nistUNITED STATES

DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS

AND TECHNOLOGY

NATL INST OF STAND SJEjHJUfi

A 11 10 3 a<1fll35

NIST

PUBLICATIONS

NIST Technical Note 1345

.

Power Measurement System

for 1 mW at 1 GHz

Fred R. Clague

Electromagnetic Fields Division

Center for Electronics and Electrical Engineering

National Engineering Laboratory

National Institute of Standards and Technology

Boulder, Colorado 80303-3328

\

U.S. DEPARTMENT OF COMMERCE, Robert A. Mosbacher, Secretary

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY, John W. Lyons, Director

Issued November 1990
National Institute of Standards and Technology Technical Note 1345

Natl. Inst. Stand. Technol., Tech. Note 1345, 32 pages (November 1990)

CODEN:NTNOEF

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1990

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402-9325
CONTENTS

Page

ABSTRACT v

1. INTRODUCTION 1

2. OPERATION 2

2.1 Initial Steps 2

2.2 Measurement 2

3. SYSTEM DESCRIPTION 6

3.1 Theory of Operation 6

3.2 Hardware 8

3.3 Software 8

4. ERROR ANALYSIS 9

4.1 Systematic Error Components 9

4.1.1 Voltmeter Uncertainty 9

4.1.2 Uncertainty in Thermistor Mount Effective Efficiency 11

4.1.3 Mismatch Uncertainty 11

4.1.4 Dual Element Error 12

4.2 Random Error 14

5. REFERENCES 15

APPENDIX A Instrument Specifications 16

APPENDIX B Software Listing 17

in

ABSTRACT

An automated measurement system designed to measure power accurately at the level

of 1 mW and at the frequency of 1 GHz is described. The system consists of

commercial IEEE Std-488 bus-controlled instruments, a computer controller, and

software. The results of a series of measurements are output to the computer display

and, optionally, to a printer. The results are the mean of the measurement series and

an estimate of the systematic and random uncertainty. The total estimated uncertainty

for the average of six consecutive measurements of a nominal 1 mW, 1 GHz source is

typically less than 1 percent. The system can measure any power from 0.1 to 10 mW

at any microwave frequency by making appropriate changes to the software and

possibly, the hardware.

Key words: automated measurement; microwave; microwave power measurement;

power; power measurement; power measurement system.

POWER MEASUREMENT SYSTEM FOR 1 mW at 1 GHz

Fred R. Clague

National Institute of Standards and Technology

Boulder, Colorado 80303

1. INTRODUCTION

This system is especially designed to accurately measure microwave power at the level of 1 mW and

the frequency of 1 GHz. Specifically, it supports the calibration of the Wavetek 8502A 1 pulse power

meter, which has a 1 mW, 1 GHz calibrator output port. The manufacturer's specification on the

power level of that output is ±1.5 percent. Use of the system is not restricted to this specific

application; relatively simple modifications to the software would make it possible to measure other

power levels and frequencies.

The microwave power measurement method is based on the dc substitution technique. The system is implemented using a commercial version of the NIST-developed Type IV microwave power meter, a commercial coaxial thermistor mount, a digital voltmeter, and a dedicated computer controller. The

Type IV power meter is not direct reading; the substituted dc power is calculated using readings

obtained from the digital voltmeter. The computer controls the measurement process, calculates the

results, and prints them out. The measurement results include an estimate of uncertainty for each data

set. The automation also allows the implementation of a procedure that adequately corrects for

thermistor mount drift caused by external temperature changes. The system is packaged in a combination operating/shipping case.

1 Certain commercial instruments and software products are identified in this document in order

to adequately specify the instrument supported and the measurement system. Such identification does

not imply recommendation or endorsement by NIST nor does it imply that the identified items are

necessarily the best available for the purpose.
2. OPERATION

2.1 Initial Steps

Before turning on the Type IV power meter be certain that the thermistor mount is connected to it. The output of the Wavetek 8502A calibrator is found to be more stable after a 2 hour warmup, rather

than the 30 minutes specified by the manual. If possible, the 2 hour warmup period is recommended

for both the 8502A and the power measurement system. It is also recommended that the thermistor

mount be attached to the calibrator output for at least 30 minutes before making the measurement.

This will minimize the temperature drift of the mount, improving the measurement accuracy.

Before turning on the computer, load the disk marked "System and Program" in the drive, then turn on the power. The operating system will be automatically loaded. The computer screen will display

the time and the several soft-key options: SET CLOCK, LOAD PROGRAM, and EXIT. (The soft

keys, or function keys, are the set of eight dark grey keys along the top of the keyboard labeled Fl

through F8.) Set the time if needed, and then press the LOAD PROGRAM soft key. The

measurement program will be loaded and run.

2.2 Measurement

The first screen displayed by the

program is shown in figure 2.1. To

see instructions on how to operate

the 8502A (to turn the calibrator

output on and off), press Fl. To

enter the serial number of the 8502A

being measured, press F2; the serial

number will then be printed with the

measurement result. To change the

number of repeated measurements

to be averaged in a set (at least 6 to

10 is recommended), press F3. To

begin the measurement set, press F4.

To exit the program, press F5.

- - - MEASUREMENT MENU - - -. H KAVETEK OPERATING INSTRUCTIONS : i» INPUT HAVETEK SERIAL NUMBER

(No S/N in memory)

jgg CHANGE # OF MEASUREMENT POINTS '. (Present setting - 8 ) ££ BEGIN MEASUREMENT IB EXIT PROGRAM

User 1 Caps Command HIHHBI Hil JE *

Figure 2.1. Screen display of the measurement menu.
Figure 2.2 shows the screen that

appears when the first item is select- ed from the Measurement Menu. It

gives brief instructions for manually

controlling the 8502A calibrator

output based on information given in

the instrument's operating manual.

The four numbered steps shown on

the screen should be carried out

before proceeding with the measurement.

CONTROLLING 8502ft CALIBRATOR OUTPUT

Press the following 8502A front panel control keys in the sequence indicated:

(i)-'CH', (2)-'Nenu\ (3)-'F3\ (4)-'Fi\

Then, pressing the 8502ft key '7' will turn the calibrator

'

output ON, and pressing the 8502ft key 'CLEAR' will turn the calibrator output OFF

For store detail see 'Calibrator Output Level Teat' on page 6-2

of the 8502A manual.

CAUTION; Oo not press any UNITS key when the nount is connected to the calibrator. This will cause the calibrator to output 100 tM which might damage the nount.

User 1 Coanand

Figure 2.2. Screen display of operating instructions for the

calibrator output.

P M R M T R I

'MOUNT: -HP 84788, S/M 21068.20034 17:64:20 16 Aug 1998 POWER METER: KflVETEK MODEL 8562ft, S/ff 1813641

NO. POWER PWR- l.OmW VI Delta V Vj Drift, fief. Offset («) W '(VOLT) W) (uV/») (»V)

Figure 2.3 shows the screen that appears when F4 is pressed to start the measurement. Just before the

message TURN RF ON (PRESS

8502A KEY '7') is displayed, the

computer will beep once. At that

point press key 7 on the 8502A to

turn the rf on and wait for a pair of

beeps from the computer. The message will change to TURN RF OFF

(PRESS 8502A 'CLEAR'). After

pressing the CLEAR key, wait until

a single beep sounds again, before

pressing key 7 to begin the next measurement in the set. This se- quence will be automatically repeated until all the measurements making up the set have been made.

