Signal Recovery 7225

The Signal Recovery 7225 Dual Phase DSP Lock-In Amplifier offers a cost-effective solution to the researcher needing the performance provided by DSP demodulation. 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 Signal Recovery 7225 Dual Phase DSP Lock-In Amplifier 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.

Features and Specifications of the Signal Recovery 7225 Dual Phase DSP Lock-In Amplifier include:

• 0.001 Hz to 120 kHz operation
• Wide range of auxiliary inputs and outputs and user-upgradeable firmware
• Voltage and cur mode inputs
• Direct digital demodulation without down-conversion
• 10 μs to 100 ks output time constants
• Quartz crystal stabilized internal oscillator
• Synchronous oscillator output for input offset reduction
• Harmonic measurements to 32f
• Applications:
  • Chopped light measurements
  • AC bridge measurements
  • Audio studies
  • AC impedance studies
  • Vibration studies
  • Thermal wave detection