Bbk Electronics Bk Precision 1856D Users Manual Manual_040814_

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1

Instruction Manual

Model 1856D 3.7GHz Frequency Counter

2

WARRANTY

Warranty service covers a period of one year from the date of original purchase.

In case of technical failure within one year, repair service will be provided by our

service center or sales outlet free of charge.

We charge customers for repairs after the one-year warranty period has expired.

We charge for repairs regardless of the warranty period if failure resulted from the

user’s negligence, natural disaster or accident.

For more professional repair service, be sure to contact our service center or sales

outlet.

3

Introduction

Thank you for purchasing our product. Electronic measuring instruments

produced by us are high technology products made under strict quality control. We

guarantee their exceptional precision and utmost reliability. For proper use of the

product, please read this operation manual carefully.

Note

l To maintain the full precision and reliability of this product, use it within the

temperature range of 10 °C to 35 °C (50 oF to 95 oF), and within a humidity of

45% to 85%.

l After turning on the power, allow a warm up period of about 30 minutes before

use.

l This equipment should be used with a triple line power cord for safety.

l Due to ongoing product development and improvement, things such as exterior

design and technical specifications can change without prior notice.

l If you have further questions concerning use of this product, visit

www.bkprecision.com.

Safety Summary

Please take a moment to read these operating instructions thoroughly and

completely before operating this instrument. Pay particular attention to WARNINGS

concerning conditions and actions that pose a hazard to the user and CAUTIONS

describing conditions and actions that may damage the instrument.

l Before every use, inspect the instrument and other accessories for signs of

damage or abnormality.

l Keep your body isolated from ground.

l Never touch exposed wiring, connections or any live circuit conductors.

l Do not install substitute parts or perform any unauthorized modifications on the

instrument.

l Use caution when working above 60V DC or 30V AC rms. Such voltages pose

a shock hazard.

l Remember that line voltage is present on circuit points such as on-off switches,

fuse, power transformers, etc., even when the equipment is turned off.

l Remember that high voltage may appear at unexpected points in defective

equipment.

Safety Symbols

DANGEROUS VOLTAGE

AC-ALTERNATING CURRENT

DC-DIRECT CURRENT

SEE EXPLANATION IN MANUAL

GROUND

FUSE

4

CONTENTS

1. PRODUCT DESCRIPTION

1-1. Introduction -----------------------------------------------------

(5)

1-2. Technical Specifications ------------------------------------ (6)

1-3. Equipment Ratings ------------------------------------------- (9)

1-4. Supplied Accessories ---------------------------------------- (10)

2. INSTALLATION

2-1. Initial Inspection ----------------------------------------------- (10)

2-2. Connecting AC Power --------------------------------------- (10)

2-3. Cooling and Ventilation -------------------------------------- (10)

2-4. Position ----------------------------------------------------------

(10)

2-5. Warming-Up --------------------------------------------------- (11)

3. OPERATION

3-1. Controls, Indicators and Connectors --------------------- (11)

3-2. Operating Instructions---------------------------------------- (14)

3-3. Frequency Measurements ---------------------------------- (14)

3-4. Period Measurements --------------------------------------- (16)

3-5. Total Measurements ----------------------------------------- (16)

3-6. RPM Measurements ----------------------------------------- (16)

3-7. Use of RS-232C Serial Interfacing ------------------------

(17)

4. MAINTENANCE

4-1. Fuse Replacement ------------------------------------------- (18)

4-2. Adjustment and Calibration -------------------------------- (18)

4-3. Cleaning and Decontamination ----------------------------

(18)

5. OTHER

5-1. BNC Cable Considerations --------------------------------- (19)

5-2. Attenuator Probes -------------------------------------------- (20)

5-3. Line Frequency Measurements---------------------------- (20)

1. PRODUCT DESCRIPTION

5

1-1. Introduction

This reciprocal FREQUENCY COUNTER is a microprocessor-controlled

instrument for frequency measurement. Due to uniquely developed LSI circuitry in

an expanding/reciprocal system, high accuracy with 9-digit resolution is achieved

with a one second gate time. It covers a frequency range of from 0.1 Hz to 3.5

GHz based on a 10 MHz TCO (Temperature Controlled Oscillator). Other features

include:

l RPM (Revolutions Per Minute) Measuring Function

l External Frequency Standard Input with 9 Digit LED Display

l Attenuator

l Period

l Total

l Low Pass Filter

l Line Filter

Also provided is a self-test function for a quick check of several operating modes.