Figure 2.3. Screen display while the measurement is made.
When the desired number of measurements is complete, the final screen that is displayed is shown in

figure 2.4.

P H R _M T R 1

: MOUNT: HP 8478B, POWER HETER: WAVE

NO. POWER

... <««):

: ,.i: 1.004607

.

. 2 1.005146 3 1.005618

.4 1.095635

5 1.005678:

6 1.005731

M

S/N 2106fi20054 TEK MODEL 8502A, PWR- l.OtuW W

E fl S U R E M EN T

S/N 1813641

. Vi . Dei (a V

(VOLT). (bV) 2.296970 43.701 2.296942 43.726. 2.296909 43.747

2.296878 43.748 2.296842 43.751 2.296884 43,754

COMPLETE

16;59:46 16

VI art ft Ref (uV/s)

Bug 1990

. Offset

(aV) •00.461

<-00.515

4-00.562.

:

«30.564 MM. 568

t00. 573

-2,1

-2.1: -2.2

-2.5

-2.7

-3.1

-7.348 : -7.348

-7.347

-7.347

-7.345

-7,345

RESULTS:

ftVG ft*-. (nw) 1.005403

(NO- l.OmM

it)

00. 540 Ml

MAX DEV '" ST DEV SVS UNC m '

. m

,044 6.843

Uaer 1 Caps HI

TOTUNC W

0,897

CoBBdnd

HD. 033, -0.079

Figure 2.4. Screen display of the measurement results.

The upper part of the display summarizes each measurement in the set as explained in table 2.1 below.

Table 2.1. Explanation of the upper part of the measurement screen

Column Heading Explanation

NO. Number of the power measurement.

POWER Result of the power measurement in milliwatts.

PWR - 1 mW Percent deviation of the measured power from 1 milliwatt.

VI Power meter voltage with the rf off (see section 3.1).

Delta V Change that occurs in the power meter voltage when the rf is turned on.

VI Drift Drift of V\ in /uV/s that occurred from the beginning of the measurement

until it was complete. Note that if the drift is greater than 10 j/V/s the

measurement should be repeated after waiting a period of time for the

mount temperature to further stabilize.

Ref. Offset The compensation element channel is used as the voltage reference; this column shows the voltage difference between the measurement thermistor

channel and the compensation thermistor channel when the rf is off.
The final results are displayed on the screen below the horizontal dashed line. The explanation of each

column is given in the following table.

Table 2.2. Explanation of the results section of the measurement screen

Column Heading Explanation

AVG PWR Average power in milliwatts computed from the measured data set. AVG - lmW Percent deviation of the average power level from 1 milliwatt.

MAX DEV The maximum positive and negative deviations from 1 milliwatt.

STD DEV The standard deviation of the individual measurements.

SYS UNC The total calculated systematic uncertainty in the measurement.

TOT UNC Total uncertainty; the systematic uncertainty plus three times the standard

deviation of the mean.
3. SYSTEM DESCRIPTION

3.1 Theory of Operation

The NIST Type IV power meter is not a direct reading instrument. An external precision dc voltmeter

must be connected to the power meter, and the power is calculated from the voltmeter readings. The

power, P, is given by

where V x is the output voltage without rf power, V2 is the voltage with rf power, and R is the

operating resistance of the mount. Note that the so-called "bolometric power" is simply the change of

the mount dc bias power as rf power is applied and removed.

It can be seen from eq (3.1) above that, as the rf power becomes small, V2 approaches Vx. Because

of the uncertainty "magnification" that occurs in the computed difference of two nearly equal numbers,

the power measurement uncertainty becomes very large as the power decreases. The solution to this problem is to measure the difference between V\ and V2 directly. This requires a reference voltage

generator (RVG) which is set nominally equal to Vx and, in effect, stores Vx

.

When an RVG is used, the expression for calculating power from measured voltages becomes,

P= — (2Vi - AF)AF, (3.2)

where R and V x were previously defined, and AV is the change in the power meter voltage when rf

is applied. In providing for a first-order correction of mount drift, the value of V\ and AV are

estimated by assuming linear drift and measuring several other voltages while the rf is off, as shown

in figure 3.1.
The diagram in figure 3.1

depicts the outputs of the

power meter and RVG as a

function of time while the rf

is cycled on and off. The

measurement sequence of

five voltage and time readings used to calculate the

power and correct for the

mount drift is also shown.

Note that the reference voltage generator is not set

equal to Vu nor is it constant with time. This is because it is convenient to use the compensation ele- ment of the mount, biased by

the second power meter channel, as the reference voltage generator. Thus the RVG does drift during

the measurement, but this change is also corrected, to first order, by the measurement series.

In terms of the measured voltages, the values to be used in eq (3.2) are given by,

RF OFF

RF OFF nT^T^

f 11

Vim RF ON Vixf Vw

Vtype n — " i V2X

1 2

t f<

Vrvg

s aS

tl t5

Figure 3.1. Measured power meter voltages vs time.

Vx = Vu + H-h

u-h,

(vv -vu ) (3.3)

and,

W ' vu - ViXi + h~h

\h-h,

VlXf MXi)

(3.4)
3.2 Hardware

The system block diagram is shown in figure 3.2. The

input switching to the digital

voltmeter (DVM) is done

with the multiplexer internal

to the DVM. The dual power meter also has an IEEE

Std-488 bus interface with

controlled output switching,

but it is not used in this

application. The specifications for the instruments are

given in appendix A.

DVM NITH MULTIPLEXER CONTROLLER

IM=UT .n=f

----<:

v-\ \-\ \~\

+ - OUTPUT

(CCtPENSRTION

ELEfCNT) fj|jS

GPIB

+ * *-

OUTPUT

(^CRSURE^CNT

ELEhtNT) I^JJS

DURL TYPE IV POWER METER

THERMISTOR MOUNT

Figure 3.2. System block diagram.

3.3 Software

A software listing is included as appendix B. Comments at the beginning of the code define the

variables (and their location) that one might want to change for other applications such as a different

power level or a new mount calibration factor.
4. ERROR ANALYSIS

4.1 Systematic Error Components

The factors contributing to the total systematic uncertainty are:

1. Uncertainty in the dc voltage measurements.

2. Uncertainty in the thermistor mount effective efficiency calibration.

3. Mismatch uncertainty due to the source (8502A calibrator output) reflection coefficient

and the thermistor mount reflection coefficient.

4. The "dual element substitution error" associated with the coaxial thermistor mount.

5. Type IV power meter uncertainty. There are four sources of possible error internal to the

power meter. They are, the reference resistors, the operational amplifier open loop

gain, input offset voltage, and input bias current. The Type IV error analysis [1] indicates

that all of them are negligible compared to the four factors listed above.

