[LETTERHEAD OF BT ALEX. BROWN INCORPORATED]
 
                                          July 29, 1998
 
Board of Directors
ATL Ultrasound, Inc.
22100 Bothell Everett Highway
Bothell, Washington 98041
 
Members of the Board:
 
BT Alex. Brown Incorporated ("BT Alex. Brown") has acted as financial advisor to
ATL Ultrasound, Inc. ("ATL") in connection with the proposed merger transaction
involving ATL and Philips Electronics North America Corporation ("Philips")
pursuant to an Agreement and Plan of Merger, dated as of July 29, 1998 (the
"Merger Agreement"), among ATL, Philips and Philips Acquisition, Inc., a wholly
owned subsidiary of Philips ("Sub"), which provides, among other things, for (i)
the commencement by Sub of a tender offer to purchase all outstanding shares of
the common stock, par value $0.01 per share, of ATL (the "ATL Common Stock" and,
such tender offer, the "Tender Offer") at a purchase price of $50.50 per share,
net to the seller in cash (the "Cash Consideration") and (ii) subsequent to the
Tender Offer, the merger of Sub with ATL (the "Merger" and, together with the
Tender Offer, the "Transaction") pursuant to which each outstanding share of ATL
Common Stock not previously tendered will be converted into the right to receive
the Cash Consideration. The terms and conditions of the Transaction are more
fully set forth in the Merger Agreement.
 
You have requested BT Alex. Brown's opinion as to the fairness, from a financial
point of view, of the Cash Consideration to be received in the Transaction by
holders of ATL Common Stock (other than Philips and its affiliates).
 
In connection with BT Alex. Brown's role as financial advisor to ATL, and in
arriving at its opinion, BT Alex. Brown has reviewed certain publicly available
financial and other information concerning ATL and certain internal analyses and
other information furnished to it by ATL and/or its advisors. BT Alex. Brown has
also held discussions with members of the senior management of ATL regarding the
business and prospects of ATL. In addition, BT Alex. Brown has (i) reviewed the
reported prices and trading activity for ATL Common Stock, (ii) compared certain
financial and stock market information for ATL with similar information for
certain other companies whose securities are publicly traded, (iii) reviewed the
financial terms of certain recent business combinations which it deemed
comparable in whole or in part, (iv) reviewed the terms of the Merger Agreement,
and (v) performed such other studies and analyses and considered such other
factors as it deemed appropriate.
 
BT Alex. Brown has not assumed responsibility for independent verification of,
and has not independently verified, any information, whether publicly available
or furnished to it, concerning ATL, including, without limitation, any financial
information, forecasts or projections considered in connection with the
rendering of its opinion. Accordingly, for purposes of its opinion, BT Alex.
Brown has assumed and relied upon the accuracy and completeness of all such
information and BT Alex. Brown has not conducted a physical inspection of any of
the properties or assets, and has not prepared or obtained any independent
evaluation or appraisal of any of the assets or liabilities, of ATL. With
respect to the financial forecasts and projections made available to BT Alex.
Brown and used in its analyses, BT Alex. Brown has assumed that they have been
reasonably prepared on bases reflecting the best currently available estimates
and judgments of the management of ATL as to the matters covered thereby. In
rendering its opinion, BT Alex. Brown expresses no view as to the reasonableness
of such forecasts and projections or the assumptions on which they are based. BT
Alex. Brown's opinion is necessarily based upon economic, market and other
conditions as in effect on, and the information made available to it as of, the
date hereof.
 
For purposes of rendering its opinion, BT Alex. Brown has assumed that, in all
respects material to its analysis, the Transaction will be consummated on the
terms and subject to the conditions described in the

Board of Directors
ATL Ultrasound, Inc.
July 29, 1998
Page 2
 
Merger Agreement and that all conditions to the consummation of the Transaction
will be satisfied without any waiver thereof.
 
This opinion is addressed to, and for the use and benefit of, the Board of
Directors of ATL and is not a recommendation to any shareholder as to whether or
not such shareholder should tender shares of ATL Common Stock in the Tender
Offer or how such shareholder should vote on the proposed Merger. This opinion
is limited to the fairness, from a financial point of view, of the Cash
Consideration to be received in the Transaction by the holders of ATL Common
Stock (other than Philips and its affiliates), and BT Alex. Brown expresses no
opinion as to the merits of the underlying decision by ATL to engage in the
Transaction.
 
BT Alex. Brown, as a customary part of its investment banking business, is
engaged in the valuation of businesses and their securities in connection with
mergers and acquisitions, negotiated underwritings, private placements and
valuations for estate, corporate and other purposes. BT Alex. Brown will receive
a fee for its services as financial advisor to ATL in connection with the
Transaction, a significant portion of which is contingent upon the consummation
of the Transaction and a portion of which is payable upon the delivery of this
opinion. BT Alex. Brown also acted as financial advisor to ATL with respect to
the spin-off in April 1998 of SonoSight, Inc., formerly a business division of
ATL, for which services BT Alex. Brown has received compensation. BT Alex. Brown
maintains a market in ATL Common Stock and regularly publishes research reports
regarding the medical device and equipment industry and the businesses and
securities of ATL and other publicly owned companies in the medical device and
equipment industry. In the ordinary course of business, BT Alex. Brown and its
affiliates may actively trade or hold the securities and other instruments and
obligations of ATL and Philips or their respective affiliates for their own
accounts and for the accounts of their customers and, accordingly, may at any
time hold a long or short position in such securities, instruments and
obligations.
 
Based upon and subject to the foregoing, it is BT Alex. Brown's opinion that, as
of the date of this letter, the Cash Consideration to be received in the
Transaction by the holders of ATL Common Stock (other than Philips and its
affiliates) is fair, from a financial point of view, to such holders.
 
                                          Very truly yours,
                                          /s/ BT Alex. Brown Incorporated
 
                                          BT ALEX. BROWN INCORPORATED
 
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