Test Report H25DSS950TX

FCC ID: H25DSS950TX

Test Report

Download: PDF
FCCID_89389

                                                                                     H25DSS950TX


                              TEST DATA for H25DSS950TX


I.   INTRODUCTION

These tests were conducted on a sample of the H25DSS950TX spread spectrum audio
transmitter, for the purpose of demonstrating compliance with the requirements of Part 15
Certification and tested to Part 2 of Title 47 of the CFR. The H25DSS950TX transmitter is a
Binary Phase Shift Keyed (BPSK) direct sequence spread spectrum intentional radiator with a
rated output power of 500 mW. This device operates on three channels in the 902-928 MHz
band. This transmitter is marketed only to the police radio service and government agencies for
short-term surveillance and personal protection applications in concert with receiver FCC ID:
18WWRM91-50, also marketed by DTC Communications, Inc.

All testing was conducted at DTC Communications, Inc.; 75 Northeastern Blvd., Nashua, NH
03062 with the exception of the radiated spurious testing, which was, performed at the OAT site
at Retlif Laboratories Goffstown, NH facility. Retlif Testing Laboratories is listed by the FCC as a
facility available to do measurement work for others on a contract basis.


II. INFORMATION REQUIRED FOR CERTIFICATION

Para.

2.10033(a)      This Application for Certification is filed on form 731 with all questions answered.
                Confidentiality is being requested for the schematic. An application fee of $940
                and a request for confidentiality of $135 is attached.

2.10033(b)(1)   The full name and address of the applicant and manufacturer for certification is:

                         DTC Communications Inc.
                         75 Northeastern Blvd.
                         Nashua, NH 03062

        (2)     The FCC Identifier of the device is H25DSS950TX

        (3)     A copy of the operating instructions is included in the EXHIBITS.

        (4)     Circuit Functions and Operation

The H25DSS950TX is designed to operate as a portable direct sequence spread spectrum
radiator in the 902-928 MHz band. The antenna is an integral patch, attached to the enclosure.
This unit is battery powered. A description of the circuit functions follows:

The H25DSS950TX is a low power, spread spectrum audio surveillance transmitter used for law
enforcement applications. The transmitter employs digital modulation with direct sequence spread
spectrum on one of three factory-selected channels. It has a peak power output of 500mW to an
integral patch antenna and meets the requirements of Part 15.203.

Two microphone modes are supported, internal and external. The microphone audio is processed
by an amplifier equipped with an automatic gain control (AGC) which may be turned ON or OFF
with an external switch. Audio is processed with a continuously variable slope delta-modulation
(CVSD) speech coder at a rate of 32 Kbps. Radiated testing was performed with the external
microphone connected.


                                                                                      H25DSS950TX


The H25DSS950TX is powered by three AA batteries, which supply a nominal 4.5 VDC. All
critical circuits are regulated.

Necessary Bandwidth

This is a digitally modulated device. The modulation method is binary phase shift keying (BPSK)
with direct sequence spreading based on a pseudorandom code. The occupied bandwidth is
related to the coded voice data rate along with the number of spreading chips per bit and system
filtering. The chips per bit times the data rate known as the chip rate or code rate is the dominant
factor since it does the actual “spreading”.

The audio data converter rate is 32 Kbps. The effective number of chips per bit is 11.

The code rate is the data rate times the chips per bit or 357.1 K chips per second (cps).

The necessary bandwidth calculation for the H25DSS950TX transmitter follows the general
formula for direct sequence transmitters:

                                   BW = 2 X code rate

Because of the use of a proprietary technique called recombinant spread spectrum (RSS), which
improves fade resistance, the chip clock rate appears to be higher than 357.1 Kcps, actually 704
Kcps, so far as occupied BW is concerned. So the necessary bandwidth is:

                              BW = 2 (704 Kcps) = 1.4 MHz

Emissions Designator
Part 15 does not require an emissions designator.

A representative emissions designator is: 1M4G1D

This indicates that this is a binary phase shift keyed, single channel, digital transmission, with an
occupied bandwidth of 1.4 MHz.

The actual bandwidth including major sidelobes, measured at the 6dB points, is just over 1 MHz.
This bandwidth meets the requirements of §15.247(a)(2).

