Model 3944 Four Channel Programmable Filter

1Programmable filterdescription

Krohn-HiteModel 3944 Four Channel Programmable Filteris a4-channel Butterworth/Bessel filterProvide aProgrammable or desktop filtersCovering the cutoff frequency range from 3Hz to 2MHz, with a flat maximum (Butterworth) frequency response characteristic, it is used for clean filtering in the frequency domain or linear phase (Bessel) to provide excellent pulse or complex signal filtering. The passband gain is 1, and the attenuation slope of each channel is 24dB/octave. The 3944 model will accept input signals with a peak voltage of ± 4.5V and provide 0dB or 20dB input and output gains, which can be selected through the front panel keyboard or GPIB bus.

IIProgrammable filterconfiguration

Filters can be programmed and can be used inHigh pass or low-passThe Four ChannelsOperate in any combination; Two channels of any combination of bandpass or bandstop; Either the bandpass or bandstop of one channel or the high pass or low-pass of two channelsWhat combination. Four channels can be connected to achieve96dB/High pass or octave bandLow pass.

3、 Storage Settings

Model 3944 Four Channel Programmable FilterProvide users with99 Group non-volatile memory, used to store the frontBoard settings, stored in battery poweredCMOSIn the middle. Then it can be used simplyCommand call settings.3944 The model still provides self storage when powered on to its internal memoryCheck and diagnose to ensure that the equipment is working properly. If a malfunction occurs, the display screen willIndicate which oneROMorRAMA malfunction has occurred.

4Programmable filterapplication

3940 Type is applied in anti aliasing, random noise testing, sound measurement, recording,Suppress interference in audio communication circuits, etc.

5、 Instruction manual

Specification suitable for 25 ℃± 5 ℃

6、 Function

Low pass, high pass or bypass of four independent channels, bandpass or band stop of two channels.

7、 Filter characteristics (single channel)

Type:4-pole Butterworth (plane maximum) or Bessel (linear phase)

Frequency range (fc):3Hz at 2MHz

Frequency control:Keyboard input or up and down keys

Frequency resolution:1Hz from 3Hz to 1kHz; 10Hz to 2kHz, 100Hz to 100kHz; 1kHz to 1MHz; 10kHz to 2MHz.

Frequency accuracy (fc):± 2% from 20Hz to 500kHz at least significant digits (larger),; ± 5% at 2MHz,

Relative gain fc:Butterworth, -3dB; Bessel, -7.58dB

Bandwidth:DC to FC, DC coupling; 0.2Hz to fc, AC coupling (low-pass); FC to 10MHz (high pass).

Attenuation:Each channel has a frequency of 24dB/octave

Bandstop attenuation:> 80dB

Insertion loss (0dB input/output gain):± 0.5dB at 2MHz

8、 Input characteristics

Gain (pre filter):0dB or 20dB ± 0.2dB

Coupling:AC or DC

Impedance:1M Ω parallel 100pf

Signal peak (at 0dB gain):Peak voltage at fc<1MHz is ± 4.5V; peak voltage at 2MHz is ± 4V

Peak value of DC component:± 200V in communication coupling mode

9、 Output characteristics

Impedance:50Ω

Gain (post filter):0dB or 20dB ± 0.2dB

Voltage peak value:The peak voltage is ± 6.5V at ³ 500 Ω and ± 1.3V at ³ 50 Ω

Peak current:±25mA

Distortion:-80dB at 1kHz, 1Vrms

noiseUsing a 2MHz bandwidth detector<200 μ V

DC offset:Adjustable to 0V

DC stability:The typical value is ± 0.5mV/℃;The peak value is ±1mV/℃

10、 Conventional

Memory:99 optional groups; Memory is a non-volatile battery powered CMOS.

Self check diagnosis:When the MPU is powered on, it checks the unit and the display screen indicates the fault mode.

Display:7 paragraphs, green, LED； 0.3 inches high

Remote programming:IEEE-488.1 interface, including: SH1, AH1, T6, L4, SR1, RL1, PP1, DC1, DT0, C0, and E1.

Operating Temperature0 ℃ to 50 ℃

Chassis isolation:±200Vdc

Storage temperature:-20 ℃ to 70 ℃

Input/output interface:BNC， Panel and Rear Side

Power requirements:90-132/180-264V AC, 50Hz-400Hz, 40W.

Size and weight:3.5 inches (9cm) high, 14 inches (36cm) wide, and 12.5 inches (32.13cm) deep; 12 pounds (5.4kg) net weight, 14 pounds (6.3kg) total weight

Attachment:Three terminal power cord; Operation Manual

11、 Optional

020：The low-frequency cut-off range is from 0.3Hz to 200kHz

Rack installation kit:Part number RK-37 allows installation of model 3944 into a standard rack spacing of 19 feet.

Extended 1-year warranty:Part number EW3944

12、 Optional attachments

CAB-010：GPIB cable with connector, 2 meters

CAB-011：GPIB cable with connector, 1 meter

CAB-025：Cable, BNC，3ft， low noise

The manual is subject to change without prior notice.