Each mode can be selected by a front panel push button switch with automatic

decimal points and indicators. The high accuracy, sensitivity and versatility of this

counter make it an extremely valuable instrument to the scientist, engineer,

experimenter and communications technician. Lightweight and compact size make it

practical for use by the hobbyist or field technician.

6

1-2. Technical Specifications

g INPUT A CHARACTERISTICS

h FREQUENCY RANGE: 0.1 Hz to 100 MHz (DC coupled)

30 Hz to 100 MHz (AC coupled)

h SENSITIVITY: 30 mV rms

h COUPLING: AC or DC selectable.

h IMPEDANCE: 1 MΩ resistance shunted by < 40 pF

h ATTENUATOR: x1 or x10 switch selectable

h LOW PASS FILTER: -3 dB point at approx. 100 KHz, switch selectable

h ACCURACY: ± Time base error ± resolution (Table 1)

h Resolution and Number of Displayed Digits

Time Base Selector INT EXT INT EXT INT EXT INT EXT

Gate Time 0.01S 0.1S 1S 10S

Number of Display

Digits

5 6 6 7 7 8 8 9

Frequency (Input A)

RESOLUTION

0.1 Hz-0.99 Hz 10 uHz 1 uHz 1 uHz 0.1 uHz 0.1 uHz 10nHz 10nHz 1nHz

1 Hz-9.9 Hz 0.1mHz

10 uHz 10 uHz 1 uHz 1 uHz 0.1 uHz 0.1 uHz 10nHz

10 Hz-99 Hz 1 mHZ 0.1mHz

0.1mHz

10 uHz 10 uHz 1 uHz 1 uHz 0.1 uHz

100 Hz-999 Hz 10mHz 1 mHz 1 mHz 0.1mHz 0.1mHz 10 uHz 10 uHz 1 uHz

1 KHz-9.9 KHz 0.1 Hz 10 mHz

10 mHz

1 mHz 1 mHz 0.1 Hz 0.1 mHz 10 uHz

10 KHz-99 KHz 1 Hz 0.1 Hz 0.1 Hz 10 mHz 10 mHz 1 mHz 1 mHZ 0.1mHz

100 KHz-999 KHz 10 Hz 1 Hz 1 Hz 0.1 Hz 0.1 Hz 10 mHz 10 mHz 1 mHZ

1 MHz-9.9 MHz 100 Hz 10 Hz 10 Hz 1 Hz Hz 0.1 Hz 0.1 Hz 10 mHz

10 MHz-99 MHz 1 KHz 100 Hz 100 Hz 10 Hz 10 Hz 1 Hz 1 Hz 0.1 Hz

100MHz 10 KHz

1 KHz 1 KHz 100 Hz 100 Hz 10 Hz 10 Hz 1 Hz

(Table 1)

7

h Max. Input Voltage Level

FIG. 1 MAX. Input Level. (Input A)

h PERIOD RANGE: 10 nS to 10 S

DISPLAY: n/u/m (nano/micro/milli) Sec. with decimal

point

h TOTAL RANGE: 10 Hz to 30 MHz

CAPACITY: 0 to 999 999 999, OVER FLOW : “OF”

h RPM RANGE: 600 to 600 x 106 RPM, OVER FLOW : “OF”

g INPUT C. CHARACTERISTICS

h FREQUENCY RANGE: 80 MHz to 3.5 GHz

h SENSITIVITY: 15mV from 80 MHz to 2000 MHz

20mV from 2000 MHz to 3.0 GHz

30mV from 3.0GHz to 3.2GHz

50mV from 3.2GHz to 3.5GHz

h COUPLING: AC only

h IMPEDANCE: 50 Ω ±5%

h MAX. INPUT LEVEL: 3 V rms sine wave

300

250

150

200

100

25

50

MAX INPUT VOLTAGE (ACV & DCV)

50100 500

FREQUENCY (Hz)

1K 1M 5M 10M 50M 100M

8

h Resolution and Number of Displayed Digits

Time Base Selector

INT EXT INT EXT INT EXT INT EXT

Gate Time 0.01S 0.1S 1S 10S

Number Of

Displayed Digits

5 6 6 7 7 8 8 9

Frequency (Input C)

