Exhibit 99.1

Symmetricom Reports First Quarter Fiscal Year 2014 Financial Results

October 21, 2013

Contact:

Justin Spencer

Chief Financial Officer

+1-408-428-7801

jspencer@symmetricom.com

Symmetricom Reports First Quarter

Fiscal Year 2014 Financial Results

Enters Proposed Transaction with Microsemi Corporation

SAN JOSE, Calif. — October 21, 2013 — Symmetricom, Inc. (NASDAQ:SYMM), a worldwide leader in precision time and frequency technologies, today reported financial results for its first quarter of fiscal year 2014 ended September 29, 2013.

In a separate announcement earlier today, Symmetricom and Microsemi Corporation announced that they have entered into a definitive agreement whereby Microsemi will acquire Symmetricom for $7.18 per share, in a transaction valued at approximately $230 million, net of Symmetricom’s projected cash balance at closing. As a result of this pending transaction Symmetricom has accelerated the release of its first quarter fiscal 2014 earnings, suspended its prior practice of providing quarterly financial guidance and cancelled its conference call to discuss first quarter fiscal 2014 results scheduled for Tuesday, October 22, at 1:30 p.m. Pacific Time.

Net revenue for the first quarter of fiscal 2014 was $48.0 million, compared to $56.4 million reported for the first quarter of fiscal 2013. Symmetricom reported a net loss of $1.0 million, or $0.02 per share, for the first quarter of fiscal 2014, compared to net loss of $0.2 million, or $0.01 per share, in the first quarter of fiscal 2013.

Non-GAAP net income for the first quarter of fiscal 2014 was $0.9 million, or $0.02 per share, compared to $1.6 million, or $0.04 per share, reported for the first quarter of fiscal 2013.

Cash, cash equivalents and short-term investments totaled $79.8 million as of September 29, 2013 compared to $75.5 million reported as of June 30, 2013. Net cash provided by operating activities in the first quarter was $4.3 million, and property, plant and equipment purchases were approximately $1.6 million, resulting in free cash flow of $2.7 million.

“We made significant progress executing our business plan in the quarter, as we delivered results in-line with our expectations,” said Liz Fetter, Chief Executive Officer of Symmetricom.

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Business Segment Revenue Results

Revenue in the Communications Business in the first quarter of fiscal 2014 was $23.6 million, compared to $31.4 million reported in the first quarter of fiscal 2013. Revenue in the Government and Enterprise Business in the first quarter of fiscal 2014 was $24.5 million, compared to $25.0 million reported in the first quarter of fiscal 2013.

About Symmetricom, Inc.

Symmetricom (NASDAQ:SYMM), a world leader in precise time solutions, sets the world’s standard for time. The Company generates, distributes and applies precise time for the communications, aerospace/defense, IT infrastructure and metrology industries. Symmetricom’s customers, from communications service providers and network equipment manufacturers to governments and their suppliers worldwide, are able to build more reliable networks and systems by using the Company’s advanced timing technologies, atomic clocks, services and solutions. All products support today’s precise timing standards, including GPS-based timing, IEEE 1588 (PTP), Network Time Protocol (NTP), Synchronous Ethernet and DOCSIS^® timing. Symmetricom is based in San Jose, California, with offices worldwide. For more information, visit: http://www.symmetricom.com or join the dialogue at http://www.twitter.com/symmetricom.

Important Information and Where To Find It

The transaction referred to above will be effected through a tender offer which has not yet commenced. No statement in this document is an offer to purchase or a solicitation of an offer to sell any shares of the common stock of Symmetricom or any other securities. At the time the Offer is commenced, Microsemi Corporation (“Microsemi”) and PETT Acquisition Corp., a wholly owned subsidiary of Microsemi, will file a tender offer statement on Schedule TO with the United States Securities and Exchange Commission (the “SEC”), and Symmetricom will file a Solicitation/Recommendation Statement on Schedule 14D-9 with the SEC. Any offers to purchase or solicitations of offers to sell may be made only pursuant to such tender offer statement. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ BOTH THE TENDER OFFER STATEMENT (INCLUDING AN OFFER TO PURCHASE, A LETTER OF TRANSMITTAL AND RELATED DOCUMENTS) AND THE SOLICITATION/RECOMMENDATION STATEMENT REGARDING THE OFFER WHEN THEY BECOME AVAILABLE, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION. These materials, when prepared and ready for release, will be made available to Symmetricom’s stockholders at no expense to them. In addition, investors and security holders may obtain a free copy of such materials (when available) and other documents filed with the SEC at the website maintained by the SEC at www.sec.gov or by directing such requests to the Information Agent for the tender offer, which will be named in the tender offer statement.

