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home > Products > Measurement Instruments > Lock-in Amplifier/Preamplifier > Lock-in Amplifier > LI5660/LI5655/LI5650/LI5645 > Features
Product Information
Lock-in Amplifier/Preamplifier
Digital Lock-in Amplifier
LI5660/LI5655/LI5650/LI5645

High-response and High-stability
Time Constant Time Constant Setting
Time Constant
 

The minimum time constant is 1 μs for LI5660/LI5655 (5 μs for LI5650/LI5645).
Our newest lock-in amplifiers have achieved high-frequency and high speed response.



Outstanding Dynamic Reserve
 

Phase detection and subsequent processing are performed digitally. Output zero drift at high gains is smaller than the analog system, and up to 100 dB dynamic reserve can be obtained (measurement can be performed with a noise 100,000 times larger than the sensitivity, namely the signal full scale).



Up to 11 MHz with the wide-band, high-frequency (LI5660)
Voltage measurements can be made with a single end (A) or differential (A-B) input, as well as 10 Vrms input (C) and high-frequency input (HF) terminals with the LI5660. The HF input terminals can be used to measure up to 11 MHz.


Fractional Harmonic Measurements
In addition to the frequency of the reference signal, its harmonic content can also be measured.
Harmonics can be set not only for integers, but also for fractions in the range of (1 to 63) / (1 to 63).
Fractional Harmonic Setting
Fractional Harmonic
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Dual-frequency Simultaneous Measurements (LI5660/LI5655/LI5650)
Dual-phase (Rcosθ, Rsinθ), Dual PSDs (Primary PSD, Secondary PSD)
A lock-in amplifier equipped with a dual-phase high-sensitivity detector (PSD) can simultaneously measure dual frequency components contained in an input signal. A general-purpose lock-in amplifier requires two units, but one unit can measure dual frequencies.

Dual frequency settings can be set for external reference signals and their calculations, or for internal oscillator signals and their calculations. By using this function together with the fraction setting for harmonic measurement, mutual interference during dual frequency measurement can be reduced. For example, if the harmonic measurement frequency is set to a fraction of a prime number, the influence of harmonics equal to or less than the multiplication value of the set prime number can be eliminated.
Detection Mode (Dual 1)
Detection Mode (Dual 1)
Detection Mode
Primary PSD
Secondary PSD
Function
SINGLE* Fundamental / Fractional Harmonic None 2-phase detection is at one frequency.
DUAL1 Fundamental / Fractional Harmonic Fundamental / Harmonic Simultaneous measurement of the fundamental wave and its harmonic components included in a single input signal
DUAL2 Primary Frequency Secondary Frequency
Simultaneous measurement of two individual harmonic components included in a single input signal
CASCADE Primary Frequency Secondary Frequency The secondary PSD is connected in cascade to the primary PSD.
*The detection mode of LI5645 is "SINGLE" mode only.


Low Frequency Measurement
Synchronous Filter
 

This is an integer-period moving-average filter. Ripple caused by detection is greatly reduced, and the output is nearly settled in the averaging interval (integer period), so the time constant can be reduced (to obtain faster response).

High-speed Locking Even at Low Frequencies

  It takes just about two cycles to lock on to the reference signal even at low frequencies. Furthermore, a moving average filter synchronized with the signal cycle obtains a high-speed response with a small ripple.
Display and Sampling of Output Data

 High Speed Sampling of Analog Data

The digital data of output is sampled at high speed and converted to an analog signal.

  • LI5660/LI5655: up to approximately 1.5 M samples/s
  • LI5660/LI5655: up to approximately 1.5 M samples/s

It is useful to detect peak signals when measuring by differential calculus such as Auger electron spectroscopy.

 

 Digital Data Buffer Function

If the number of data points is large in high-speed measurement, it may not be possible to transfer all data due to the communication speed of the interface.
NF's lock-in amplifier has a data buffer function that temporarily stores digital data. By temporary storing the measurement data in a buffer and transferring the data sequentially, a large amount of data can be transmitted without loss.



External 10 MHz Synchronization
Synchronizing operation of other devices such as a signal generator and the LI5600 series using a 10 MHz frequency source allows synchronization to any frequency (can be configured) without having to use an external reference signal (REF IN). External 10 MHz Reference Input Setting
External 10 MHz Reference Input

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Wide Range of Functions in a Thin, Compact Body
LI5660
Front Panel of LI5660
Rear panel of LI5660


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