RF Radiation Exposure Evaluation

§15.247(4) states that systems shall be operated in a manner that ensures that the public is not
exposed to radio frequency energy levels in excess of the Commissions guidelines.

The H25DSS950 was tested to ANSI/IEEE C95.1-1992 at PC Test Labs.and was found to be
within the SAR limits for uncontrolled exposure when the transmitter is properly used. The SAR
test report is a located in a separate EXHIBIT from the test data.

This transmitter employs a patch antenna, which radiates more than 80% of the RF energy away
from the body. This fact coupled with the low average power, and limited mission time, insures
that exposure levels are well below the SAR limits of §2.1093(1) and ANSI/IEEE C95.1-1992.

The instruction manual includes safety warnings and a description of how to properly mount the
transmitter on the body, so as to minimize exposure and maximize outward radiation. In addition,
the transmitter is equipped with a “This Side on Body” warning label as shown in the photo
EXHIBITS.


                                                                                   H25DSS950TX


        (5)     A block diagram of the device is included in the EXHIBITS.

        (6)     This Test Report includes tabular data and plots.

        (7)     Internal and external photographs of this device are included in the EXHIBITS.

        (8)     No peripherals, other than the external microphone, were involved in this
                evaluation.

        (9)     Certification under the transition provisions of Paragraph 15.37 is not being
                requested for this device.

        (10)    The Processing Gain of the H25DSS950TX exceeds 10 dB.


Processing Gain

Processing gain in a direct sequence spread spectrum transmitter is 10log (chips per bit).

                                       10log(11) = 10.4dB

This processing gain is more than 10dB and thus meets the requirements of Part 15.247(e).

The transmitter and receiver system components provided by Digital Wireless Corporation, have
been previously certified under Part 15 and have been found to provide an acceptable processing
gain when used as a system. Data from FCC ID: 18WWRM91-50 for jamming measurements
follows:




               GAMBATTE INC. TRADE SECRET INFORMATION

                                         Processing Gain
                                              in the
                                         WRM91 Receiver

        This document contains Trade Secret and/or Company Confidential information.
We request that the contents of this correspondence and all related correspondence be
withheld from public inspection as provided under Section 0.457, as requested in the
application for Part 15 intentional spread spectrum radiator certification for FCC ID:
I8WWRM91-50.

        FCC Part 15.247, amended June 14, 1990, requires that direct sequence spread
spectrum (DS/SS) receivers exhibit at least 10 dB processing gain. Processing gain in
DS/SS systems is defined as the difference between receiver input signal to noise ratio
and post-correlation signal to noise ratio. The Rules state that processing gain shall be
determined from the ratio of the signal to noise ratio with the system spreading code
turned off and the signal to noise ratio with the system spreading code turned on, as
measured at the demodulated output of the receiver." In many systems, including the
subject WRM91 receiver, the signal to noise ratio cannot be measured with the spreading
code "turned off" because the code is permanently programmed into a digital FIR filter.


                                                                             H25DSS950TX



            GAMBATTE INC. TRADE SECRET INFORMATION

        If the FIR filter clock is disabled to "turn off" the spreading code, the FIR filter
will be disabled, making any measurement of signal to noise ratio impossible.

        As an alternative, measurement a related quantity -- jamming margin -- provides a
convenient substitute measurement. Jamming margin is generally considered a valid
substitute measurement of realized processing gain. Jamming margin is often a function
of the nature of the jamming signal. The use of a CW jammer for jamming margin
measurements is simple and straightforward and is meaningful and repeatable. Using a
Jammer and measuring system bit error rate (BER) as a function of the signal interference
(S/I) ratio or its converse, the jam to signal (J/S) ratio, provides an indication of a
receiver's ability to resist jamming.

        Digital communications systems exhibit a BER threshold effect: They perform
well in the presence of noise or jamming up to a certain point, then BER precipitously
deteriorates. The theoretical 10-5 BER threshold for BPSK systems is about 9.6 dB. Most
commercial systems, for reasons relating to practical and economic aspects of
commercial-quality circuit realization, exhibit a 10-5 BER at approximately 12 to 14 dB
S/I. Using this as a standard, a spread spectrum system that exhibits a 10-5 BER at an
input S/I ratio in the range of 2 to 4 dB has probably achieved 10 dB jamming margin
and, by inference, 10 dB of processing gain.


