Lock-in amplifier DXA-002

signaldifferentialdigital

Input Channel DXA-002 detects an input signal in a single-ended mode or a differential voltage mode. With an ultra low-noise pre-amplifier, the input noise is as low as 9 nV/√Hz@997 Hz. The input impedance is 10 MΩ and the full-scale input voltage sensitivity ranges from 1 nV to 1 V. Besides, DXA-002 can be used for current measurement with gains of 10^6 or 10^8 V/A. Two line filters (50/60 Hz and 100/120 Hz) are designed to eliminate power frequency interference. A programmable gain amplifier is used to adjust the dynamic reserve of the system, so that DXA-002 can keep a high dynamic reserve of 120 dB. Reference Channel The reference signal can work in external mode or internal mode. In internal mode, a precise and stable internal oscillator generates a sine wave as an internal reference that is multiplied by the input signal. This internal signal is without any phase noise. With the digital phase-shifting technique, the phase resolution of the reference signal is 0.01 deg. DXA-002 can work at any fixed frequency from 50 mHz to 120 kHz in this mode. In external mode, the reference signal can be a sine wave or a TTL pulse or a square wave. The rising or falling edge of the external reference signal triggers the Phase Lock Loop (PLL) to lock the external signal. Based on the frequency of the reference signal, the DXA-002 can detect the harmonics of the input signal. The maximum harmonic signal frequency can reach 32,767 times the fundamental frequency, and the maximum harmonic frequency cannot exceed the maximum operating frequency of the instrument by 120 kHz.