OE1201 detects an input signal in a single-ended mode or a differential voltage mode. With an ultra low-noise preamplifier, the input noise is as low as 9 nV/√Hz@997 Hz.The input impedance is 10 MΩ and the full-scale inputvoltage sensitivity ranges from 1 nV to 1 V. Besides, OE1201 can be used for current measurement with gains of 106 or 108 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 OE1201 can keep a high dynamic reserve of 100 dB.
The reference signal can work in external mode or internal mode. In internal mode, a precise and stable internal oscillator generates 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°. OE1201 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 OE1201 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.
OE1201 has a 3.5-inch 320 x 240 color TFT-LCD. The measurement results of OE1201, such as X, Y, R, and θ, are shown in numerical form.
The internal oscillator of OE1201 generates a low distortion (–80 dBc) sine reference signal varying from 50 mHz to 120 kHz, which has a high frequency resolution of 1 mHz. The frequency and amplitude of the reference signal can be set by using the front panel of OE1201 or communication interface. When OE1201 is set in the external reference mode, the internal reference signal is phase-locked with the external reference signal.
OE1201 uses a high precision digital-to-analog converter (DAC) to output a sine wave signal at the same frequency as the internal reference signal. The amplitude and phase of the output sine wave can be set through the OE1201's display, where the maximum amplitude of the sine wave is 1 Vrms.
Users can use PC to control OE1201 through communication interfaces, including setting the parameters and reading the measurement data. OE1201 is equipped with a free LabVIEW program, which makes it easy to use in complex scientific experiments.