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                                                           EXHIBIT 3.1


                              AMENDED AND RESTATED

                          CERTIFICATE OF INCORPORATION

                                       OF
                             NEXTLEVEL SYSTEMS, INC.
        (Pursuant to Sections 242 and 245 of the General Corporation Law
                            of the State of Delaware)

            The undersigned, Keith A. Zar, certifies that he is the Vice
President and General Counsel of NextLevel Systems, Inc., a corporation
organized and existing under the laws of the State of Delaware (the
"Corporation"), and does hereby further certify as follows:

            (1) The name of the Corporation is NextLevel Systems, Inc.

            (2) The Corporation's original Certificate of Incorporation was
filed with the Secretary of State of the State of Delaware on January 6, 1997.
The Corporation's original name was NextLevel Systems of Delaware, Inc. A
Certificate of Amendment was filed with the Secretary of State of the State of
Delaware on June 11, 1997.

            (3) This Amended and Restated Certificate of Incorporation, which
amends and restates the certificate of incorporation of the Corporation, was
duly adopted by unanimous stockholder written consent in accordance with
Sections 228, 242 and 245 of the General Corporation Law of the State of
Delaware (the "GCL").

            (4) Pursuant to Section 103(d) of the GCL, this Amended and Restated
Certificate of Incorporation shall become effective at 5:00 p.m. on July 25,
1997 (the "Effective Date").

            (5) The text of the Amended and Restated Certificate of
Incorporation of the Corporation is amended and restated to read in its entirety
as follows:


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            FIRST: The name of the Corporation is NextLevel Systems, Inc.

            SECOND: The address of the Corporation's registered office in the
State of Delaware is Corporation Trust Center, 1209 Orange Street in the City of
Wilmington, County of New Castle, Delaware 19801. The name of its registered
agent at such address is The Corporation Trust Company.

            THIRD: The purpose of the Corporation is to engage in any lawful act
or activity for which corporations may be organized under the GCL.

            FOURTH: The total number of shares of all classes of capital stock
which the Corporation shall have the authority to issue is 420,000,000 shares
divided into two classes of which 20,000,000 shares of par value $.01 per share
shall be designated Preferred Stock and 400,000,000 shares of par value $.01 per
share shall be designated Common Stock.

            A. Common Stock

            1. Dividends. Subject to the preferential rights, if any, of the
Preferred Stock, the holders of shares of Common Stock shall be entitled to
receive, when and if declared by the Board of Directors, out of the assets of
the Corporation which are by law available therefor, dividends payable either in
cash, in property, or in shares of Common Stock.

            2. Voting Rights. Except as otherwise required by law, at every
annual or special meeting of stockholders of the Corporation, every holder of
Common Stock shall be entitled to one vote, in person or by proxy, for each
share of Common Stock standing in such holder's name on the books of the
Corporation.

            3. Liquidation, Dissolution, or Winding Up. In the event of any
voluntary or involuntary liquidation, dissolution, or winding up of the affairs
of the 


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Corporation, after payment or provision for payment of the debts and
other liabilities of the Corporation and of the preferential amounts, if any, to
which the holders of Preferred Stock shall be entitled, the holders of all
outstanding shares of Common Stock shall be entitled to share ratably in the
remaining net assets of the Corporation.

            B. Preferred Stock

                  1. Issuance. The Board of Directors of the Corporation is
authorized, subject to limitations prescribed by law, to provide for the
issuance of shares of Preferred Stock of the Corporation from time to time in
one or more series, each of which series shall have such distinctive designation
or title as shall be fixed by the Board of Directors prior to the issuance of
any shares thereof. Each such series of Preferred Stock shall have such voting
powers, full or limited, or no voting powers, and such qualifications,
limitations or restrictions thereof, as shall be stated in such resolution or
resolutions providing for the issue of such series of Preferred Stock as may be
adopted from time to time by the Board of Directors prior to the issuance of any
shares thereof pursuant to the authority hereby expressly vested in it, all in
accordance with the laws of the State of Delaware.

                  2. Amendment. Except as may otherwise be required by law or
this Amended and Restated Certificate of Incorporation, the terms of any series
of Preferred Stock may be amended without the consent of the holders of any
other series of Preferred Stock or of any class of Common Stock of the
Corporation.

            FIFTH: The business and affairs of the Corporation shall be managed
by and under the direction of the Board of Directors. The Board of Directors may
exercise all such authority and powers of the Corporation and do all such lawful
acts and things as are not by statute or this Amended and Restated Certificate
of Incorporation directed or required to be exercised or done by the
stockholders.


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            A. Number of Directors. Except as otherwise fixed by or pursuant to
the provisions of this Amended and Restated Certificate of Incorporation
relating to the rights of the holders of Preferred Stock to elect directors
under specified circumstances, the number of directors shall be fixed from time
to time exclusively by the Board of Directors pursuant to a resolution adopted
by a majority of the then authorized number of directors of the Corporation, but
in no event shall the number of directors be fewer than three. No director need
be a stockholder.