RESOLUTION

100 MHz-999 MHz 10 KHz 1 KHz 1 KHz 100 Hz 100 Hz 10 Hz 10 Hz 1 Hz

1 GHz-3.7 GHz 100 KHz

10 KHz 10 KHz 1 KHz 1 KHz 100 Hz

100 Hz

10 Hz

(Table 2)

g TIME BASE CHARACTERISTICS

h TYPE: TCO (Temperature Controlled Oscillator)

h FREQUENCY: 10.000000 MHz

h STABILITY: ±1 PPM (±1 count)

h LINE VOLTAGE STABILITY:

Less than ± 1 PPM with ± 10% line voltage variation

h TEMPERATURE STABILITY:

±5 PPM from 0°C to 50°C

h MAX. AGING RATE: ±5 PPM/year

h INT. STD. OUT: 10 MHz (Internal Standard Frequency Output)

LEVEL: 1 V p-p or more. TTL (10TTL)

CAPACITANCE: 15pF

h EXT. STD. IN: 10 MHz (External Standard Frequency Input)

LEVEL: 1.5Vrms to 5Vrms

IMPEDANCE: Approx. 600Ω

g DISPLAY CHARACTERISTICS

h DISPLAY: Nine Digit 0.56" LED with M (Mega) or K (Kilo) Hz; nano, micro,

or milli (n/u/m) Sec.; GT (GATE TIME); H (HOLD); and OF

(OVERFLOW) indicators. FUNCTION and GATE TIME are

user selected. OF display is shown when the count exceeds 999

999 999.

h HOLD: In the FREQUENCY, PERIOD, TOTAL, RPM modes,

measurement in progress is stopped; and the last complete

measurement is displayed. When HOLD is released, a new

measurement begins.

9

h GATE TIME: Depending on input frequency

< 10 mS----------- Somewhere between 0.9 and 9mS

< 0.1 S------------- Somewhere between 9 and 90mS

< 1 S----------------Somewhere between 90 and 900mS

< 10 S---------------Somewhere between 0.9 and 9S

NOTE:

LAST MEASUREMENT DISPLAY WILL REMAIN FOR 10 SECONDS AFTER

SIGNAL OFF.

g DIMENSIONS AND WEIGHT

h Dimensions (WxHxD): 9.4 x 3.5 x 10.6” (240 x 90 x 270mm)

h Weigh (Approx)t: 5.5lbs. (2.5 kg.)

1-3. Equipment Ratings

l Power: 115VAC±10% , 50-60 Hz, 9 W

l Plug and Socket: 3 wire ac power plug and 3 wire outlet

l Fuse: 500 mA/ 250V F type

l Operating Environment:

TEMPERATURE: 0 °C to + 40 °C (Accuracy Specified at 23 °C ± 5 °C)

HUMIDITY: up to 85% RH (Relative Humidity) to 40°C without

temperature extremes causing condensation within the

instrument.

l Storage Environment:

TEMPERATURE: -20°C to +70°C

HUMIDITY: below 85% RH

l Insulation Category II: Portable equipment of local level.

l Pollution Degree: 2

l Protection to IEC 529: Ordinary

Note: Specifications are subject to change without notice.

10

1-4. Supplied Accessories

l User’s Manual --------------------------------------------------------------1

l BNC cable -------------------------------------------------------------------1

l Power cord-------------------------------------------------------------------1

l Spare Fuse-------------------------------------------------------------------1

2. INSTALLATION

2-1. Initial Inspection

This instrument was carefully inspected both mechanically and electrically before

shipment. It should be physically free of damage. To confirm this, the instrument

should be inspected for physical damage which may have occurred in transit. Also,

verify that all supplied accessories have been included.

2-2. Connecting AC Power

This instrument requires 115V AC, 50-60 Hz power through a 3-conductor AC

power cable to be plugged into a three-contact electrical outlet to secure grounding.

If adapted into a 2-conductor cable, use the ground terminal on the rear panel for

grounding the instrument.

CAUTION

THIS INSTRUMENT IS SET TO 115V, AC. BEFORE TURNING ON THE POWER

TO THE INSTRUMENT, MAKE SURE THE VOLTAGE OF THE POWER SOURCE

IS 115V, AC.