Non-GAAP Information

Certain non-GAAP financial information is included in this press release. In the reconciliation of GAAP to non-GAAP results, Symmetricom excludes certain items related to non-cash equity-based compensation, acquisition-related costs, amortization of intangible assets, restructuring charges, executive transition costs and off-shore development transition costs that the Company does not consider indicative of its ongoing performance. The income tax effect after these non-GAAP adjustments is determined based upon Symmetricom’s estimate of its annual non-GAAP effective tax rate excluding these non-GAAP adjustments. Symmetricom believes that excluding such items provides investors, analysts and management with a representation of the Company’s core operating performance and with information useful in assessing, in conjunction with GAAP results, underlying trends in operating performance. Management uses such non-GAAP information to evaluate financial results and to establish operational goals. Non-GAAP information should not be considered superior to or as a substitute for data prepared in accordance with GAAP. A reconciliation of the non-GAAP results to the GAAP results is provided in the financial schedules portion of this press release.

Free cash flow is defined as net cash provided by or used in operating activities minus purchases of property, plant and equipment. Symmetricom believes this metric provides useful information to its

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investors, analysts, and management about the level of cash generated by or used in normal business operations, including the use of cash for the purchase of property, plant and equipment. Management also views it as a measure of cash available to pay debt and return cash to stockholders. Free cash flow is not a GAAP financial measure and should not be considered superior to or a substitute for operating cash flow or other cash flow data prepared in accordance with GAAP.

Safe Harbor

This press release contains forward-looking information within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, and is subject to the safe harbor created by those sections. These forward-looking statements include statements concerning the expected closing of the acquisition, and future performance and growth as well as the information regarding the usefulness of the non-GAAP financial information. The statements in this press release are made as of the date of this press release, even if subsequently made available by Symmetricom on its website or otherwise. Symmetricom expressly disclaims any obligation to update or revise any forward-looking statement contained herein, whether as a result of a change in its expectations, a change in any events, conditions or circumstances on which a forward-looking statement is based, or otherwise. Symmetricom’s actual results could differ materially from those projected or suggested in these forward-looking statements. Factors that could cause future actual results to differ materially from the results projected in or suggested by such forward-looking statements include, but are not limited to, risks associated with uncertainties as to the timing of the tender offer and the subsequent merger; uncertainties as to how many of Symmetricom’s stockholders will tender their shares of common stock in the tender offer; the possibility that competing offers or acquisition proposals will be made; the possibility that various conditions to the consummation of the offer or the merger may not be satisfied or waived, including that a governmental entity may prohibit, delay or refuse to grant approval for the consummation of the offer or the merger; the effects of disruption from the transactions on Symmetricom’s business and the fact that the announcement and pendency of the transactions may make it more difficult to establish or maintain relationships with employees, suppliers and other business partners; the risk that stockholder litigation in connection with the tender offer or the merger may result in significant costs of defense, indemnification and liability; and other risks and uncertainties pertaining to the business of Symmetricom, including, the extent and magnitude of customer orders received and shipped within the same quarter, risks relating to general economic conditions in the markets we address and the telecommunications and government markets in general, risks related to the development of our new products and services, reliance on our contract manufacturer, the effects of increasing competition and competitive pricing pressure, uncertainties associated with changing intellectual property laws or misappropriation of intellectual property, developments in and expenses related to litigation, the inability to obtain sufficient amounts of key components, the rescheduling or cancellation of key customer orders, the loss of a key customer, the effects of new and emerging technologies, the risk that excess inventory may result in write-offs, price erosion and decreased demand, fluctuations in the rate of exchange of foreign currency, changes in our effective tax rate, market acceptance of our new products and services, technological advancements, undetected errors, design flaws, defects in our products or start-up manufacturing difficulties, the risks associated with our international sales, potential short-term investment losses and other risks due to credit market dislocation, geopolitical risks and risk of terrorist activities, the risks associated with attempting to integrate other companies and businesses we acquire, and the risk factors listed from time to time in Symmetricom’s reports filed with the Securities and Exchange Commission, including the annual report on Form 10-K for the fiscal year ended June 30, 2013 and subsequent Forms 10-Q and 8-K.

SYMM-F

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October 21, 2013

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SYMMETRICOM, INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except per share amounts)

(unaudited)

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October 21, 2013

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SYMMETRICOM, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(In thousands)

(unaudited)

Symmetricom Reports First Quarter Fiscal Year 2014 Financial Results

October 21, 2013

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SYMMETRICOM, INC.

RECONCILIATION OF GAAP TO NON-GAAP RESULTS

(In thousands, except per share amounts)

(unaudited)

Symmetricom Reports First Quarter Fiscal Year 2014 Financial Results

October 21, 2013

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SYMMETRICOM, INC.

RECONCILIATION OF GAAP TO NON-GAAP RESULTS

(In thousands, except per share amounts)

(unaudited)