Chapter 1, INTRODUCTION 
1-3 
1.3 Key Specifications and Benefits 
The SIGNAL RECOVERY Model 7230 represents a further significant advance in 
the application of DSP technology in the design of a lock-in amplifier. 
Key specifications include: 
  Frequency range: 
  Standard unit      0.001 Hz to 120.000 kHz 
  With 7230/99 option    0.001 Hz to 250.000 kHz 
  Voltage sensitivity:      10 nV to 1 V full-scale 
  Current input mode sensitivities:  10 fA to 1 µA full-scale 
           10 fA to 10 nA full-scale 
  Line frequency rejection filter 
  Dual phase demodulator with X-Y and R- outputs 
  Very low phase noise of < 0.0001
°
 rms 
  Output time constant:      10 µs to 100 ks 
  5-digit output readings 
  Dual reference mode - allows simultaneous measurement of two signals at 
different reference frequencies 
  Single and dual harmonic mode - allows simultaneous measurement of up to two 
different harmonics of a signal 
  Tandem demodulation capability - suitable for double demodulation experiments 
that would otherwise require two lock-in amplifiers 
  Virtual reference mode - allows reference free measurements 
  Direct Digital Synthesizer (DDS) oscillator with variable amplitude and 
frequency 
  Oscillator frequency and amplitude sweep generator 
  Voltage controlled oscillator frequency or amplitude 
  8-bit programmable digital I/O port for external system control 
  Four configurable DAC outputs which can be used as analog signal outputs 
and/or as auxiliary DAC outputs 
  Four auxiliary ADC inputs 
  Full range of auto functions 
  Standard USB, Ethernet, and RS232 interfaces 
  100,000 point internal curve storage buffer