The first four of these items will be considered individually in the following sections.

4.1.1 Voltmeter Uncertainty

The effect of uncertainty in the individual voltmeter readings can be determined by taking the total

differential of the expression for power, eq (3.2),

dP - — [AFdJ^ + (K, - AV) dAK], (4.1)

where, in terms of the measured parameters,

dF1= (l *Tlf )6Vu

* Tlf 6Vlf , (4-2)

dAK = bVtx

+ ( 1 + T2f ) 6V1Xi * T

2f bVlxf , (43)

T = h

ll (4.4)

lf

t - t

'
and,

T = u - u U ~h

(4.5)

The quantities 6VU, 6Vlf , dVlXh &V\xf, and &ViX, are the uncertainties in the measured values of Vu, V\p V\xi> V\xp and V1X . These uncertainties in the measured voltages are based on the voltmeter

specifications, which are usually given in two parts as a fraction of reading term, a, and a fraction of

full scale term, B. The general expression for the voltmeter uncertainty is given by,

8K-«Kreading " fullscalt (4.6)

Figure 4.1 shows the uncertainty in power measurement as a function of power level near 1 mW, as

calculated using the above procedure (in the calculations, the sign of the independent terms are chosen

to give the maximum contribution to the total uncertainty) for the voltmeter, power meter, and

measurement configuration used in this system.

0.10

0.09 TOTRL. UNCERTBINtY UtTH RVG .

0.08 ±|::i::l::i:p: : f?a» 2BB ohms ; VI :: : ; 2.368 volts ' DCOccCO

uu

0.07

0.06

=H \ ::|::p:

; RVG: 2 .;i2j93;:;!ybK;t;s;;;|

1—zLXJ occ

1X1 Q_

0.05

0.04

0.03

0.02

0.01

E~ ..:.' '!..'"''

': '^^^^ ' ';. :

; :. !.'••;•

c H i i i I i i i I I i i i i i | j j..|..j | | | | j..| ,j .j | .j..j..j..j..|..j..j..j..j..| | j. j..j

| j.j

i i

) 0.2 0.4 6 0.8 1.0 1.2 1.4 1.6 1.8 2

POWER, MILLIWATTS

Figure 4.1. Power measurement uncertainty from the DVM.

10
4.1.2 Uncertainty in Thermistor Mount Effective Efficiency

This is the uncertainty of the NIST thermistor mount calibration. The NIST calibration also gives a

value for the mount calibration factor Cf

, which is the factor used in this measurement rather than

effective efficiency alone, and is defined later in this section. The values listed on the report of

calibration will, of course, be constant for any given mount, until the unit is recalibrated.

The thermistor mount should be recalibrated periodically.

4.1.3 Mismatch Uncertainty

The net power delivered to a termination by a source is given by,

i - ir I 2

|i -r,r,|2

where P is the power the source would deliver to a nonreflecting termination, Tg is the generator

reflection coefficient, and r, is the termination reflection coefficient. Ideally, the calibrator should

deliver a net power of 1 mW to the power detector being calibrated, but that can only be accomplished

if the complex reflection coefficients of the power detector, generator, and calibrating thermistor

mount are known, which is generally not the case. Assuming, then, that the calibrator output

specification is the power delivered to a nonreflecting load, P , the measured output is given by,

*m I 1 -^ |2 p =-»! £_=« (4.8)

o i- i - K\

where Pm is the bolometrically measured power, r\ m is the effective efficiency of the thermistor mount,

Fg is the generator reflection coefficient, and Tm is the thermistor mount reflection coefficient. The

denominator of eq (4.8) is the mount calibration factor,

c,- 11.(1- irj2 ),

< 4 - 9)

n
so that eq (4.8) becomes,

The value of Tm has been measured during the NIST calibration, but only an upper limit to the

magnitude of Tg is known (from the source return loss specification). Thus, only the limits to the term

involving the reflection coefficients are known,

i - irjirj)2 * |i -rg rj^ { i + |rt ||rj)*, (4.n)

so that P is also only known within the limits,

"(i - |rj|rj) 2 ^p ^(i irjirj) 2

. (4.12)

This uncertainty in P is the mismatch uncertainty and its relative value is given to first order by,

±2|r

f ||rj. (4.i3)

The return loss specification on the calibrator output is greater than 25 dB, which results in a value

for IrJ of < 0.056. The value of lr m I for the thermistor mount provided is 0.019; together these

give a mismatch uncertainty in P of ±0.21 percent.

4.1.4 Dual Element Error

The power detector is a dual-element coaxial thermistor mount. Dual-element bolometer units are

nonlinear with power level as a result of a dc-rf substitution error that arises because the two elements

are not identical [2j. The error is of concern in this measurement because it is being made at 1 mW,

12
while the NIST calibration of mount efficiency is done at 10 mW. The only way to determine the error magnitude is by direct measurement.

In this case, the method used was to connect the coax mount to one arm of a nominally equal power

splitter (for this measurement, a waveguide "magic tee" in WR'90), and a single-element waveguide

mount to the other arm. The ratio of the two bolometric powers was determined at 10 mW and again

at a randomly selected level between 10 mW and 0.1 mW. The change in the ratios as determined at

the two power levels was a measure of the dual-element error.

Figure 4.2 shows results for two identical model waveguide mounts at 9.1 GHz. The increased spread

of the data as the power level decreases is typical of bolometric measurements because of the small

change in dc power that occurs at low microwave power levels. The -10 dB point on the plot is approximately equal to 1 mW.

O

i

HIO

z

<

X

o

UJOoc

UJ

Q0.10

0.05

0.00

0.06

-0.10

J ._—.**- rf r WS. -".!!»•!: •->j»! P. ,*•-_> •>' " \\ *

« • a *

| "" ."" ' '\'' : ~-~

•'

}

t • "

> •

. ARM#1: WAVEGUIDE MOUNT

• ••

" ARM #2: WAVEGUIDE MOUNT

1 .._.—I—.—.

-10

dB CHANGE IN POWER

-15 -20

Figure 4.2. Change in the power ratio of 2 waveguide mounts vs power level.

13
Figure 4.3 is the result for a coax mount compared with one of the waveguide mounts. The change in

ratio at the 1 mW level (-10 dB point) is about 0.035 percent. This is the uncertainty that can be

expected in the effective efficiency and thus the power measurement at 1 mW, given the calibration

is done at 10 mW.

LUoZ

<

o

LUo

ccLU

0.

0.10 i—i 1—i—i0.05 -

0.00

-0.05 -

-0.10

i

i i i i i

,^-^;^^H,^:,

.•'

ARM#1: COAX MOUNT

ARM #2: WAVEGUIDE MOUNT

-5 -10

dB CHANGE IN POWER

-15 -20

Figure 4.3. Change in the power ratio of a coax mount to a waveguide mount vs power level.

