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92B

1280

Instruction Manual

Millivoltmeter

TEL: 201- 887-5110 l TWX: 710-986-8241

499 POMEROY ROAD, PO BOX 122 PARSIPPANY, N. J. 07054

TABLE OF CONTENTS

CHAPTER

I INTRODUCTION

1.1 GENERAL

1.2 EQUIPMENT DESCRIPTION

1.2.1 Frequency Capability

1.2.2 Voltaqe Capability

1.2.3 True RMS Response

1.2.4 Low Noise

1.2.5 Minimal Zero Adjustment

1.2.6 DC Output

II SPECIFICATIONS

III OPERATION

3.1 IIXSTALLATION

3.1.1 Operating Controls and Indicators

3.2 OPERATING PROCEDURES

3.2.1 Initial Operating Procedure

3.3 OPERATING NOTES

3.3.1 Overload Limits

3.3.2 Connection for Measurements Below 100 MHz

3.3.3 Connection for Measurements Above 100 MHz

3.3.4 Low-Level Measurement

3.3.5 Making the Zero Adjustment

3.3.6 Signal Overload on 1 mV Range

3.3.7 Temperature Effects

3.3.8 Hum, Noise, and Spurious Pickup

3.4 DC OUTPUT

3.5 LOW FREQUENCY MEASUREMENTS

3.6 CORRECTION CURVE FOR MODEL Pl-8B, 50 OHM ADAPTER

3.7 CORRECTION CURVE FOR MODEL Pl-14A, 50 Otll\l TEE ADAPTER

IV THEORY OF OPERATION

4.1 GENERAL

4.1.1 RF Probe

4.1.2 Attenuator and Amplifiers

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TARI,E OF CONTENTS (CONT INUW)

CHAPTER -__-- PAr;t. --._-

',' I

4.1.3 C~ynchro~~ous Detector

4.1.4 Shaping Amplifier

4.1.5 Chopper-Driver Circuits

4.1.6 Power Supply

4.1.7 Programming

MAINTENANCE 22

5.1 PERIODIC CALIBRATION 22

5.2 PRECAUTIONS WIIEN CIIECKING CALIBRATION 22

5.3 CALIBRATION CflECK 23

5.4 CALIBRATIO~J PROCEDURE 23

5.5 TROUBLESHOOTING PROCEDURE 25

5.5.1 Cover Removal 25

5.5.2 Chopper Replacement 25

5.5.3 VOltSJe and KesiStanCe Tests 25

5.5.4 Test Points 26

5.5.5 Replacement of RI‘ Probes 2 F,

5.5.6 Probe Tests 26

INTERFACE 32

6.1 INPUT CHARACTERISTICS 32

6.2 INPUT PULL-UP 33

6.3 ANtALCG OUTPUT 33

Inpu t Resistance of RF Probe as a Function of Input Leve 1 and Frequency 10

Input Capacitance vs Input Level of Zlodel 91-12F Probe (Pleasured at 10 MHz1 11

Typical SWR of Model 91-12F RI Probe with Model 91-8B 50 c Adapter 11

Typical SWR of Model 9l-12F RF Probe with Model 91-14A Type N Tee Adapter

CIIARTS AND DRAWINGS

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and Model 91-15A 50 :2 Termination 11

Assembly of I.lodel 91-14A Type N Tee Adapter 15

Model 91-8B 50 9 BNC Adapter Correction Curve ia

Model 91-14A Type N Tee Adapter Correction Curve 18

Block Diagram 19

Calibration Instructions 24

Frequency Response Test Setup 30

ii

a.“* CHARTS AND DRAWINGS (CONTINUED)

FIGURE NO. -__ ---

10 Swept Frequency Response Test Setup

11 Pin Designations

12 External Connections

SCHEMATICS

TABLES

Required Accessories

Crest I‘actors

Model 920 Controls and Indicators

Connection Recommendations

TABLE OF REPLACEABLE PARTS

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Endpapers

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CFtAPT-ER I

1iJTRODUCTIO:S

The Model 92 exhibits true rms response for input signals up to 30 millivolts, gradually

approaching peak-to-peak above this level. The meter, however, is calibrated to indicate

nns of a sine wave above 30 mV.

Input and output connections for external control and readou t are provided by a 22-pin

sard-eL1<lc connector at the rear of the instrument.

1.1 GENERAL

The Elodcl 92 Series RF Millivoltmeter provides an accurate readout of measurements from the

low radio frequencies to the gigahertz region, over a voltage range of 200 UV to 3 volts.

It is a proqrammable, solid-state instrument of high sensitivity and accuracy, characterized

by Iliqh input impedance (see Figures 1 and 2), excellent stability, and low noise.

;i linear dc output, whose level is proportional to the rf input voltage, is also provided

.it a rear connector. This may be used to drive a recorder, remote indicator, or other analog

.levices.

The 92 offers a convenient and accurate means for making a wide variety of measurements.

T:,I;ical uses of this instrument include:

In transistor testing the instrument may be used to measure 0, ft, and other transistor

parameters.

SWR and return loss measurement using the Model 92 Series with bridge methods, directional

couplers, and adjustable or slotted lines.

~aln and loss measurements in wide-band amplifiers, including such design characteristics

is stage qain, flatness of the pass band, upper cut-off or corner frequency, negative feedback

factors, and other parameters.

Proper adjustment of tuned circuits in narrow-band amplifiers.

The adjustment, measurement of performance, and evaluation of rf filter parameters.

92c

1280 1