            B. Classes and Terms of Directors. The directors shall be divided
into three classes (I, II and III), as nearly equal in number as possible, and
no class shall include less than one director. The initial term of office for
members of Class I shall expire at the annual meeting of stockholders in 1998;
the initial term of office for members of Class II shall expire at the annual
meeting of stockholders in 1999; and the initial term of office for members of
Class III shall expire at the annual meeting of stockholders in 2000. At each
annual meeting of stockholders beginning in 1998, directors elected to succeed
those directors whose terms expire shall be elected for a term of office to
expire at the third succeeding annual meeting of stockholders after their
election, and shall continue to hold office until their respective successors
are elected and qualified. In the event of any increase in the number of
directors fixed by the Board of Directors, the additional directors shall be so
classified that all classes of directors have as nearly equal numbers of
directors as may be possible. In the event of any decrease in the number of
directors, all classes of directors shall be decreased equally as nearly as may
be possible, but in no case will a decrease in the number of directors shorten
the term of any incumbent director.

            C. Newly-Created Directorships and Vacancies. Subject to the rights
of the holders of any series of Preferred Stock then outstanding, newly created
directorships resulting from any increase in the number of directors or any
vacancies in the Board of 


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Directors resulting from death, resignation, retirement, disqualification,
removal from office or any other cause shall be filled only by a majority of the
directors then in office, even if less than a quorum is then in office, or by
the sole remaining director, and shall not be filled by stockholders. Directors
elected to fill a newly created directorship or other vacancies shall hold
office for the remainder of the full term of the class of directors in which the
new directorship was created or the vacancy occurred and until such director's
successor has been elected and has qualified.

            D. Removal of Directors. Subject to the rights of the holders of any
series of Preferred Stock then outstanding, the directors or any director may be
removed from office at any time, but only for cause, at a meeting called for
that purpose, and only by the affirmative vote of the holders of at least a
majority of the voting power of all issued and outstanding shares of capital
stock of the Corporation entitled to vote generally in the election of
directors, voting together as a single class.

            E. Rights of Holders of Preferred Stock. Notwithstanding the
foregoing provisions of this Article FIFTH, whenever the holders of any one or
more series of Preferred Stock issued by the Corporation shall have the right,
voting separately by series, to elect directors at an annual or special meeting
of stockholders, the election, term of office, filling of vacancies and other
features of such directorships shall be governed by the rights and preferences
of such Preferred Stock as set forth in this Amended and Restated Certificate of
Incorporation or in the resolution or resolutions of the Board of Directors
relating to the issuance of such Preferred Stock, and such directors so elected
shall not be divided into classes pursuant to this Article FIFTH unless
expressly provided by such rights and preferences.

            F. Written Ballot Not Required. Elections of directors need not be
by written ballot unless the By-laws of the Corporation shall otherwise provide.


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            SIXTH: To the fullest extent permitted under the law of the State of
Delaware, including the GCL, a director of the Corporation shall not be
personally liable to the Corporation or its stockholders for damages for any
breach of fiduciary duty as a director. No amendment to or repeal of this
Article SIXTH shall apply to or have any effect on the liability or alleged
liability of any director of the Corporation for or with respect to any acts or
omissions of such director occurring prior to such amendment or repeal. In the
event that the GCL is hereafter amended to permit further elimination or
limitation of the personal liability of directors, then the liability of a
director of the Corporation shall be so eliminated or limited to the fullest
extent permitted by the GCL as so amended without further action by either the
Board of Directors or the stockholders of the Corporation.

            SEVENTH: Each person who was or is made a party or is threatened to
be made a party to or is involved (including, without limitation, as a witness)
in any threatened, pending or completed action, suit, arbitration, alternative
dispute resolution mechanism, investigation, administrative hearing or any other
proceeding, whether civil, criminal, administrative or investigative
("Proceeding"), by reason of the fact that such person (the "Indemnitee") is or
was a director or officer of the Corporation or is or was serving at the request
of the Corporation as a director or officer of another corporation or of a
partnership, joint venture, trust or other enterprise, including service with
respect to an employee benefit plan, whether the basis of such Proceeding is
alleged action in an official capacity as a director or officer or in any other
capacity while serving as such a director or officer, shall be indemnified and
held harmless by the Corporation to the full extent permitted by law, as the
same exists or may hereafter be amended (but, in the case of any such amendment,
only to the extent such amendment permits the Corporation to provide broader
indemnification rights than said law permitted the Corporation to provide prior
to such amendment), or by other applicable law as then in effect, against all


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expense, liability, losses and claims (including attorneys' fees, judgments,
fines, excise taxes under the Employee Retirement Income Security Act of 1974,
as amended from time to time, penalties and amounts to be paid in settlement)
actually incurred or suffered by such Indemnitee in connection with such
Proceeding.

            EIGHTH: In furtherance and not in limitation of the powers conferred
by statute, the Board of Directors is expressly authorized to adopt, repeal,
alter, amend, or rescind the By-laws of the Corporation. In addition, the
By-laws of the Corporation may be adopted, repealed, altered, amended or
rescinded by the affirmative vote of the holders of at least a majority of the
voting power of all the issued and outstanding shares of capital stock of the
Corporation entitled to vote thereon.

            NINTH: The Corporation reserves the right to repeal, alter, amend or
rescind any provision contained in this Amended and Restated Certificate of
Incorporation, in the manner now or hereafter prescribed by statute, and all
rights conferred upon stockholders herein are granted subject to this
reservation.


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                  IN WITNESS WHEREOF, NextLevel Systems, Inc. has caused this
Amended and Restated Certificate of Incorporation to be signed by Keith A. Zar,
its Vice President and General Counsel, on this 25th day of July, 1997.


                                                NEXTLEVEL SYSTEMS, INC.


                                                By:  /s/ Keith A. Zar
                                                    ----------------------------
                                                    Name:  Keith A. Zar
                                                    Title: Vice President and
                                                           General Counsel