2-3. Cooling and Ventilation

No special cooling and ventilation is required. However, the instrument should be

operated where the ambient temperature is maintained.

2-4. Position

This instrument is built as a bench-type instrument with rubber feet and tilt stand

in place. The stand-up angle can be adjusted by changing the angle of the

carrying handle.

11

2-5. Warming-Up

Allow at least 30 minutes for the unit to warm up so that it can stabilize.

3. OPERATION

3-1. Controls, Indicators and Connectors

ON

POWER

OFF

k/u

SEC

RX

RMT

FREQ.

A

G.T

PRIOD

C

A

TOTAL

A

A

RPM

0

0

.

1

S

0.1S

1S

10S

m

H

TX

0.F

M/n

Hz

INPUT C

80MHz

3V MAX.

3.7GHz

100MHz

250V MAX.

INPUT A

1M

FUNCTION

19

18

15

16

10

12

9

2

3

1

4

5

6

14

8

GATE TIME

MULTIPLIER

HOLD

TOTAL RESET

OFF

LPF

INPUT A

COU

PLE

AC

ATT

1/1

ON

DC

1/10

20

50

FIG.2 FRONT PANEL

GATE INDICATOR: The gate light, when lit, indicates the main gate is open

and measurement is in progress.

RS-232C INDICATOR: TX (transmitting), RX (receiving) blinking

OVER FLOW INDICATOR: OF is displayed when there is an overflow.

DISPLAY: 9 digit (0.56“) green LED display used for all readings.

NOTE: LAST MEASUREMENT DISPLAY WILL REMAIN FOR 10 SECONDS

AFTER SIGNAL OFF.

12

UNIT INDICATOR: When lit, indicates that the frequency displayed is in

MHz, KHz, Hz and period is in nano, micro, or milli

(n/u/m) Sec.

HOLD INDICATOR: The HOLD function is engaged the when lit.

INPUT C: Use this input for all frequency measurements above 80

MHz. Female N type connector terminated in 50Ω.

LOW PASS FILTER: With this switch pushed in, the A input is routed through

a low-pass filter with a -3 dB point at approximately 100

KHz. When it is released, the A input is applied directly

to the counter.

ATT. SWITCH: When this switch is set to x10 (pushed in) the A input is

attenuated 10:1 before application to the counter. With

the switch set to x1 (pushed out), the A input signal is

applied unattenuated. The attenuator has no effect on

the C input.

COUPLE. SWITCH: This switch is used to select the input coupling mode,

AC or DC.

INPUT A: Use this input for frequency measurements below 100

MHz and all period measurements. Female BNC

connector. Input impedance is1 MΩ shunted by < 40 pF.

GATE TIME SWITCH: This switch selects the degree of resolution on the

display in all modes except TOTAL.

HOLD SWITCH: In the HOLD function, the display is held but the counter

continues to increment. When HOLD is released, the

display is updated and resumes counting.

FUNCTION SWITCH: This selects the desired operating mode.

a. FREQ. A: When this mode is selected, the counter reads the

frequency of the input at A. Resolution is selected

using the GATE TIME.

b. FREQ. C: When this mode is selected, the counter reads the

frequency of the input at C. All readings are in MHz.

c. PERIOD A: When this mode is selected, the counter reads the

period of the input at A. Resolution is selected using

13

the GATE TIME.

d. TOTAL A: When this mode is selected, the unit counts the cycles of

the signal at input A and continuously displays that count.

e. RPM A: When this mode is selected, the unit displays the RPM

(Revolutions Per Minute) of the signal at input A.

POWER SWITCH: This push type switch, turns on the power when pressed.

TILT STAND: Pull out to adjust tilt.

REPLACE ONLY WITH FUSE OF SAME RATING AND TYPE.

DO NOT REMOVE COVER. REFER SERVICING TO

DISCONNECT POWER SUPPLY BEFORE REPLACING FUSE.

1

INT STD OUT QUALIFIED PERSONNEL.

EXT STD IN

TO PREVENT ELECTRIC SHOCK HAZARD AND FIRE,

RS-232C

WARNING

6523

4

FUSE

230V~, 50Hz/60Hz

FIG.3 REAR PANEL

AC INLET: AC power input connector

INT/EXT TIME BASE SELECTOR:

Selects the source of the time base. EXT.STD. IN

sets up BNC as a nominal 600Ω input impedance

path for an external 10 MHz time base signal. INT. STD.