Measurements of WRM91 receiver jamming margin were made using a Hewlett Packard
8656B UHF synthesizer as a jammer The results are shown in the tables and graphs on
the following pages. The RMS powers of the jammer and the signal were measured
precisely for the tests using a, Hewlett Packard Model 438A RF power meter which is
has 0.01 dB resolution, It can be seen that the minimum 10 dB margin requirement is met
or exceeded at all frequencies, Out-of-band rejection is very exceptionally high, requiring
a jamming (blocking) signal of -2 dBm or so to Jam the desired signal (-20 dBrn blocking
is considered excellent for most commercial or industrial receivers),

       We have submitted data on the CW Jamming margin of the WRM91 receiver
in-band and out-of-band in order to demonstrate that its a very robust receiver. We
submit the following data and information as evidence that the WRM91 receiver does
indeed possess at least 10 dB processing gain:

       1) The spreading ratio of the WRM91 transmitter is 14 (18.6 dB), thus 10 dB is
          theoretically achievable.


            GAMBATTE INC. TRADE SECRET INFORMATION


                                                                                                        H25DSS950TX



                GAMBATTE INC. TRADE SECRET INFORMATION
          2) The system exhibits less than 10-5 BER at 2.1 dB S/I typical, 3.8 dB worst
             case with a CW jammer, This is indicative of a 11.9 dB typical and 10.2 dB
             worst case assuming that 14 dB S/N is necessary at the demodulator for 10-5
             BER.

          3) The receiver is a well-designed, industrial-quality single conversion
             superheterodyne design. It uses a high-intercept-point RF preamp and mixer, a
             high rejection SAW IF filter, insuring that it has no significant response (as is
             demonstrated by the out-of-band CW interference measurements) to
             out-of-band signals.

          4) The receiver employs a differential demodulator with a 2:1 input/output
             symbol ratio followed by a 37-tap FIR filter correlator for a net 74:1 input
             output symbol ratio. It also features a post-correlation integrate-and-dump bit
             decision circuit (as opposed to simple threshold detection) to insure that as
             much as possible of the post-processed energy is recovered and utilized in
             making the bit decision,

          5) The system's 74-elernent spreading code was designed by computer and was
             chosen for its random spectral distribution properties, 1/0 code balance, and
             excellent even and odd correlation characteristics.


              We submit that our CW jamming margin measurements are a valid
demonstration of the WRM91 receiver's having met the 10 dB processing gain
requirement of FCC Part 15.247, as amended June 14, 1990.
                                          Respectfully submitted,




                                                              P. Stuckey McIntosh
                                                              Chairman
                                                              Gambatte Digital Wireless




This document contains Trade Secret and/or Company Confidential Information. We request that the contents of this
correspondence and all related correspondence be: withheld from public ins pection as provided under Section 0 457, as
requested in the application for Part 15 intentional spread s pectrum radiator ce rtification for FCC ID: I8WWRM91-50.




              GAMBATTE INC TRADE SECRET INFORMATION


                                                                   H25DSS950TX


JAMMING MEASUREMENTS OF THE WRM91 SYSTEM
Frequency(MHz)                         CW Jammer Level
                                        (Dbm Relative to Signal)
 900                                          30
 902                                          30
 903                                          30
 904                                          30
 905                                          30
 906                                          30
 907                                          30
 908                                          30
 909                                          30
 910                                          30
 911                                          30
 912                                          30
 913                                          30
 914                                          30
 914.4                                        3.9
 914.45                                       0.9
 914.5                                        0.9
 914.55                                       0.9
 914.5                                        -1.1
 914.65                                       -2.1
 914.7                                        -2.1
 914.75                                       -2.9
 914.3                                        -2.9
 914.85                                       -2.9
 914.9                                        -3.8
 914.95                                       -2.9
 9113                                         -2.1
 915-05                                       -2.1
 915.1                                        -3.8
 915.15                                       -3.8
 915.2                                        -1
 915.25                                       -1
 915.3                                        -2.9
915.35                                        1.1
915.4                                         1.1
915.45                                        0.1
915.5                                         0.1
915.55                                        1.1
915.6                                         1.1
915.65                                        1.1
915.7                                         2.1
915.75                                        2.1
915.8                                         4.7
916                                           30
917                                           30
918                                           30
919                                           30
920                                           30
921                                           30
922                                           30
923                                           30
924                                           30
925                                           30


                                                                                                 H25DSS950TX


926                                                                          30
927                                                                          30
918                                                                          30
930                                                                          30
931




         This document contains Trade Secret and or Company Confidential information. We request that the
contents of this correspondence and A related correspondence be withheld from public inspection as provided
under Section 0.457, as requested in the application for Part 15 intentional spread spectrum radiator certification
for FCC ID I18WWRM91-50.