4.2 Random Error

In section 2.2, figure 2.4 shows the measurement screen. The last three columns under the Results

section show the standard deviation, the systematic uncertainty, and the total uncertainty of that

measurement set. The random contribution to the total uncertainty is chosen to be three times the

standard deviation of the mean.

14
5. REFERENCES

[1] Larsen, N.T. A new self -balancing dc-substitution rf power meter. IEEE Trans. Instrum.

Meas. IM-25: 343-347; 1976 December.

[2] Engen, G.F. A dc-rf substitution error in dual-element bolometer mounts. IEEE Trans.

Instrum. Meas. IM-13: 58-64; 1964 June-Sept.

15
APPENDIX A

Instrument Specifications

1. Digital voltmeter: 6V2 digit resolution; 3 volt dc range with 0.0025% of reading and 0.0002%

of full scale accuracy; 300 mV dc range with 0.0035% of reading and 0.0013% of full scale

accuracy; IEEE Std-488 bus; optional integrated reed relay multiplexer.

Note: meters with other dc ranges such as 100 mV, 1 volt, and 10 volts are also usable.

For instance, a 6V2 digit meter with 0.00034% of reading and 0.002% of full scale

accuracy on the 100 mV range, 0.00024% of reading and 0.00033% of full scale

accuracy on the 1 volt range, and 0.00023% of reading and 0.00016% of full scale

accuracy on the 10 volt range, gives results comparable to the 3 volt-300 mV meter.

2. Multiplexer: integrated with the DVM (or separate unit); minimum 6 single-pole, single-throw

contacts; maximum thermal offset of 3/^V; IEEE Std-488 bus.

3. Dual NIST Type IV power meter (or two single units).

4. Coaxial thermistor mount: type N male connector; temperature compensation

thermistors; dc bias power « 30mW; maximum \r\ < 0.025; NIST calibration at 1 GHz.

5. Computer controller: programmable in Hewlett Packard Work Station Basic version 5.13

("Rocky Mountain Basic"), or TransEra "HT Basic" with IEEE Std-488 capability; IEEE Std488 bus.

16
APPENDIX B

Software Listing

100 105

110

115 120

125

130

135 140

145

150

155

160

165

170

175

180

185 190 195

200

205

210

215

220

225

230

235

240

245

250

255 260

265 270

275

280

285

290

295

300

305 310

315 320

325

330 335

340

345

350

355

360

365

370 375

380

385 390

395 400

405 410

415

420

425

430 435

440 445

450

455

460

465 470

475

480

485 490

File$="PWRMl"

Rev$="9011210805" I FRC

I Started:9001111632/FRC

I NTL author of the subprograms

I Errors, Select_v, and Hp_3457

This program application is the measurement of the 1 mW

calibrator output of the Wavetek 8501A peak power meter.

NOTES:

This version measures VI and delta V with the compensation element used as an RVG. It also calculates the measurement uncertainty.

Total measurement uncertainty includes:

Mount calibration factor uncertainty of 0.5973% (For #20054 with Cal Factor of 0.9897) and calculated mismatch uncertainty for the source (

| Gamma |<=0. 056) and the mount (|Gamma|<=0.019) of 0.21%. The total is 0.8073% plus the 0VM and Type IV contribution.

INSTRUMENTS CONTROLLED:

1. HP3457A 0VM

2. HP2225A PRINTER

ADDRESS

722

701

DESCRIPTION OF THE MAIN INITIAL VALUE VARIABLES:

The following are in the labeled common named "/Dvrn/":

** "Dvm_name$" - the DVM identifier (ie, HP3457A)

* "PO" - power level in milliwatts. The measurement results are compared with this value. Default setting is 1 mW.

* "R0° - mount operating resistance in ohms. Normally 200 ohms for a coax mount and may be either 100 or 200 ohms for

a waveguide mount. Default setting is 200 ohms.

The following are in the labeled common named "/Mount/":

"Mount$" bolometer mount identifier (manufacturer,

model, and serial number).

* "Cf" - NIST measured mount calibration factor. Oefault setting

is 0.9897 for the supplied mount. Value must be changed

after mount replacement or recalibration.

The following are in the labeled common named "/Errs/":

* "Cfu" - total quoted uncertainty of the NIST measured mount

calibration factor. Default setting is 0.5973% for the supplied mount.

* "Mmu" - calculated mismatch uncertainty. Oefault setting is 0.21% as indicated in the notes above.

The following is in the labeled common named "/Wavetek/":

"Sn$" - records the serial number of the Wavetek meter

being measured. It can be input before the measurement from an item on the initial menu.

CHANGING INITIAL VALUE OF VARIABLES

These variables are initally defined in the subprogram "Set_up"

To change them, move to the subprogram by executing, "EDIT S". Change the values as needed and "Re-store" the program if the changes are to be permanent.

t ** iThis variable is initally defined in the subprogram "Hp_3457".

I | If a different DVM is used, along with the name, the percent

17
495

500

505 510

515 520

525

530

535 540

545

550

555

560

565

570 575

580 585

590

595

600

605 610

615 620

625

630

635

640 645

650

655 660

665 670

675 qui 680

685

690

695 I 700 I 705 H 710

715

720

725 730

735

740

745

750

755

760

765

770

775

780 785

790 795 BOO

805

810

815 820

825

830

835

840

B45 850

855

860

B65 870

875 880

B85

of reading and the percent of full scale specifications must

also be changed in that subprogram. Execute "E0IT hp3457" to move to the subprogram. *********** * * MAIN PROGRAM ***************

OPTION BASE 1 COM /Dm/ P0,R0,A1 / A2,A3 / A4,A5,B1,B2,B3,B4,B5,R1,R2,R3,R4,R5

COM /Dm/ Dvm_name$[40] I0VM ID COM /Errs/ Dp,Vlc,Vli ,Vlf,Vlxi ,Vlxf,Vlx,V2x,Tlfac,T2fac / Cfu,Mmu

COM /Mount/ Mount$[40],Cf [Mount ID COM /Wavetek/ Sn$[7] I For the serial number

REAL P(100,l) IFor the power measurements

CONTROL 2,1;0 [Turn PRT ALL off

KEY LABELS OFF I Turn off key labels

CALL Set_up

CALL Hp_3457

CALL Init Nt=6

LOOP

CALL Menul(Nt,Quit)

IF Quit THEN Quit

CALL Hdr REDIM P(Nt,l)

FOR N=l TO Nt DISP N CALL Meas(N,Pl)

P(N,1)=P1

WAIT 1 NEXT N CALL Stats(P(*))

OUTPUT 722; "TRIG AUTO" PRINT TABXV(30,1),CHR$(128)

CALL Menu2

ENO LOOP

t:CLEAR SCREEN

END

I

IFor mount & measurement parameters

I Get DVM parameters

I Hardware initialization

[Default No. of meas

I To repeat measurement sets

[Terminate

[Screen header [Redimension

[Measurement loop

[Do the measurement

[Fill array for statistics

[Wait before measuring again

[Calculate the statistics of the run

[Let DVM continue reading

;CHR$(136);" MEASUREMENT COMPLE

[Post measurement soft keys

[Terminate program

T E

********* * * SUB PROGRAMS *** **********

SUB Meas(N,Pl)