OUT sets up BNC to monitor the internal time base

signal.

GROUND TERMINAL

FUSE HOLDER: Replace fuse by unscrewing

INT/EXT TIME BASE BNC:

Provides a connector through which the internal time

14

base signal can be monitored or through which an

external time base signal can be applied (see item

above). The external signal should have a voltage

range of 1.5 V~5 V rms.

RS-232C CONNECTOR:

Connector for serial interfacing with a computer.

3-2. Operating Instructions

a. Connect the unit up to the AC power.

b. Turn on the unit by pushing in the POWER on-off switch.

c. Set the FUNCTION indicator position to FREQ A and the gate TIME

indicator to the 1 Sec, position.

CAUTION

1. APPLICATION OF INPUT VOLTAGES HIGHER THAN THE LIMITS LISTED IN

THE SPECIFICATIONS SECTION MAY DAMAGE THE COUNTER. BEFORE

APPLYING ANY SIGNAL TO THE INPUTS, MAKE CERTAIN THAT IT DOES NOT

EXCEED THESE SPECIFIED MAXIMUMS.

2. FREQUENCY COUNTER GROUND POINTS ARE CONNECTED DIRECTLY TO

EARTH GROUND. CONNECT GROUND OF THE CIRCUIT UNDER TEST TO

THE FREQUENCY COUNTER GROUND ONLY

3-3. Frequency Measurements

A. INPUT A (0.1 Hz to 100 MHz):

a. Apply the signal to be measured at input A.

b. Set the FUNCTION indicator to FREQ. A

c. Select the resolution using the GATE TIME selector switch.

d. The frequency is indicated on the display. The gate indicator is lit while

the measurement is in progress, and the display is updated at the end of

each measurement interval.

15

e. Engaging the HOLD switch “freezes” the display at the existing reading.

When HOLD is released, the display is updated and resumes counting.

f. Engage the ATTENUATOR if necessary. When set to x10 (pushed in),

the signal at input A is attenuated by a factor of approximately 10 before it

is applied to the counter. This helps prevent miscounting caused by noisy

or improperly terminated high amplitude signals.

g. Engage the LOW PASS FILTER (LPF) if necessary. When this switch is

pushed in, the signal at input A is routed through a low pass filter (-3 dB

point at approximately 100 KHz) before it is applied to the counter. This

helps eliminate counting errors in low frequency measurements by

minimizing effects of high frequency noise that may accompany the signal.

h. When making measurements near the lower cut-off frequency of input A

(10 Hz or less), use DC coupling (Push in the DC COUPLING switch).

B. INPUT C (80 MHz to 3.5 GHz)

CAUTION

THE MAXIMUM INPUT TO THIS INPUT IS 3 Vrms OVER THE INPUT

FREQUENCY RANGE. THE “X 10 ATTENUATOR” DOES NOT APPLY.

a. Apply the signal to be measured at input C.

b. Set the FUNCTION indicator to FREQ. C

c. Select the resolution using the GATE TIME selector switch.

d. The frequency is indicated on the display. The gate indicator is lit while the

measurement is in progress, and the display is updated at the end of each

measurement interval.

e. Engaging the HOLD switch “freezes” the display at the existing reading,

When HOLD is released, the display is updated and resumes counting.

f. The ATTENUATOR, LPF, and COUPLING switches have no effect with

input C.

16

3-4. Period Measurements

a. Apply the signal to be measured at input A.

b. Select the resolution using the GATE TIME selector switch.

c. The period is indicated on the display. The gate indicator is lit while the

measurement is in progress.

d. The ATTENUATOR, LPF, and COUPLING switches operate the same as

they do in the frequency measurements modes.

3-5. Total Measurements

The totalize mode is used to count the total number of events occurring during a

specific time period. The maximum frequency is 30 MHz.

a. With the FUNCTION switch, select the TOTAL A mode. Gate and unit

settings are ignored.

b. Apply the signal to be measured at input A. The accumulated counts will

be displayed continuously to a maximum count of 999999999. If this is

exceeded, the overflow message, OF, will be displayed.

c. The ATTENUATOR, LPF, and COUPLING switches operate the same as

they do in the frequency measurements modes.

