美國KROHN-HITE 3988濾波器
Krohn-Hite 3988 Butterworth / Bessel雙通道濾波器是仔細設計的濾波器系列之一，提供易于操作，可靠性性高。

KH3988濾波器在低通模式下提供0.03Hz至1MHz的可調(diào)諧頻率范圍，在高通模式下提供0.03Hz至300kHz的可調(diào)諧頻率范圍。這兩種模式都可以通過002選項擴展到0.003Hz。頻率響應特性在頻域中進行干凈濾波，或者線性相位（Bessel）可以限度地平坦（Butterworth），以提供的脈沖濾波。
KH3988濾波器的每個通道是8極，寬范圍，低通/高通濾波器或放大器，以0.1dB的步長提供70dB的增益。KH3988濾波器將接收0dB增益的 10V峰值的輸入信號，并具有可選擇的交流或直流耦合。過載檢測器是標準配置，可幫助用戶檢測輸入信號或不正確的增益設置。用于存儲前面板設置的九十九組非易失性存儲器存儲在電池支持的CMOS中，可以通過簡單的命令調(diào)用。



美國KROHN-HITE 3988濾波器，KH3988濾波器,可選功能應用于每個通道：

    雙通道
    截止頻率范圍：0.03Hz至1MHz
    衰減斜率：48dB /八度
    可選擇的過濾器模式：低通和高通
    可選擇的回應：Butterworth和Bessel
    可選擇的預過濾器和后過濾器增益
    可選輸入類型：差分和單端放大器（過濾旁路）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 ?10V 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.