25kHz—200MHz频率范围, 100s -30ks时间常数；6，12，18，24dB/倍频程衰减,

 内部或外部参考源；自动量程；存储和调用9个仪器设备, 标准GPIB，RS—232接口

The SR844 is the widest bandwidth lock-in amplifier available. It provides uncompromised performance with a frequency range of 25 kHz to 200 MHz and up to 80 dB of drift-free dynamic reserve. It includes the many features, ease of operation, and programmability that you&＃39;ve come to expect from SRS DSP lock-in amplifiers.