OPTION BASE 1 Sys_prty=VAL(SYSTEM$("SYSTEM PRIORITY")) [Determine system priotity

Lcl_prty=Sys_prty+l I Set local priority 1 higher for ON KEY

ON KEY LABEL " ",Lcl_prty GOTO 8ail_out

ICOM /Dm/ P0,R0,A1,A2,A3,A4,A5,B1,B2,B3,B4,B5,R1,R2,R3,R4,R5

COM /Dm/ 0vm_name$[40] I DVM ID COM /Errs/ Dp, Vlc.Vli ,Vlf,Vlxi ,Vlxf,Vlx,V2x,Tlfac,T2fac / Cfu,Mmu

COM /Mount/ Mount$[40],Cf [Mount ID

ICALL Ovm(Vli,Tli) I VI before rf turn_on OUTPUT 722; "CHAN 0" [Connect for delta V WAIT .2 I CALL Dvm(Vlxi,Tlxi) [Initial delta VI (Vlxi ) with rf off Vt=Vlxi+Vli-SQR(Vli"2-9.E-4*R0)ICalculate threshold for Rf sub CALL Rf(l,Vt) WAIT 1 CALL 0vm(V2x,T2x)

CALL Rf(0,Vt)

WAIT 1 CALL Dvm(Vlxf,Tlxf)

OUTPUT 722; "CHAN 1" WAIT .2 CALL Dvm(Vlf,Tlf)

[Tlfac=(T2x-Tli)/(Tlf-Tli)

Vlc=Vli+Tlfac*(Vlf-Vli)

IT2fac-(T2x-Tlxi ) /(Tlxf-Tlxi

]

Vlx=Vlxi +T2fac* (Vlxf- Vlxi

)

Dvl=(Vlf-Vli)*l.E+6

Ovl_dt=Ovl/(Tlf-Tli) 0v2=V2x-Vlx

ICALL Errors

I

[Calls for rf ON and determines when

[For source to settle

[Read delta V2 (V2x) with rf on [Calls for rf OFF and determines when

[Wait again

[Final delta VI (Vlxi) with rf off [Reconnect for VI

[Final VI with rf off

[First timing factor

1V1 corrections

I Second timing factor

[Delta V corrections

[Change in VI [Drift rate of VI in mV/sec

[Change in V2 - (delta V)

[Calculate errors

18
890 Pl=1000/R0*(2*Vlc-(Dv2))*(0v2) IPower in mW

895 Pl=Pl/Cf ICal factor correction

900 t 905 GOSUB Printout I Print results

910 SUBEXIT t Normal exit 915 P: [Printout

920 Printout: I 925 IMAGE 30, 5X, Z.6D, 5X,S2Z. 3D, 8X, Z. 60, 2X, 3D. 30, 5X, S2D.D, 8X, 20. 3D 930 PRINT USING 925;N,Pl,100*(Pl-P0)/P0,Vlc,0v2*l.E+3,0vl_dt,Vlx*l.E+3

935 RETURN t 940 I 945 Bail_out: Us it says

950 OUTPUT 722; "TRIG AUTO" 10VM continue reading

955 PRINT

960 PRINT TABXV(30,1),CHR$(128);CHR$(136);" MEASUREMENT STOPPED

965 PAUSE

970 I 975 Exit: I Finished

980 SUBENO t SUB Meas

985 j*********************************

990 I 995 Rf:SUB Rf(On.Vt) ITurn rf ON/OFF 1000 IF On THEN

1005 OISP CHR$(129);" TURN RF ON (PRESS 8502A KEY '7') ";CHR$(128) ITell operator

1010 BEEP 1000,. 01 I Get his attention

1015 LOOP IWait for rf to be turned on/off

1020 CALL Dvm(V,T) J Read OVM 1025 WAIT 1 I 1030 EXIT IF V>Vt I If rf is turned ON 1035 END LOOP 1040 ELSE

1045 OISP CHR$(129);" TURN RF OFF (PRESS 8502A 'CLEAR') ";CHR$(128) ITell operator

1050 BEEP 1000,. 01 IGet his attention

1055 WAIT .2 1060 BEEP 1000,. 01 1065 LOOP IWait for rf to be turned on/off

1070 CALL Dvm(V,T) I Read DVM 1075 WAIT 1 I 1080 EXIT IF V<Vt I If rf is turned OFF 1085 ENO LOOP 1090 ENO IF 1095 OISP "" 1100 SUBENO

1105 [*********************************

1110 I 1115 Dvm:SU8 Dvm(V,T) I OVM reading

1120 SEND 7;UNL LISTEN 22 IGet dvm's attention

1125 TRIGGER 7 Itrig to read

1130 ENTER 722;V {Read OVM 1135 T=TIMEDATE IGet the time

1140 SUBENO

1145 [*********************************

1150 I 1155 Init:SUB Init Unitialize instruments

1160 I 1165 CLEAR 722 t CI ear 3457 1170 OUTPUT 722; "TERM SCANNER" (Connect input to scanner

1175 OUTPUT 722;"NPLC 10" 110 PLC

1180 OUTPUT 722; "OCV -1" lAuto Range

1185 OUTPUT 722;"TRIG AUTO" tSet up for single readings

1190 I 1195 OUTPUT 722;"CHAN 1" [Connect for VI, floating DVM 1200 WAIT 1 (Make sure everything is settled

1205 SUBENO

1210 i*********************************

1215 I 1220 H:SUB Hdr 1225 I 1230 OPTION BASE 1 1235 CLEAR SCREEN

1240 I 1245 COM /Dvm/ P0,R0,A1,A2,A3,A4,A5,B1,B2,B3,B4,B5,R1,R2,R3,R4,R5

1250 COM /Dvm/ Dvm_name$[40] I DVM ID 1255 COM /Mount/ Mount$[40],Cf I Mount ID 1260 COM /Wavetek/ Sn$[7] IFor the serial number

1265 I 1270 PRINT TABXY(1,1),CHR$(137)&"P W R _ M T R 1"&CHR$(136)

1275 PRINT TABXY(30,1),CHR$(136);CHR$(129);" MEASUREMENT IN PROGRESS ";CHR$(128)

1280 I

19
12B5

1290

1295

1300

1305

1310

1315 1320

1325 1330

1335

1340

1345

1350

1355 1360

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1380 1385

1390 1395

1400

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1430 1435

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1465 1470

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1505 1510

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1655 1660

1665 1670

1675

PRINT TABXY(1,3),CHR$(140);"M0UNT: ";Mount$;CHR$(136) PRINT TABXY(59,3),CHR$(140);TIME$(TIME0ATE);" , ;DATE$(TIMEDATE);CHR$(136)

PRINT TABXY(1,4),CHR$(140);"P0WER METER: WAVETEK MODEL B502A, S/N ";Sn$;CHR$(136)

IDIM A$[80],B$[80],C$[B0],D$[80],Scr$[80] [String variables to build IMAGE statement