                   GAMBATTE INC TRADE SECRET INFORMATION


                                                                                                 H25DSS950TX




         This document contains Trade Secret and or Company Confidential information. We request that the
contents of this correspondence and A related correspondence be withheld from public inspection as provided
under Section 0.457, as requested in the application for Part 15 intentional spread spectrum radiator certification
for FCC ID I18WWRM91-50.


                   GAMBATTE INC TRADE SECRET INFORMATION


                                                                                    H25DSS950TX



         (11)    N/A



III. TEST RESULTS


a) The minimum 6dB bandwidth per §15.247(a)(2) is given in Plot 1. This 1MHz-plus occupied
   bandwidth meets the minimum 500 kHz requirement for DSSS transmitters.

b) Peak power within the band 902 – 928 MHz has been measured with a spectrum analyzer.
   The results are shown in Plot 2. All measurements are with an external attenuation of 30 dB
   so the top of the graph is +30 dBm. The average power of the transmitter, as measured on a
   power meter was 0.467 W. This output power is below the 1 Watt limit of §15.247(b)(1).

c)    Spurious emissions were measured over the frequency range of 30 – 9280 MHz per
     §15.247(c) as shown in Plots 5-8. Conducted spurious emissions are all greater than 55 dBc.

d) Per §15.247(d), the transmitter power spectral density averaged over a one -second interval
   in a 3 kHz band is given in Plot 9. The + 4 dBm peak level is below the + 8 dBm limit.

e) Conducted voltage measurements per §15.207(a), N/A – this is a portable, battery operated
   device.

f)   Radiated field strength measurements were taken in the range 30 MHz – 1000 MHz per
     §15.109(a). This testing was performed by Retlif Labs. at their Goffstown, NH site. A
     complete test report is attached which includes test photographs and a test equipment list.
     All correction factors are included in the measurement results. All detected spurious
     emissions were within Part 15 limits including restricted band limits.


                                                                                H25DSS950TX


a. Minimum 6 dB Bandwidth

   This measurement was done with 30 dB of external attenuation between the test sample and
   the spectrum analyzer. The integral antenna connection was removed from the transmitter
   output and a test cable pigtail was substituted. This bandwidth (1 MHz), is greater than the
   minimum 6dB bandwidth of 500 kHz required by §15.247(a)(2).



                               Plot 1 Minimum 6dB BW


                                                                               H25DSS950TX



Peak Power Measurement

The peak power measurement was made with 30 dB of attenuation between the test sample and
the spectrum analyzer. Thus the peak output power is –3 dBm + 30 dB = 27dBm or 0.500 W.


                                     Plot 2 Peak Power




Conducted Spurious Emissions

Measurements were done with 30 dB external attenuation in a frequency range of less than 10
MHz to greater than 9280 MHz.


  CTR        50 MHz      SPAN 10 MHz/            RES BW 100 kHz        YF OFF
  REF     0 cBm       10 dB/        ATTEN 10 dB           SVP   AUTO




   w     MaArcmd                       bubhseiretiihare                 fouiAtund


  CTR      300 MHz      SPAN 18 MHz/             RES BW 100 kHz        YF DFF
  REF     D dBm       10 dB/        ATTEN 10 dB           SWP   AUTO




houtalinatnooterwe       tscdbwat               bowadshy                Ifadicanta


CTR 800 MHz        SPAN 50 MHz/      RES BW 100 kHz   VF OFF
REF O cBi       10 dB/     ATTEN 10 dB    SWP AUTO




                       i
                 frimc h              m COs
CTR 1.300 CHz      SPAN 100 MHz/     RES BW 100 kHz   VF OFF
REF 0 dBm       10 dB/     ATTEN 10 dB    SWP AUTO


| CTR 2.300 CHz                 SPAN 100 MHz/         RES BW 100 kHz        VF OFF
   REF          0 dBm         10 dB/        ATTEN 10 dB    SWP   AUTO




