DXA-005 Dual-channel Lock-in Amplifier

Overview

The DXA-005 dual-channel lock-in amplifier is the latest core technology product currently available with excellent high-performance and broadband measurement capability. The instrument is based on digital modulation technology, equipped with 1GSPS 16-bit digital-to-analog converter (DAC) and 14-bit analog-to-digital converter (ADC), and adopts the DSP platform architecture, which is capable of accurately and quickly detecting the effective signal components hidden in the strong noise.

With two independent and synchronized input channels, the DXA-005 is not only able to measure the amplitude and phase information of two input signals at the same time, but also reaches the international leading level in terms of key performance indicators such as measurement accuracy, operating frequency range, signal-to-noise ratio and dynamic reserve. In addition, the addition of multi-harmonic measurement, oscilloscope and spectrum analyzer functions, and PID control functions makes the DXA-005 widely applicable to a wide range of needs in the scientific research and industrial fields.

Input Channel

The DXA-005 is equipped with a low-noise analog front-end amplifier, capable of efficiently processing differential or single-ended signals with an equivalent input noise as low as 3nV/√Hz. The channel's input impedance can be selected from 50 Ω or 10M Ω, and the full-scale sensitivity range is from 1nV to 1V, with a dynamic range of more than 120dB. 

In addition, the signal input channel adopts a dual ADC design, taking into account the needs of high-speed and high-precision measurements. Users can choose between a high-speed 14-bit ADC (supporting DC to 400MHz band) or a high-precision 24-bit ADC (supporting DC to 100kHz band) according to the actual application scenario.

Output Signal Channel

Based on a 1GSPS 16-bit digital-to-analog converter (DAC), the DXA-005 is capable of generating sine wave signals over a frequency range of 1Hz to 400MHz  with adjustable DC bias. Under a 50Ω load, the signal amplitude ranges from 1 Vpp to 1.5 Vpp, and the DC bias range is ±1.5 Vdc. For external devices that require a bias voltage, such as electro-optical modulators, the DXA-005, with its excellent drive capability, can directly drive the device without the need for an additional level-shifting amplifier. The phase of the output signal is synchronized with the instrument's internal oscillator, and the phase offset can be set independently.

Reference Channel

The reference signal of the lock-in amplifier can be selected as a sine wave or square wave signal according to the user's actual needs, or the reference signal can be digitally synthesized inside the instrument. When the DXA-005 is set to internal reference signal mode, the instrument's internal high-precision oscillator and digital synthesis algorithm will generate a sine wave signal for multiplying with the input signal, and this internal reference signal is almost unaffected by phase noise.

The phase resolution of the internal reference signal can be as high as 1μdeg by the digital phase shifting technique.
When the DXA-005 operates in the external reference signal mode, it can accept a sine wave signal or  TTL  logic level as the external reference signal, and this signal will be locked by the internal digital phase-locked loop. Based on the frequency of the reference signal, the DXA-005 can detect the same frequency of the signal and its harmonics, up to the 65,535th harmonic of the fundamental frequency,  but the maximum harmonic frequency cannot exceed the upper limit of the measurement bandwidth of the instrument.

Digital Demodulator

The time constant of the DXA-005 can be flexibly set from 25ns to 4ks, and users can customize the time constant according to their needs. The filter steepening rate can be selected from 6 to 48 dB/oct in 8 steps. With digital modulation technology and advanced filter structure, the DXA-005 offers higher dynamic reserve (>120dB), more accurate phase (absolute phase error <1°), zero DC drift, and excellent quadrature performance than traditional analog lock-in amplifiers. In addition, the DXA-005 provides an optional synchronization filter that effectively eliminates the effects of reference signal harmonics, ensuring that the instrument accurately detects low-frequency signals while providing a fast response.

Communications Interface

The DXA-005 has USB2.0 (host and slave interfaces), 1000Mbps RJ45 network port and RS232 serial port. Through each communication interface, users can effectively use all the test functions of DXA-005 on the control computer, set up reasonable control parameters of the instrument and read the data measured by the instrument.

PC Software

DXA-005 also provides users with professional software, each demodulator, input channel and output channel of the lock-in amplifier can be configured through the schematic
block diagram or control panel, which is both professional and practical as well as simple and intuitive. The software has a clear numerical display and real-time display of waveforms, and the measurement results can be saved in a CSV file output for subsequent analysis by professional software, making the test easy to handle. In addition, we also fully support Python, MATLAB and LabVIEW multi-language application program interface(API).

Color Display Screen

The DXA-005 is equipped with a 5.6-inch, 640 x 480 resolution TFT color display, which serves as the main display interface of the instrument and allows full independent control of the instrument through the keyboard. On the display, users can flexibly view the demodulator's X, Y, R, θ and other parameters, and also configure a variety of basic settings such as filter constants, making operation intuitive and convenient.

Oscilloscope

Oscilloscope function with 4 signal channels, selectable signal input, reference input, signal output, auxiliary input and output signals, with a variety of triggering methods, for the user real-time display of time domain signals. Maximum 65536 sampling depth, adjustable sampling time 65us - 1s.

PID Controllers

The DXA-005 has a built-in independent 2-channel digital PID controller with a sampling rate of up to 4 MSPS, which is tightly coupled with a lock-in amplifier to control the amplitude, phase, frequency and other signals of the output signal according to the measured value of the demodulator, thus realizing the precise regulation of a variety of controlled quantities.

Parametric Scanner

The parameter scanner provides users with convenient and fast scanning for instantaneous plotting of frequency response, amplitude response and other curves, and offers single or cyclic scanning modes.

FFT Spectrum Analyzer

FFT spectrum analyzers analyze the frequency domain information of a signal based on the waveform captured by an oscilloscope. Depending on the sampling rate, the frequency resolution of the spectrum analyzer is approximately 1Hz - 15kHz.