* Dual Phase Operation with Modulus(R) Calculation
* Differential or Single-Ended Input
* Gain Setting from 3μV to 1V
* Analogue Meter for Display of X, Y or R Output Signals
* X & Y Offset Controls
* Output Time Constants from 100μs to 30s
* 90° Step or Fine Phase Control
This analogue dual phase lock-in amplifier uses advanced technology to create a high performance instrument that is both versatile and easy to use.
Lock-in amplifiers are used to measure the amplitude and phase of signals buried in noise by using the process of synchronous detection to recover the signals.
The amplifier achieves this by acting as a narrow-bandpass filter that removes much of the unwanted noise while allowing through the signal that is to be measured.
The frequency of the signal to be measured and thus the passband region of the filter is set by a reference signal, which has to be supplied to the lock-in amplifier along with the unknown signal.
Jumper options within the unit allow the outer BNC contact or screen to act as a high impedance differential input, as a low impedance(100W) differential input or allow it to be connected to ground for single-ended operation.
Through the careful design of the lock-in, up to ±10V of DC offset is allowed before saturation for gain settings from 1V to 300μV, ±1V of DC offset for gain settings from 100μV to 10μV and ±300mV of DC offset for the gain setting of 3μV.
The output of the signal input stage is processed using two very high bandwidth demodulators each operating 90° apart from each other to produce the X and Y signals.
The X and Y outputs from the demodulator are passed through two first order, low pass filters and then amplified.
The Reference Channel input circuitry uses a phase locked loop to lock on to a range of signals, such as TTL pulses or sinusoidal waveforms. A phase shifting circuit allows the reference signal to be moved with relation to the signal input. Signals at both the reference frequency and twice the reference frequency can be monitored.
* 用計算法則來雙相位操作
* 一端輸入或訊號差的輸入
* 增益設定從 3μV 到 1V
* 類比儀顯示 X, Y 或 R 輸出訊號
* X & Y 平移控制
* 輸出時間常數由 100μs 到 30s
* 90° 步或精細相位控制
類比雙鎖相放大器使用進階技術來製造多樣性易使用的儀器. 鎖相放大器是用來量測 在雜訊中的訊號之振幅和相位 並藉著同步偵測來還原訊號.使用窄的帶通濾波器移除訊號中不需要的雜訊讓訊號易於量測. 可以量測訊號的頻率且將濾片的帶通範圍設為參考訊號, 可以與未知訊號一起提供到鎖相放大器中.
可選購跳接線外接BNC 或螢幕讓訊號差的輸入有高阻抗, 成為低阻抗(100W) 的訊號差的輸入或接地或單端操作. 經過鎖相之適當設計, 可達最大到 10V 的DC 平移 , 這是在增益飽和前由 1V 到 300μV, 1V 的 DC 平移量由 增益設定100μV 至 10μV 和 300mV 的 DC 平移量由 增益設定 3μV.
訊號輸入時的輸出程序是利用兩個高頻寬的解碼器, 其中之一運作在與另一個呈 90°來產生 X 和 Y 訊號. 由解碼器X和Y輸出會經由兩個一階的低通濾片後放大.
參考通道使用鎖相迴路不斷輸入鎖住訊號範圍, 比如 TTL 脈衝或正弦波形. 電路的相位移使得參考訊號相對輸入訊號作移動. 可同時監控參考頻率及其倍數的訊號.