                        flw‘            wmwvw!vm/ww                      y



   CR           3300 6Hz         SPAN 100 MHz/        RES BW 100 kHz        VF OFF
   REF O cBin                 10 dB/        ATTEN 10 dB    SWP   AUTO




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              Olny dAS     8P O N1¥       /8P 01                 "gP 0 434
 430 3A       4M OUUL MB SI8    /ZHW 002 NYdS                 49 O0L‘S H1]
                                                      talas               M
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              olny dM5 8P Of NaLly     /8P O1    "oP 0 438
 45C 4A       2HM 001 Md 534 /2HW 001 NYIS    49 00E ¢ W13


  CTR 7.700 GHz             SPAN 200 MHz/       RES BY 100 kHz   VF OFF
  REF 0 cBm              10 cB/       ATTEN 10 cB    SWP AUTO




wfthory hrediafst   omm vaadtrn notigeeNlyhatsh   wlamtheintye   l




  CTR 9.700 CHz             SPAN 200 MHz/     RES BW 100 kHz     YF OFF
  REF 0 dBm              10 dB/     ATTEN 10 dB    SWP AUTO




           Y


                                                                               H25DSS950TX


b. Power Spectral Density was done with 30 dB of attenuation between the test sample and the
   spectrum analyzer. Peak spectral power is no greater than +4 dBm, thus meeting the + 8
   dBm limit.


                               Plot 13 Power Spectral Density




Band Edge Spectral Data

Conducted band edge data were taken with the transmitter set for Channel 1 (905.5Hz) and
Channel 3 (924.5 MHz). This test was done with 30 dB of attenuation between the test sample
and the spectrum analyzer. The peak power at the band edges is greater than –30 dBc on the
lower edge and -25 dBc on the upper edge, thus meeting the – 20 dBc minimum of 15.247c.


[
    CTR       902 Wz           SPAN 1 MHz/   RES BW 30 kHz       VF OFF
 REF 0 dBm                  10 dB/ ATTEN 10 48 SWP_ AUTO
_
          |

                                                                 tA
                  |                                              tA
                  ||                              j         7\
                                     A, M\            /N\
                                       Y¥ ¥ N N
          o‘ y
[ VW
    CTR 928 WHe     SPAN 1 MHz/  RES BW 30 kHz                   VF OFF
    REF 0 dBm   10 dB/ ATTEN 10 dB SWP_ AUTO


                       /A


                                                 H25DSS950TX


Conducted Voltage - N/A

c.   Radiated Spurious Emissions (Retlif Labs)


                   101 Naw Boston Road, Goffetown, NH 03045
                                                                                wtouear
                                                                                PCtca
                   600—07—4800 — Fac eos—w0r—z001                              lndndticSmabad
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                                         DATA PACKAGE
                                              FOR

                                      Digital Spread Spectrum
                                   Audio Surveillance Transmitter
                                          Modei No. DSS9SOTX




               Customer Name:              DJCInc...............___________.
                                                    Com unications,

               Customer P.0.;              s5zo1
               Date Package No.:RB§2N
               Package Date:               March 1, 2000
               Test Start Date:            February 24, 2000
               Test Finish Date:           February 24, 2000_                         _
               Test Technician(@y:____....
               Test Engineer:              John Monahn
               Data Prepared By:           Term G. Tarango
               Supervisor.                 Seott Wentworth
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  «n                                       eeerenernt


                                     MOBIRICATION TO ThE EUT
                                  MADE DURING THE TEST EROGRAM

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   ‘test Method: _A£—              Techntciom: _Z_*—                           pa: 0 2/2%fe©
   Reason for ModMeation:           Hién    sPuMiob RepmTHD EMISStGRS 1\
    SEvVEmalL.          ResrecmmD           Ranbs          (HARRORICS oF FunQ)



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      FRoM           RF micRopevices                   ZIC&P             To        RF micreDEvices
      2131 P.            ci@cuT beakp                   ufpate To AceePp
     mEw         FeoTPRinT amD HATCHING                          o m PONENTS »
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    unCHanGeD,                Cowse suPPC#                  4NCRngeD \ poTeINA
     uim CHAM E[D 1                  Housin©            UN Ctan 6ED

          Cirele One:
                 Temporary              (Intaled terporarily duringtest evaluntion; manafncturer to
                                        Instapermanenty)
                                        (Insatled permanenty by manutacturer doring tent evalustion)
   Result of Modifcation:               we—       TeE AhPtfr                    re               e
    LINEAR           pevice           REpucen            ALL Spu@S§                wELl inTo
    conPuignce


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                  18 masen,i pary, on Th eresence or ite anove Monteication.


