Firmware Version 
The instructions in this manual apply to operation of a Model 7270 DSP Lock-in Amplifier that is fitted with 
Version 2.20 or later operating firmware. Users of instruments that are fitted with earlier firmware 
versions should update them to the current version free of charge by downloading an Update Pack from 
our website at www.signalrecovery.com The pack includes full instructions for use. 
 
Trademarks 
AMETEK® and the b® and a logos are registered trademarks of AMETEK, Inc 
Other product and company names mentioned are trademarks or trade names of their respective 
companies. 
 
Company Names 
SIGNAL RECOVERY is part of Advanced Measurement Technology, Inc, a division of AMETEK, Inc. It 
includes the businesses formerly trading as EG&G Princeton Applied Research, EG&G Instruments 
(Signal Recovery), EG&G Signal Recovery and PerkinElmer Instruments (Signal Recovery).