Krohn-Hite 3380 Series User manual

Model 3380 Series
Tunable Active Filter
Operating Manual
0.1Hz to 200kHz
48dB/Octave Slope
Butterworth and Bessel Response
Low-Pass, High-Pass, Band-Pass, Band-Reject
Model 3381 - Single Channel
Model 3382 - Dual Channel
Model 3384 - Four Channel

Model 3380 Series
0.1Hz to 200kHz (0.005Hz Optional)
1, 2 or 4 Channels, 48dB/Octave Slope
Low-Pass/High-Pass, Butterworth/Bessel Filter
Operating
Manual
Copyright©2004 Krohn-Hite Corporation. All rights reserved. Contents of
this publication may not be reproduced in any form without the written
permission of Krohn-Hite Corporation. Printed in USA - 9/2004.
15 Jonathan Drive, Unit 4,
Brockton, MA 02301-5566 - Made in U.S.A.
Tel: [phone]; Fax: [phone]
E-Mail: [email protected]

Service and Warranty
Krohn-Hite Instruments are designed and manufactured in accordance with sound engineering practices and should give
long trouble-free service under normal operating conditions. If your instrument fails to provide satisfactory service and
you are unable to locate the source of trouble, contact our Service Department at [phone], giving all the informa-
tion available concerning the failure.
DO NOT return the instrument without our written or verbal authorization to do so. After contacting us, we will issue a
Return Authorization Number which should be referenced on the packing slip and purchase order. In most cases, we will
be able to supply you with the information necessary to repair the instrument, avoiding any transportation problems and
costs. When it becomes necessary to return the instrument to the factory, kindly pack it carefully and ship it to us prepaid.
All Krohn-Hite products are warranted against defective materials and workmanship. This warranty applies for a period
of one year from the date of delivery to the Original Purchaser. Any instrument that is found within the one year warranty
period not to meet these standards, will be repaired or replaced. This warranty does not apply to electron tubes, fuses or
batteries. No other warranty is expressed or implied.
Krohn-Hite Corporation reserves the right to make design changes at any time without incurring any obligation to incor-
porate these changes in instruments previously purchased.
Modifications to this instrument must not be made without the written consent of an authorized employee of Krohn-Hite
Corporation.