NOTE

THE HOLD SWITCH MAY BE USED TO LATCH THE DISPLAY. THE COUNTER,

HOWEVER, WILL CONTINUE TO INCREMENT. WHEN THE HOLD SWITCH IS

RELEASED, THE UPDATED COUNT WILL BE DISPLAYED.

3-6. RPM (Revolutions Per Minute) Measurement

a. Apply the signal to be measured at input A. The count will be

displayed as revolutions per minute (RPM). Maximum count is 999999999.

If this is exceeded, the overflow message, OF, will be displayed.

b. The ATTENUATOR, LPF, and COUPLING switches operate the same as

they do in the frequency measurements modes.

17

3-7. Use of RS-232C Serial Interfacing

1) Hardware/Software Requirements

IBM PC/XT/AT or compatible computer

Microsoft Windows

Serial port for connection with counter

2) Output Data Formats

(1) Baud rate : 9600BPS

1 start bit (0)

8 data bit

1 stop bit (1)

NONE PARITY

(2) To Frequency counter

Command Parameter Terminate Code

'H' : HOLD '0' : OFF

'1' : ON

'2' : TOGGLE

CR (0DH)

'G' : GATE '0' : 0.01 SEC

'1' : 0.1 SEC

'2' : 1 SEC

'3' : 10 SEC

CR (0DH)

'D' : DATA REQUEST DON'T CARE CR(0DH)

'F' : FUNCTION SET N* CR(0DH)

'R' : REMOTE '0' : OFF

'1' : ON

CR(0DH)

N*= 0 1 2 3 4 5 6 7

3.5GHz,F/C FA NC FC PERIOD TOTAL RPM NC NC

(3) From Frequency counter

DATA UNIT

10BYTES include dp 4bytes CR

18

4. MAINTENANCE

CAUTION

FOR SAFETY, IT IS ESSENTIAL TO PROPERLY MAINTAIN AND SERVICE THIS

INSTRUMENT

WARNING

VOLTAGES WITHIN THIS INSTRUMENT ARE SUFFICIENTLY HIGH TO BE

LETHAL. COVERS MUST NOT BE REMOVED EXCEPT BY PERSONS

QUALIFIED AND AUTHORIZED TO DO SO, AND THESE PERSONS SHOULD

ALWAYS USE EXTREME CARE ONCE THE COVERS HAVE BEEN REMOVED.

4-1. Fuse Replacement

a. Disconnect and remove all connections from any live power source.

b. Unscrew the fuse holder with a screwdriver.

c. Remove the defective fuse.

d. Install a new fuse of the SAME SIZE AND RATING.

e. Screw the fuse holder back in.

CAUTION

REPLACEMENT FUSES MUST HAVE THE SAME SIZE AND RATING AS THOSE

BEING REPLACED.

4-2. Adjustment and Calibration

Regular adjustment and calibration of this instrument is recommended. The

procedures involved should be executed by qualified and authorized personnel only.

4-3. Cleaning and decontamination

The instrument can be cleaned with a soft clean cloth to remove any oil, grease

or grime. Never use liquid solvents or detergents. If the instrument gets wet for any

reason, dry it using low-pressure clean air at less than 25 PSI. Use care and caution

19

around the window cover areas where water could leak into the instrument while

drying.

5. OTHER

5-1. BNC Cable Considerations

The accuracy of radio frequency measurements can be affected by the

connections between the signal source and counter. The main issues involved are

standing waves and cable shunt capacitance.

Waves propagating along a transmission line will be reflected at its ends if the

line is not terminated in its characteristic impedance. These reflections will set up

standing waves in the line, which may cause damage to the signal source or

produce inaccurate measurements. This effect increases as the cable length

reaches one-fourth of the wavelength for the frequency being measured. Standing

waves can be minimized by keeping cable lengths short, or eliminated by providing

a proper termination. RG58 cable, for example, has a characteristic impedance of

50Ω. The proper termination for this cable would, therefore, be a 50Ω resistor

between the center conductor and the shield. A standard BNC, 50Ω cable

termination is most often used for this.

Input A has an input impedance of 1 MO shunted by < 40 pF. Radio frequency

measurements made at this input will experience standing waves and attenuation

due to the shunt capacitance of the cable which adds to the shunt capacitance at

the input. For RF measurements at input A, it is recommended that a 50Ω

termination be used, or that the cable be no longer than three feet (91 cm).