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          imadsavaee oh nee o     the nbove modifcaton incorpenia i allfaureprodecios ofheEUT.

          Customer Initils                         r.               Retlif Testing Laboratories
Moee, MugPhY        DTC       Fommamostieng
          Q. Customer Copy § Leb Copy                            MODIFICATION REVIEW SHEET


                                 EQUIPMENT LIST
                                 Radiated Emnissions
EN    Type             Manofacturer   Progueney Range   ModeiNo.   CalDate   Due Date
J11   boutedresngiie   Heccortesia    man. (om          perioo     emanom    aneame
138   DoileRie O       mco            1—mame            ms         c«mmoms   cumasme
w     Diswiey          mco            mmaoe             ne         cersims   ovisame
495   Spestie tm       HevetPidusd    Ste—tione         ssm        canmem    cuitamm
@21   Ontertine        BevotPaduad    Nh                mm         cvnee     cnsane
16—   nrteen Anijae    Pectnttetics   ovitier on        smoase     cvanse    enc




                                         re              Retlif Testing Laboratories

                                                         DATA PACKAGE No, R—3562N


  sammmmmmm                     _ RETLIF TESTIING LABORATORIES                                                              mmz
                                             30MHz to 10GHz



                             Spread Spectrum Audio Surveillance Transmitter



                        FCC Part 15, Subpart C
                                                                                             PARAGRAPH:        15.247

                                      Transmitting


 AEohnician: .          . Firkowakd                                                    ;
 MO"E&       .    . i           Function: Quask—Peak (30MHz—1GHz)     Test Distance(3OMHz—1GHz): 3 Meters
             :     i                                                                                 1 Meter      See Modification Shoet

   Test           ANTENNA             TURNTABLE                       CORRECTION       CORRECTED                        CONVERTED TO         LIMIT
 FREQUENCY        POSITION             POSTION                          FACTOR             READING                         3 METERS        @3METERS

    Mz           (HV)—HEIGHT           DEGREES                                dB           dBuVim                                           dBuVim




patasHeetr [1] or [1]                                                                                                                      R—3562N


                                                                                    H25DSS950TX


                        EQUIPMENT LIST – Retliff Testing Laboratories

                                   Spurious Radiated Emissions


Type                             Manufacturer             Model Number

Pre-Amplifier                    Miteq                    AFS42-35

Broadband Pre-Amplifier          Electro-Metrics          BPA-1000

Double Ridge Guide               EMCO                     3115

Open Area Test Site              Retlif                   3/10 Meters

Biconilog                        EMCO                     26MHz – 2 GHz

Graphics Plotter                 Hewlett Packard          7550A

EMC Analyzer                     Hewlett Packard          8593EM



III.    MODIFICATIONS

No modifications were made by DTC Communications Inc. or Retlif Testing Laboratories, to bring
the unit into compliance other than those shown on the Retlif Modification to EUT Sheet shown in
the Retlif data package. This modification involved the redesign of the RF power amplifier by DTC
to accept a similar, but more linear, power amplifier MMIC. Approximately one month of time
elapsed between the initial testing and the final testing sessions. All final conducted and spurious
radiation data were taken with the final configuration. A short coaxial jumper made of 7 Inches of
RG-188 with a male SMA connector was substituted for the patch antenna during the conducted
spurious radiation testing.



IV.     DTC TEST EQUIPMENT

Type                             Manufacturer             Model No.


Power Meter                      Hewlett Packard          HP 437B

Spectrum Analyzer                Hewlett Packard          HP 8570A

Multimeter                       Hewlett Packard          34401A

DC Power Supply                  Hewlett Packard          E3610A

Audio Generator                  Leader                   LAG-12S

Temperature Chamber              Associated Systems       BK-1101

Frequency Counter                Systron Donner           6420

Attenuator Pad 30 dB             JFW               50FH-030



Document Created: 2000-03-03 16:59:39
Document Modified: 2000-03-03 16:59:39

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