claim in bankruptcy will be tantamount to the appointment of a
receiver under Texas law.

        Mortgagor waives the benefit of all laws now in existence or that       
hereafter may be enacted providing for (i) any appraisement before sale of any
portion of the property, commonly known as Appraisement Laws, and (ii) the
benefit of all laws that may be hereinafter enacted in any manner extending the
time for the enforcement of the


                                     -5-
<PAGE>   6

collection of the indebtedness or creating or extending a period of     
redemption from any sale made with respect to the indebtedness, commonly known
as Stay Laws and Redemption Laws, to the extent Mortgagor may lawfully waive
such laws.

        Acceptance by Beneficiary of any payment in an amount less than the     
amount then due shall be deemed as acceptance on account only and the failure
to pay the entire amount then due shall be and continue to be a default by
Mortgagor; and at any time thereafter, and until the entire amount then due has
been paid, Beneficiary shall be entitled to exercise all rights and remedies
conferred it in this instrument or at law upon the occurrence of a default.

        Beneficiary shall have the additional right, upon the commencement of
any action to enforce the lien or security interest herein given, to have
appointed by a court of competent jurisdiction, a receiver to take possession
of the property and to collect all rents, issues, income, and profits arising
from or pertaining to the property. This provision is a right created by this
deed of trust and is cumulative of and is not to affect in any manner the right
of Beneficiary to the appointment of a receiver under any applicable law or
statute.

        In the event Mortgagor conveys or contracts to convey the property      
covered hereby, or any interest in the property covered hereby, including a
leasehold interest, to a party or parties not appearing in this instrument
without the written consent thereto of Beneficiary, then Beneficiary, at its
election exercised any time after such event and without notice to Mortgagor,
may declare the entire indebtedness secured hereby at once due and payable.

        Mortgagor shall not be entitled to release of the liens hereof on any   
portion of the property covered hereby (commonly known as "partial releases")
upon payment of a portion of the indebtedness secured hereby; and the Mortgagor
shall be entitled to release of any property covered hereby only upon
satisfaction in full of the entire indebtedness secured hereby.

        Dated effective the 17th day of October, A.D., 1996.



                                                TEXAS AIRSONICS, INC.


                                                By:   Benjamin J. Gallant
                                                   -------------------------
                                                   Benjamin J. Gallant
                                                   President and CEO


 STATE OF TEXAS           )
                          )
 COUNTY OF NUECES         )


        This instrument was acknowledged before me on the 17th day of October,
1996, by BENJAMIN J. GALLANT, as President and CEO of TEXAS AIRSONICS, INC., a
Texas corporation, on behalf of said corporation.



       DELMA LINDLEY                
       Notary Public                
SEAL   STATE OF TEXAS                                  Delma Lindley
       MY Comm. Exp. Feb. 19, 1997              -----------------------------
                                                 Notary Public, State of Texas


Return to:

The International Bank
P. O. Drawer 4956
Corpus Christi, Texas 78469

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