SR570是一款低噪声电流前置放大器，能够
电流增益高达1 pA/V。高增益和带宽，
低噪音和许多方便的功能使SR570
适用于各种光子、低温和其他用途
测量。
获得
SR570的灵敏度设置范围为1 pA/V至1 mA/V
可以在1中选择−2.−5.顺序。微调增益
还提供了调整功能，允许您选择任何灵敏度
介于两者之间。
增益可以分配到放大器的各个阶段，以
优化仪器的性能。低噪声模式
将增益置于放大器前端，以获得*佳噪声
表演高带宽模式将增益分配给
改善频率响应的后期放大器
前端的。在低漂移模式下，输入放大器
替换为极低输入电流的运算放大器，降低了
仪器的直流漂移为1000倍。
过滤器
SR570包含两个一阶RC滤波器，其截止
频率和类型可以从前面板配置。
这些滤波器可以一起配置为6或12 dB/oct
衰减低通或高通滤波器，或作为6 dB/oct衰减带
通过过滤器。截止频率可在0.03 Hz至
1 MHz in a 1−3−10 sequence. A filter reset button is included to shorten the overload recovery time of the instrument when long filter time constants are used. Input Offset and DC Bias An input offset-current adjustment is provided to suppress any unwanted DC background currents. Offset currents can be specified from ±1 pA to ±1 mA in roughly 0.1 % increments. The SR570 also has an adjustable input DC bias voltage (±5 V) that allows you to directly sink current into a virtual null (analog ground) or a selected DC bias. Toggle and Blanking Two rear-panel, opto-isolated, TTL inputs provide additional control of the SR570. A blanking input lets you quickly turn off/on the instrument's gain which is useful in preventing front-end overloading. A toggle input inverts the sign of the gain in response to a TTL signal, allowing you to perform synchronous detection with a chopped signal. Battery Operated Three internal, rechargeable, lead-acid batteries provide up to 15 hours of battery powered operation. An internal battery charger automatically charges the batteries when the unit is connected to the line. The charger senses the battery state and adjusts the charging rate accordingly. Two rear-panel LEDs indicate the charge state of the batteries. When the batteries become discharged they are automatically disconnected from the amplifier circuit to avoid battery damage. No Digital Noise The microprocessor that runs the SR570 is "asleep" except during the brief interval it takes to change the instrument's setup. This ensures that no digital noise will contaminate your low-level analog signals. RS-232 Interface The RS-232 interface allows listen-only communication with the SR570 at 9600 baud. All functions of the instrument (except power on) can be set via the RS-232 interface. The RS-232 interface electronics are opto-isolated from the amplifier circuitry to provide maximum noise immunity