The Krohn-Hite Model 3901 programmable, two channel Elliptical filter/voltage gain amplifier is one of a family of new programmable filters from Krohn-Hite. It was carefully designed with the user in mind, providing ease of operation, reliability and price competitiveness. All backed with the quality which Krohn-Hite has provided in filters since 1949.
FILTER FEATURES
As an elliptical filter, the Model 3901 has two filter channels that have a tunable cutoff frequency range from 1Hz to 99kHz and a rolloff rate of 115dB/octave. Each channel can be used independently; one as a high-pass filter and the other as a low-pass filter; or the channels can be externally connected for band-pass (series) or band-reject (paralleled) operation. Each filter section has a minimum stopband attenuation of >80dB and a passband ripple of typically 0.22dB.
The 3901 provides either a single-ended or differential input with a common mode rejection of >60dB. Input gains to 40dB in 10dB steps and output gains to 20dB are also provided. The 3901 will accept input signals of ±10V peak at 0dB gain and has selectable ac or dc coupling. The filter is GPIB Bus programmable and is complimented with non-volatile memory for the storage of up to 99 front panel set-ups. Overload detectors are standard and assist the user in detecting excessive input signals or incorrect gain settings.
AMPLIFIER FEATURES
The 3901 is also a programmable voltage gain amplifier for applications that require a low noise amplifier. The amplifier has a bandwidth of 1MHz and gains to 60dB, selectable in 10dB steps, and a wideband noise of <100 V.
APPLICATIONS
Typical applications for the Model 3901 are: anti-aliasing in digital signal processing, separating specific bandwidths of information, enhancing signal-to-noise ratio, distortion testing, low noise pre-amplification and many more. Models offering other types of filters with different frequency ranges, slopes and number of channels are also available.
SPECIFICATIONS
FUNCTION
Two independent filter channels. Channel 1, high-pass or amplified by-pass; Channel 2, low-pass or amplified by-pass; one channel of band-pass or band-reject with external connections.
FILTER MODE
Type: 7-pole, 6-zero elliptical.
Attenuation: 115dB/octave.
Passband Ripple: 0.22dB typical, 0.4dB max.
Tunable Frequency Range fc: 1Hz to 99kHz.
Frequency Control: Keypad entry or increment, decrement keys.
Bandwidth:
High-Pass: fc to upper 3dB cutoff, >500kHz at 1Vrms with 0dB gain. Low-Pass: dc coupled, dc to fc; ac coupled, 0.32Hz to fc.
Relative Gain at fc Low-Pass: –0.22dB at 1.01fc nominal; High-Pass: –0.22dB at 0.99fc nominal.
Cutoff Frequency Accuracy: ±2%.
Frequency Resolution: 1Hz, 1Hz to 99Hz; 10Hz, 100Hz to 990Hz; 100Hz, 1kHz to 9.9kHz; 1kHz, 10kHz to 99kHz.
Stopband Attenuation: >80dB.
Stopband Frequency (fs): Low-Pass, 1.7fc; High-Pass, 0.59fc.
Insertion Loss: 0dB ±0.1dB.
Pre-Filter Gain: 0dB, 10dB, 20dB, 30dB, 40dB ±0.2dB.
Post-Filter Gain: 0dB, 10dB, 20dB ±0.2dB.
Input Coupling: ac or dc.
Wideband Noise (RFI): min. gain, 1kHz cutoff, <400 V, 99kHz cutoff, <1mV; Max. gain, <20 V.
Harmonic Distortion: –80dB at 1kHz.
Intermodulation Distortion: –80dB below full scale volts at 70kHz and 90kHz input frequency.
Spurious Components: –80dB below full scale with input source <50 ohms.
DC Stability: Typically ±10mV/ C.
Crosstalk Between Channels: –85dB below full scale with input source <50 ohms.
AMPLIFIER MODE (Each Channel)
Bandwidth: dc coupled, dc to >1MHz min gain, >400kHz max. gain; ac coupled, 0.32Hz to >1MHz min gain, >400kHz max gain.
Insertion Loss: 0dB ±0.05dB.
Gain: 10dB to 60dB in 10dB steps ±0.1dB.
Input: Differential or single-ended +(in phase), –(inverted).
CMRR: >60dB to 10kHz; approximately 50dB at 100kHz.
Sensitivity: 10mV peak with 60dB total gain for 10V peak output.
Maximum Input: ±10V peak at 0dB gain reduced in proportion to gain setting.
Impedance: 1 megohm in parallel with 100pf.
Coupling: ac or dc.
Maximum DC Component: ±100V in ac coupled mode.
Output:
Maximum Voltage (o.c.): 7Vrms to 200kHz; 3Vrms to 500kHz; 1Vrms to 1MHz.
Impedance: 50 ohms.
DC Offset: Adjustable to zero volts.
Harmonic Distortion (1V output): –80dB (0.01%) to 10kHz; –60dB (0.1%) to 100kHz..
Wideband Noise (referred to input, 2MHz BW detector): 100 V min. gain; 20 V max. gain.
DC Stability (RFI): Typically ±10mV/ C.
Crosstalk Between Channels: >85dB below full scale with input source <50 ohms.
GENERAL
Memory: 99 selectable groups; memory is non-volatile battery-backed CMOS.
Overload Modes: Three selectable modes; non-latching, that monitors all channels and displays the first channel to have an overload; latching, that maintains the overload display until it is cleared; and no indications.
Overload Indicators: LEDs for input and output. Gain display flashes when overload occurs on displayed channel.
Input Indicators: Green LEDs to indicate active input BNC.
Self-Test Diagnostics: MPU checks unit upon power-up. Display indicates failure mode.
Displays: 7 segment, green, LED; 0.3" high.
Remote Programming: IEEE-488.1 interface. Subsets: SH1, AH1, T6, L4, SR1, RL1, PP1, DC1, DT0, C0, E1.
Operating Temperature: 0 C to 50 C.
Isolation to Chassis: ±100Vdc.
Storage Temperature: –20 C to 70 C.
Input/Output Connectors: BNC, front and rear.
Power Requirements: 90-132/180-264 volts ac, 50Hz-400Hz, 40 watts.
Dimensions: 3.5" (9cm) high, 8.5" (21.8cm) wide, 18" (46.2cm) deep.
Weights: 12 lbs (5.4kg) net; 14 lbs (6.3kg) shipping.
Accessories: 6 foot, 3 terminal line cord; operating manual.