Table of Contents
1.0 GENERAL DESCRIPTION ································1-1
1.1 INTRODUCTION ·········································1-1
1.2 SPECIFICATIONS ········································1-1
1.2.1 Functions (Each Channel) ·································1-1
1.2.2 Number of Channels · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 1-1
1.2.3 Filter Characteristics · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 1-1
1.2.4 General ···········································1-2
1.2.5 Options ···········································1-2
2.0 OPERATION········································2-1
2.1 INTRODUCTION ·········································2-1
2.2 TURN-ON PROCEDURE · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2-1
2.3 SELF TEST············································2-1
2.4 OPERATION ···········································2-1
2.4.1 Front Panel Controls and Display ·····························2-1
2.4.1.1 Channel Selection (Models 3382 and 3384 only) ·················2-1
2.4.1.2 Setting Cutoff Frequency ·····························2-1
2.4.1.3 Digit Select/Frequency Increment and Decrement ················2-2
2.4.1.4 Setting Input Gain (Pre-Filter) ····························2-2
2.4.1.5 Setting Output Gain (Post Filter) ···························2-2
2.4.1.6 Butterworth/Bessel Selection [TYPE] ·······················2-2
2.4.1.7 Low-Pass and High-Pass Operation – [MODE] ··················2-2
2.4.1.8 Variable Band-Pass Operation (Models 3382 and 3384 only) ··········2-2
2.4.1.9 Variable Band-Reject Operation (Models 3382 and 3384 only)··········2-3
2.4.1.10 AC/DC Coupling ·································2-3
2.4.1.11 Differential/Single-Ended Input··························2-3
2.4.1.12 Storing a Filter Setup [STORE] · · · · · · · · · · · · · · · · · · · · · · · · · 2-3
2.4.1.13 Recalling a Filter Setup [RECLL]· · · · · · · · · · · · · · · · · · · · · · · · · 2-3
2.4.1.14 Clear Entry Key – [CE] · ·····························2-3
2.4.1.15 All Channel Mode (Models 3382 and 3384) – [ALL CH] ·············2-3
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Table of Contents
(Continued)
2.5 REAR PANEL DC LEVEL ADJUSTMENTS ···························2-3
2.5.1 DC Level Adj (Rear Panel) Out · · · · ··························2-3
2.5.2 DC Level Adj (Rear Panel) HP ·······························2-3
2.6 FILTER CHARACTERISTICS ··································2-4
2.6.1 Amplitude Response · · ··································2-4
2.6.2 Phase Response ······································2-4
2.6.3 Group Delay········································2-4
2.6.4 Transient Response · · ··································2-5
3.0 INCOMING ACCEPTANCE ································3-1
3.1 INTRODUCTION ·········································3-1
3.2 TEST EQUIPMENT REQUIRED ·································3-1
3.3 CUTOFF FREQUENCY ACCURACY · · · · ··························3-1
3.4 STOPBAND ATTENUATION···································3-1
3.5 PRE-FILTER AND POST-FILTER GAIN ACCURACY ·····················3-2
3.6 NOISE CHECK ··········································3-2
3.7 COMMON MODE REJECTION ·································3-2
3.8 DISTORTION AND MAXIMUM SIGNAL CHECKS ·······················3-2
3.9 AC/DC COUPLING CHECK ···································3-2
4.0 CALIBRATION ······································4-1
4.1 INTRODUCTION·········································4-1
4.2 REQUIRED TEST EQUIPMENT·································4-1
4.3 CALIBRATION··········································4-1
4.3.1 DC Level ··········································4-1
4.3.2 100kHz Differential Input Adjustment ···························4-2
4.3.3 Unity Gain ·········································4-2
4.3.4 High Band Frequency Calibration ·····························4-2
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SECTION 1
GENERAL DESCRIPTION
1.1 INTRODUCTION
The Krohn-Hite Model 3380 Filter Series (3381, 3382 and 3384) are one, two or four channel filters providing a tunable
frequency range from 0.1Hz to 200kHz; and with the 002 option, the range is extended to 0.005Hz. The frequency re-
sponse characteristic is selectable to either maximally flat (Butterworth) for clean filtering in the frequency domain, or
linear phase (Bessel) to provide superior filtering of pulse or complex signals.
Each channel of the 3380 Series is a selectable low-pass or high-pass, 8-pole filter providing an input gain of up to 50dB
and an output gain of up to 20dB, selectable in 0.1dB steps. The 3380 Series will accept input signals of ±10V peak at
0dB gain and has selectable ac or dc coupling. Memory is available for storing set-ups of the instrument which can be re-
called later with a simple command. The following pages are the specifications of the Model 3380 Series Filters.
1.2 SPECIFICATIONS
1.2.1 Functions (Each Channel)
Low-pass filter, high-pass filter; 2 or 4 channel models, one or two channel(s) of band-pass or band-reject via external
connections.
1.2.2 Number of Channels
Model Channels
3381 1
3382 2
3384 4
1.2.3 Filter Characteristics
Type: Selectable 8-pole Butterworth or 8-pole Bessel.
Attenuation: 48dB/octave.
Tunable Frequency Range fc: 0.1Hz to 200kHz; (option 002, 0.005Hz).
Frequency Resolution: 3 digits, ³1Hz fc; 0.001Hz, <1Hz fc.
Cutoff Frequency Accuracy: ±3%.
Relative Gain at fc: –3.01dB, Butterworth; –12.59dB, Bessel.
Model 3380 Series Section 1 - General Description
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Passband Gain: ±0.2dB.
High-Pass Bandwidth (0dB Gain): >2MHz.
Stopband Attenuation: >100dB.
Maximum Input: ±10V peak at 0dB gain, reduced in proportion to gain setting.
Pre-Filter Gain: 0dB, 10dB, 20dB, 30dB, 40dB, 50dB, ±0.2dB.
Post-Filter Gain: 0dB to 20dB selectable in 0.1dB
steps, ±0.2dB.
Wideband Noise (2MHz bandwidth detector): 0dB gain, <400µVrms; Max input gain, <5µVrms RTI;
Max. gain <25µVrms RTI.
Harmonic Distortion (1V output): –60dB (0.1%) to 10kHz; –50dB (0.3%) to 200kHz..
Input: Differential or single-ended.
CMRR: >60dB to 10kHz; >50dB to 100kHz.
Sensitivity: 3mV peak with 70dB total gain for 10V peak output.
Impedance: 1 megohm in parallel with 25pf.
Coupling: ac (0.16Hz) or dc.
Maximum DC Component: ±100V in ac coupled mode.
Output:
Maximum Voltage (open circuit): ±10V peak.
Maximum Current: ±80mA peak.
Impedance: 50 ohms.
DC Offset: Adjustable to zero volts.
1.2.4 General
Crosstalk Between Channels: –80dB for fsig £200kHz, –70dB for fsig >200kHz with input source £50 ohms.
Memory: 9 stored set-ups (0 - 8).
Self-Test Diagnostics: MPU checks unit upon power-up. Display indicates failure mode.
Displays: 7 segment, green, LED; 0.3" high.
Operating Temperature: 0°C to 50°C.
Isolation to Chassis: ±200Vdc.
Input/Output Connectors: BNC.
Power: 3381, 9 watts; 3382, 16 watts; 3384, 30 watts.
Dimensions and Weights: 312“ (9cm) high, 14" (35.56cm) wide, 1212” (31.75cm) deep; 7 lbs (3.18kg) net, 9 lbs (4.09kg)
shipping.
1.2.5 Options
002: extends low end cutoff to 0.005Hz.
BK-330: Battery Option, up to 8 hours of operation, rechargable NiCad batteries (factory installation).
Section 1 - General Description Model 3380 Series
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