Ima:0ATA "#,"" N0."",4X,"" POWER "\4X, ""PWR-""" Imc:0ATA "#,

u mW"",6X, "" VI "",3X,""Delta V"\3X, ""VI 0rift"",3X, ""Ref. Offset"""

RESTORE Ima READ Scr$ I Read as IMAGE statement OUTPUT AJ USING Scr$ OUTPUT 8$ USING "#,2D.0";P0

RESTORE Imc READ Scr$ OUTPUT C$ USING Scr$

D$=A$&B$4C$

PRINT D$

(mW) g",4X,"a (%) C",7X,"a (VOLT) g\3X,"a (mV) g",3X,"a (uV/s) Q

n IMAGE "a g\4X,"a ,3X,"a (mV) 5" PRINT USING 1370

I SU8EN0 t Hdr j****************

E:SUB Errors

OPTION BASE 1 COM /Dvm/ P0,R0,A1,A2 / A3,A4 / A5,B1,B2,B3,84,B5,R1,R2,R3,R4,R5

COM /Ovm/ 0vm_name$[40] IDVM ID COM /Errs/ Dp,Vlc,Vli,Vlf,Vlxi,Vlxf,Vlx,V2x,Tlfac,T2fac,Cfu,Mmu

ICALL Sel ect_v(Vli , Aali , Bbli , Ssli

)

CALL Sel ect_v (Vlf, Aalf , Bblf , Sslf

)

CALL Select v(Vlxi,Aalxi,Bblxi,Sslxi)

CALL Select v(Vlxf,Aalxf,Bblxf,Sslxf)

CALL Sel ect_v (V2x, Aa2x, 8b2x, Ss2x)

I

IAa_ - fraction of reading error

I

IIBb_ - fraction of FS error

lSs_ - full scale reading

GOSUB With_rvg

GOSUB Servo errors

Total_error:l Without RVG.

Total =Without+Eerr+Ierr

ISUBEXIT

I With_rvg: Ovli=Aali*Vli+Bbli*Ssli Dvlf=Aalf*Vlf+Bblf*Sslf

I

I Very small error - not used for this application

I sub routine removed

I Eq's derived 900111/FRC

I Delta-V due to initial VI measmnt

1 Delta-V due to final VI measmnt

Dvlxi =ABS(Aalxi *Vlxi ) +Bblxi *Sslxi Dvlxf=ABS(Aalxf*Vlxf)+Bblxf*Sslxf

I Dv2x=A8S ( Aa2x*V2x) +Bb2x*Ss2x

I Dvlc=(l+Tlfac)*Dvli+Tlfac*Ovlf

Dvlx=(l+T2fac)*Dvlxi+T2fac*0vlxf

I

I

I Delta due to initial Vlx measmnt

t Oelta-V due to final Vlx measmnt

t Delta-V due to V2x measmnt

lError in corrected VI lError in delta V correction

t Dpvl=ABS((V2x-Vlx)*0vlc)

Dpvlx=A8S((Vlc-V2x-Vlx)*Dvlx)

Dpv2x=ABS((Vlc-V2x-Vlx)*Dv2x)

Dp=2*(0pvl+Dpvlx+Dpv2x)/R0

Dp=Dp*l.E+3

RETURN

I Delta-power due to VI measmnt errors

1 Delta-power due to Vlx "

! Oelta-power due to V2x "

I Sum (2 & R0 left out above)

I Op in mW

SUBEND

I

I *******************************

Hp3457:SUB Hp_3457 OPTION BASE 1 COM /Ovm/ P0,R0,A1,A2,A3,A4,

COM /Ovm/ Dvm_name$[40]

Dvm_name$="HP 3457"

A5,B1,82,B3,B4,85,R1,R2,R3,R4,R5

IDVM ID

IFOR DVM: VALUE QUANTITY (HP 3457, 1 yr, 167 ms, 6-1/2 dig)

Nc: DATA 3.03E6 I number of counts, full scale

Al: DATA 4.5E-5 I fraction-of-rdg error, range Rl, 1 yr

A2: DATA 3.5E-5 t fraction-of-rdg error, range R2, etc.

A3: DATA 2.5E-5 1 fraction-of-rdg error, range R3

A4: DATA 4.0E-5 I fraction-of-rdg error, range R4

A5: DATA 5.5E-5 t fraction-of-rdg error, range R5

81: DATA 3B5. I fraction-of-FS error, counts, range Rl, 10 PLC

B2: DATA 40. I fraction-of-FS error, counts, range R2

83: DATA 7. I fraction-of-FS error, counts, range R3

20
1680 84: OATA 20. I fract1on-of-FS error, counts, range R4 1685 85: OATA 7. I fraction-of-FS error, counts, range R5 1690 Rl: DATA 0.0303 I lowest range (including overrange), volts

1695 R2: OATA 0.303 I next range up 1700 R3: DATA 3.03 I next range up 1705 R4: DATA 30.3 t next range up

1710 R5: DATA 300. I next range up 1715 READ Nc,Al,A2,A3,A4,A5,Bl,B2,83,B4,B5,Rl,R2,R3,R4,R5

1720 I 1725 Convert_fs_errs: t Normalize FS count errors to fractional errors

1730 Bl=61/Nc

1735 B2=B2/Nc

1740 B3=B3/Nc

1745 B4=B4/Nc

1750 85=B5/Nc

1755 SU8EN0

1760 t 1765 Select:SUB Select v(V,Aa,8b,Ss)

1770 OPTION BASE 1 1775 COM /Dvm/ P0,R0,A1,A2,A3,A4,A5,B1,B2,B3,B4,B5,R1,R2,R3,R4,R5

1780 COM /Ovm/ Dvm_name$[40] I0VM ID 1785 SELECT ABS(V) I V may be of either polarity

1790 CASE <=R1 I Start at lowest range

1795 Aa=Al I Fraction of rdg error for V on range Rl 1800 Bb=Bl I Fraction of FS error for V on range Rl 1805 Ss«Rl I Full scale reading for V, range Rl 1810 Range=l I Range_no number for plot

1815 CASE <»R2 I Uprange if necessary

1820 Aa--A2 1825 Bb*B2

1830 Ss«R2 t Etc. for range R2 1835 Range=2

1840 CASE <*R3 I And again

1845 Aa=A3

1850 Bb*B3

185S Ss=R3

1860 Range»3

1865 CASE <»R4

1870 Aa=A4

1875 Bb=B4

1880 Ss=R4 1885 Range=4

1890 CASE <=R5

1895 Aa=A5

1900 Bb=B5

1905 Ss=R5

1910 Range=5

1915 CASE ELSE

1920 BEEP

1925 PRINT "Voltage is in excess of 300 volts. Don't be ridiculous."

1930 PAUSE

1935 END SELECT

1940 SUBEND

1945 I 1950 S:SUB Set_up Unitialize mount parameters

1955 OPTION BASE 1 1960 COM /Ovm/ P0,R0,A1,A2,A3,A4,A5,B1,B2,B3,B4,B5,R1,R2,R3,R4,R5

1965 COM /Ovm/ 0vm_name$[40] !DVM ID 1970 COM /Errs/ 0p,Vlc,Vli,Vlf,Vlxi,Vlxf,Vlx,V2x,Tlfac,T2fac,Cfu,Mmu

1975 COM /Mount/ Mount$[40],Cf

I960 Mount$="HP 847BB, S/N 2106A20054"

1985 Cf=.9B97 (Mount calibration factor

1990 Cfu=.5973 [Calibration factor uncertainty in %

1995 Mmu=.21 IMismatch factor uncertainty in % 2000 R0=200 [Mount operating resistance in ohms

2005 P0=1.0 [Comparison power in mW. Note that 2010 [the following line limits this setting

2015 [to a 0.1 mW resolution.

