The Signal Recovery model 7225 offers a cost-effective solution to the researcher needing the performance provided by DSP demodulation but not requiring the additional features or higher operating frequencies of the models 7280 and 7265.
The instrument performs all of the normal measurements of a dual phase lock-in amplifier, measuring the in-phase and quadrature components, vector magnitude, phase angle and noise of the input signal.
Two auxiliary ADC inputs, four DAC outputs and eight output logic lines are provided. These can be used to record the magnitude of external signals associated with the experiment, such as temperature or pressure, or to generate voltages to control or switch other equipment. Information from the ADCs together with the lock-in amplifier’s output data can be stored in the 32k point buffer memory prior to transfer back to a controlling computer.
The model 7225 is extremely easy to use. All instrument controls are adjusted via the left-hand display panel and its associated keys, while the right hand panel shows the two selected instrument outputs. Auto functions need only two keypresses to activate and in many cases eliminate the need for manual control adjustment. External control of the unit is via either the RS232 or GPIB interfaces, using simple mnemonic-type ASCII commands. A second RS232 port allows up to sixteen 7225 or compatible instruments to be operated from a single RS232 computer port by connecting them in a “daisy-chain” configuration.