Input C has a built in impedance of 50Ω, thus the need for an external

termination is eliminated.

In situations where a 50Ω termination could affect bias voltages or other DC

voltages in the circuit under test, a blocking capacitor should be used.

20

5-2. Attenuator Probes

When measuring signals at input A that will exceed its maximum input voltage

level (See FIG. 1), a 10:1 attenuating probe such as an oscilloscope probe should

be used.

NOTE

DO NOT USE A 10:1 PROBE WITH THE INPUT C. THESE PROBES ARE

DESIGNED WITH A 10:1 ATTENUATION FOR AN INSTRUMENT WITH AN

INPUT RESISTANCE OF 1 M Ω. THE 50 Ω TERMINATION OF INPUT C WOULD

RESULT IN UNACCEPTABLY HIGH ATTENUATION.

5-3. Line Frequency Measurements

When making line frequency measurements, use of the LOW PASS FILTER, the

ATTENUATOR, and/or the 10:1 probe is recommended.

WARNING

USE CAUTION WHEN MEASURING THE LINE FREQUENCY OF AN AC

OUTLET. USE THE PROBE TIP ONLY, AND MEASURE BOTH SIDES OF THE

LINE. THE NEUTRAL SIDE WILL GIVE A ZERO READING AND THE HOT SIDE

WILL PROVIDE THE DESIRED MEASUREMENT. DO NOT USE THE "GROUND"

LEAD OF THE PROBE. REMEMBER THAT THE CHASSIS OF THE COUNTER

AND THE “GROUND” LEAD OF THE PROBE ARE ALREADY AT EARTH

GROUND (VIA THE 3-WIRE POWER CORD OF THE INSTRUMENT). TOUCHING

THE “GROUND" LEAD TO THE 'HOT" SIDE OF THE LINE WOULD PLACE A

DIRECT SHORT ON THE POWER LINE THROUGH THE PROBE CABLE,

RESULTING IN A BIG SPARK, DAMAGE TO THE PROBE CABLE, AND

POSSIBLE INJURY TO THE USER.

21

Limited One-Year Warranty

B&K Precision Corp. warrants to the original purchaser that its product and the

component parts thereof, will be free from defects in workmanship and materials for

a period of one year from the data of purchase.

B&K Precision Corp. will, without charge, repair or replace, at its’ option, defective

product or component parts. Returned product must be accompanied by proof of

the purchase date in the form a sales receipt.

To obtain warranty coverage in the U.S.A., this product must be registered by

completing and mailing the enclosed warranty card to B&K Precision Corp., 22820

Savi Ranch Parkway, Yorba Linda, CA 92887 within fifteen (15) days from proof of

purchase.

Exclusions: This warranty does not apply in the event of misuse or abuse of the

product or as a result of unauthorized alternations or repairs. It is void if the serial

number is alternated, defaced or removed.

B&K Precision Corp. shall not be liable for any consequential damages, including

without limitation damages resulting from loss of use. Some states do not allow

limitation of incidental or consequential damages, so the above limitation or

exclusion may not apply to you.

This warranty gives you specific rights and you may have other rights, which vary

from state-to-state.

Model Number: ______________ Date Purchased: __________

22

Service Information

Warranty Service: Please return the product in the original packaging with proof of

purchase to the below address. Clearly state in writing the performance problem

and return any leads, connectors and accessories that you are using with the device.

Non-Warranty Service: Return the product in the original packaging to the below

address. Clearly state in writing the performance problem and return any leads,

connectors and accessories that you are using with the device. Customers not on

open account must include payment in the form of a money order or credit card. For

the most current repair charges contact the factory before shipping the product.

Return all merchandise to B&K Precision Corp. with pre-paid shipping. The flat-

rate repair charge includes return shipping to locations in North America. For

overnight shipments and non-North America shipping fees contact B&K Precision

Corp..

B&K Precision Corp.

22820 Savi Ranch Parkway

Yorba Linda, CA 92887

Phone: 714- 921-9095

Facsimile: 714-921-6422

Email: service@bkprecision.com

Include with the instrument your complete return shipping address, contact name,

phone number and description of problem.

23

22820 Savi Ranch Parkway

Yorba Linda, CA 92887

USA

TEL: 714-921-9095

FAX: 714

-

921

-

6422

PN: 481-532-9-001

Printed in Korea