2020 P0=0R0UND(P0,2) [Limit PO to 1 place beyond decimal 2025 SUBEND

2030 I 2035 Stats:SUB Stats(REAL P(*)) 2040 OPTION BASE 1 2045 COM /Ovm/ PO,R0,Al,A2,A3,A4,A5,Bl,B2,B3,B4,B5,Rl,R2,R3,R4,R5

2050 COM /Ovm/ Dvm_name$[40] I DVM 10 2055 COM /Errs/ Dp,Vlc,Vli ,Vlf,Vlxi,Vlxf,Vlx,V2x,Tlfac,T2fac,Cfu,Mmu

2060 ALLOCATE Dum(SIZE(P,l),l) t Use Dum(*) to preserve P(*) 2065 GOSUB Sd I Standard dev. of original set 2070 [

21
2075

2080 2005

2090 2095

2100

2105

2110

2115

2120

2125

2130

2135

2140

2145 2150

2155

2160 2165

2170

2175 2180

2185

2190

2195

2200

2205

2210

2215 2220

2225

2230 2235

2240

2245 2250

2255

2260 2265

2270

2275 2280

2285 2290

2295

2300 2305

2310

2315

2320

2325

2330

2335 2340

2345

2350

2355 2360 2365

2370 2375

2380 2385

2390

2395 2400

2405

2410

2415 2420

2425

2430

2435

2440

2445

2450 2455

2460

2465

Sys_err=Cfu+Mmu+100*Dp/Mean

Sdm=Sd/SQR(SIZE(P,l))

t Systematic error % (See header notes)

I Standard Oeviation of the mean

Tot_unc=Sys_err+300*(Sdm/Mean) [Total uncertainty % with 3*SD mean

I (Print results

r,",3X,"a (%) Q\3X/a (%) g\3X,"a (*) 5"

G0SU8 Prt DEALLOCATE Dum(*) SUBEXIT

I Prt:PRINT " " PRINT "RESULTS:"

IDIM A$[128],B$[12B],C$[128],D$[128],Scr$[128] [String variables to build IMAGE statement

Imd:DATA "#,BX, ""AVG PVR "\4X, " "AVG- 1""1 ImerDATA "#," n mW"",6X,"" MAX OEV " n ,3X, n "ST0 DEVn ",3X, ""SYS UNC"\ 3X, ""TOT UNC

RESTORE Imd READ Scr$ IRead as IMAGE statement OUTPUT AJ USING Scr$ OUTPUT B$ USING "#,2D.0";P0

RESTORE Ime READ ScrJ OUTPUT CJ USING Scr$

D$=A$&B$&C$

PRINT D$

IIMAGE 8X,"a (mw) C/,4X/a (%) C/',7X,"a (%) PRINT USING 2195

IMAGE 8X,Z.6D,5X,S2Z.3D,8X,SZ.3D,K,SZ.3D,4X,Z.3D,5X # Z.3D,5X,Z.3D

PRINT USING 2205; Mean, 100* (Mean-PO)/PO,100*Maxpdv/Mean,\ ",100*Maxndv/Mean,100*Sd/Mean,Sys_err,Tot_unc

RETURN

I Sd:I MAT Dum= P Sum=SUM(Dum) I Sum of the elements in P(*) Mean=Sum/SIZE(P,l) I Mean of P(*) MAT Dum= P-(Mean) I Oum(*) contains deviations from mean

Maxpdv=MAX(Dum(*)) I Largest positive deviation Maxndv=MIN(Dum(*)) I Largest negative deviation Maxdv=MAX(ABS(Maxpdv),ABS(Maxndv)) I Largest largest deviation

MAT Dum= Dum . Oum I Dum holds squares of deviations

IF SIZE(P,1)>1.1 THEN I Check for single measurement Var=SUM(Dum)/(SIZE(P,l)-l) I Variance

ELSEVar=SUM(Dum)

END IF Sd=SQR(Var)

Max_al=3*Sd

RETURN

I SUBENO

I Menu2:SU8 Menu2 OPTION BASE 1 Sys_prty=VAL (SYSTEMS ("SYSTEM PRIORITY')) [Determine system priority

t Standard deviation

I Maximum allowable standard deviation

IPost measurement soft keys

Lcl_prty=Sys_prty+l

USER 1 KEYS

KEY LABELS ON FOR N=0 TO 19 ON KEY N LABEL NEXT N ON KEY 1 LABEL " ON KEY 2 LABEL "

GOTO Top

[Set local priority 1 higher for ON KEY

list set of soft keys

[Turn on soft keys

t CI ear keys lOefault destination

I

MENU ",Lcl_prty GOTO Exit PRINT \Lcl_prty G0SU8 Print

Top: LOOP I Wait for input

END LOOP

Print:

KEY LABELS OFF DUMP ALPHA

KEY LABELS ON RETURN

Exit:

KEY LABELS OFF SUBEND

I Menul:SUB Menul(Nt.Quit)

OPTION BASE 1 Sys_prty=VAL(SYSTEM$("SYSTEM PRIORITY")) tOetermine system priority

Lcl_prty=Sys_prty+l (Set local priority 1 higher for ON KEY

ICOM /Wavetek/ Sn$[7] !For the serial number

[Alpha dump

I Turn off soft keys

I As it says

[Turn keys back on

t

I PRE measurement set up & soft keys

22
2470 H f1ag«l I To write menu

2475 USER 1 KEYS list set of soft keys

2480 KEY LABELS ON I Turn on soft keys 2485 FOR N=0 TO 19 I CI ear keys 2490 ON KEY N LABEL "" GOTO T> t Default destination

2495 NEXT N 2500 t 2505 ON KEY 1 LABEL ' SELECT (1)" ,Lcl prty GOSUB Help 2510 ON KEY 2 LABEL " SELECT (2)" ,Lcl_prty GOSUB Sn 2515 ON KEY 3 LABEL ' SELECT (3)" ,Lcl prty GOSUB Change

2520 ON KEY 4 LABEL " SELECT (4)° ,Lcl prty GOTO Exit 2525 ON KEY 5 LABEL ' SELECT (5)" ,Lcl_prty GOTO Quit 2530 I 2535 Top: LOOP I Wait for input

