美国KROHN-HITE 3988滤波器
Krohn-Hite 3988 Butterworth / Bessel双通道滤波器是仔细设计的滤波器系列之一，提供易于操作，可靠性性高。
KH3988滤波器在低通模式下提供0.03Hz至1MHz的可调谐频率范围，在高通模式下提供0.03Hz至300kHz的可调谐频率范围。这两种模式都可以通过002选项扩展到0.003Hz。频率响应特性在频域中进行干净滤波，或者线性相位（Bessel）可以限度地平坦（Butterworth），以提供的脉冲滤波。
KH3988滤波器的每个通道是8极，宽范围，低通/高通滤波器或放大器，以0.1dB的步长提供70dB的增益。KH3988滤波器将接收0dB增益的 10V峰值的输入信号，并具有可选择的交流或直流耦合。过载检测器是标准配置，可帮助用户检测输入信号或不正确的增益设置。用于存储前面板设置的九十九组非易失性存储器存储在电池支持的CMOS中，可以通过简单的命令调用。
美国KROHN-HITE 3988滤波器，KH3988滤波器,可选功能应用于每个通道：
双通道
截止频率范围：0.03Hz至1MHz
衰减斜率：48dB /八度
可选择的过滤器模式：低通和高通
可选择的回应：Butterworth和Bessel
可选择的预过滤器和后过滤器增益
可选输入类型：差分和单端放大器（过滤旁路）模式
KROHN-HITE 3988，0.03Hz to 1MHz, Dual Channel，Butterworth/Bessel Programmable Filter
• Two Channel
• Cutoff Frequency Range: 0.03Hz to 1MHz
• Attenuation Slope: 48dB/Octave
• Filter Modes: Low-Pass and High-Pass
• Responses: Butterworth and Bessel
• Pre-Filter and Post-Filter Gains
• Input Type: Differential and Single-Ended
• Amplifier (Filter By-Pass) Mode
• GPIB Programmable
DESCRIPTION of KROHN-HITE 3988
The Krohn-Hite Model 3988 Butterworth/Bessel dual channel
filter is one of a family of filters carefully designed with the user in
mind, providing ease of operation, reliability and price
competitiveness.
The 3988 provides a tunable frequency range from 0.03Hz to
1MHz in the low-pass mode and 0.03Hz to 300kHz in the
high-pass mode. Both modes are extended down to 0.003Hz with
the 002 option. The frequency response characteristic is either
maximally flat (Butterworth) for clean filtering in the frequency
domain, or linear phase (Bessel) to provide superior pulse
filtering.
Each channel of the 3988 is an 8-pole, wide range,
low-pass/high-pass filter or an amplifier providing gains to 70dB
in 0.1dB steps. The 3988 will accept input signals of æ10V peak at
0dB gain and has selectable ac or dc coupling. Overload detectors
are standard and assist the user in detecting input signals or
incorrect gain settings. Ninety-nine groups of non-volatile
memory for storage of front panel set-ups are stored in
battery-backed CMOS which can be recalled with a simple
command.
BAND-PASS/BAND-REJECT OPERATION
With the Model 3988, the user can simply connect two channels in
series to achieve band-pass operation or two in summed parallel
for band-reject operation.
APPLICATIONS
Applications for the 3988 are ultra-sound measurements, random
noise testing, sound recording, suppressing interference in audio
communications and related fields of medical, geological,
geophysical, oceanographic, military and more. All these features
ａnd more are backed with the quality Krohn-Hite has provided in
filters since 1949.
SPECIFICATIONS
Specifications apply at 25°C, ±5°C.
FUNCTIONS (Each Channel)
Low-pass filter, high-pass filter, voltage gain amplifier.
FILTER MODE
Type: 8-pole, Butterworth/Bessel.
Attenuation: 48dB/octave.
Tunable Frequency Range fc: Low-pass, 0.03Hz to 1MHz;
high-pass, 0.03Hz to 300kHz; (option 002, 0.003Hz).
Frequency Resolution: 3 digits, 0.1Hz to max fc; 2 digits,
0.03Hz to 0.099Hz; (option 002, 1 digit, 0.003Hz to 0.009Hz;
2 digits, 0.01Hz to 0.099Hz).
Cutoff Frequency Accuracy: ±1%, 0.5Hz to 50kHz; ±2%,
50.1kHz to max fc; ±5%, 0.03Hz to 0.5Hz (option 002, ±5%,
0.003Hz to 0.5Hz).
Relative Gain at fc: –3dB, Butterworth; –12.6dB, Bessel.
High-Pass Bandwidth (0dB Gain): >4MHz.