2540 IF M flag=l THEN GOSUB Menu

2545 ENO LOOP

2550 1 2555 Menu: CLEAR SCREEN

2560 PRINT TABXY(5,2),CHR$(129);" P W R _ M T R 1 ";CHR$(128) 2565 CLIP 10,110,24,88 ITo draw a box

2570 FRAME 2575 PRINT TABXY(24,5)," MEASUREMENT MENU " 25B0 PRINT TABXY(20,8),CHR$(129);"(1)";CHR$(128);" WAVETEK OPERATING INSTRUCTIONS"

2585 PRINT TABXY(20,10),CHR$(129);"(2)";CHR$(12B);" INPUT WAVETEK SERIAL NUMBER" 2590 IF Sn$«" THEN 2595 PRINT TABXY(25,ll),"(No S/N in memory)" 2600 ELSE 2605 PRINT TABXY(25,11),"(S/N ";Sn$;" in memory)" 2610 ENO IF 2615 PRINT TABXY(20,13),CHR$(129);"(3)";CHR$(128);" CHANGE # OF MEASUREMENT POINTS" 2620 PRINT TABXY (25, 14), "(Present setting =";Nt;") " 2625 PRINT TABXY(20,16),CHR$(129);"(4)";CHR$(128);" BEGIN MEASUREMENT"

2630 PRINT TABXY(20,1B),CHR$(129);"(5)";CHR$(128);° EXIT PROGRAM" 2635 M_flag»0

2640 RETURN

2645 Sn: I Input the WAVETEK serial number

2650 KEY LABELS OFF I Turn off soft keys

2655 L INPUT "WAVETEK SERIAL NUMBER ?",Sn$[l,7]

2660 Sn$=TRIM$(Sn$)

2665 PRINT TABXY (25, 11), "(S/N ";Sn$;" in memory)"

2670 KEY LABELS ON I Turn keys back on 2675 RETURN 2680 Change: (Change # of meas points

2685 KEY LABELS OFF I Turn off soft keys

2690 INPUT "NUMBER OF MEASUREMENT POINTS ?",Nt 2695 Nt=MIN(Nt,100) 2700 Nt=MAX(Nt,l)

2705 PRINT TABXY(25, 14), "(Present setting =*;Nt;°) " 2710 KEY LABELS ON I Turn keys back on 2715 RETURN 2720 Help: IWith operation of Wavetek

2725 CALL Help 2730 M_flag=l

2735 RETURN

2740 Quit: I Terminate program

2745 Quit=l 2750 Exit: I 2755 KEY LABELS OFF 2760 SUBENO

2765 I 2770 Help:SUB Help 2775 CLEAR SCREEN 2780 OPTION BASE 1 2785 Sys_prty=VAL(SYSTEM$("SYSTEM PRIORITY")) lOetermine system priority

2790 Lcl_prty=Sys_prty+l I Set local priority 1 higher for ON KEY 2795 USER 1 KEYS list set of soft keys

2800 KEY LABELS ON I Turn on soft keys

2805 FOR N=0 TO 19 I CI ear keys 2810 ON KEY N LABEL "" GOTO Top I Default destination

2815 NEXT N 2820 ON KEY 1 LABEL "CONTINUE", Lcl_prty GOTO Exit 2825 GOSUB Text I Print info 2830 I 2835 Top: LOOP I Wait for input 2840 ENO LOOP 2845 I 2850 Text:PRINT TABXY(22,2), "CONTROLLING 8502A CALIBRATOR OUTPUT" 2855 PRINT TABXY (12, 4), "Press the following B502A front panel control keys in the" 2860 PRINT TABXY(12, 5), "sequence indicated:"

23
2B65 PRINT TA8XY(14,7),"(1)-'CV',"

2870 PRINT TABXY(25,7),"(2)-'Henu',"

2875 PRINT TABXY(38,7),"(3)- 'F3',' 2880 PRINT TABXY(49,7),"(4)-'F1'."

2885 PRINT TABXY(12,9),"Then, pressing the 8502A key '7' will turn the calibrator"

2890 PRINT TABXY(12,10), "output ON, and pressing the 8502A key 'CLEAR' will turn the" 2895 PRINT TABXY(12, 11), "calibrator output OFF." 2900 PRINT TABXY(12,13),"For more detail see 'Calibrator Output Level Test' on page 6-2" 2905 PRINT TABXY(12,14),'of the 8502A manual."

2910 PRINT TABXYC12, 17), "CAUTION: Do not press any UNITS key when the mount is" 2915 PRINT TABXY(12,18), "connected to the calibrator. This will cause the" 2920 PRINT TA8XY(12, 19), "calibrator to output 100 mW which might damage the mount."

2925 RETURN

2930 I 2935 Exit: I 2940 SUBENO

24
BL-114A

(5-90) U.S. DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

BIBLIOGRAPHIC DATASHEET

1. PUBUCATION OR REPORT NUMBER

SIST/TN-1345

2. PERFORMING ORGANIZATION REPORT NUMBER

PUBUCATION DATE November 1990

4. TITLE AND SUBTITLE

Power Measurement System for 1 mW at 1 GHz

5. AUTHOR(S)

Fred R. Clague

6. PERFORMING ORGANIZATION (IF JOINT OR OTHER THAN NIST, SEE INSTRUCTIONS)

U.S. DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

BOULDER, COLORADO 80303-3328

7. CONTRACT/GRANT NUMBER

8. TYPE OF REPORT AND PERIOD COVERED

SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (STREET, CITY, STATE, ZIP) D. S. Air Force

Logistics Command

Directorate of Metrology

Newark AFB, Ohio 43057

10. SUPPLEMENTARY NOTES

11. ABSTRACT (A 200-WORD OR LESS FACTUAL SUMMARY OF MOST SIGNIFICANT INFORMATION. IF DOCUMENT INCLUDES A SIGNIFICANT BIBLIOGRAPHY OR

LITERATURE SURVEY, MENTION IT HERE)

An automated measurement system designed to measure power accurately at the level

of 1 mW and at the frequency of 1 GHz is described. The system consists of

commercial IEEE Std-488 bus-controlled instruments, a computer controller, and

software. The results of a series of measurements are output to the computer display

and, optionally, to a printer. The results are the mean of a measurement series and

and estimate of the systematic and random uncertainty. The total estimated uncertainty

for the average of six consecutive measurements of a nominal 1 mW, 1 GHz source is

typically less than 1 percent. The system can measure any power from 0.1 to 10 mW

at any microwave frequency by making appropriate changes to the software and

possibly, the hardware.

12. KEYWORDS (6 TO 12 ENTRIES; ALPHABETICAL ORDER; CAPITALIZE ONLY PROPER NAMES; AND SEPARATE KEY WORDS BY SEMICOLONS)

automated measurement; microwave; microwave power measurement; power; power measurement;

power measurement system.

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14. NUMBER OF PRINTED PAGES

15. PRICE

ELECTIRONIC FORM •&U.S. GOVERNMENT PRINTING OFFICE: IWI - 574-O20/45OM

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