measurement of the effect of vehicle ignition noise on ... · table 1. 1979 mvma tests test...
TRANSCRIPT
NTIA-Report-80-43
Measu rement of the Effectof Vehicle Ignition Noise
on Land-MobileVoice Channels
w. J. Hartman
u.s. DEPARTMENT OF COMMERCEPhilip M. Klutznick, Secretary
Henry Geller, Assistant Secretaryfor Communications and Intormation
June 1980
PREFACE
This work was done by u. S. Department of Commerce,National Telecommunications and Information Administration,Institute for Telecommunication Sciences, for the MotorVehicle Manufacturers Association of the United States, Inc.,Detroit, Michigan 48202.
iii
TABLE OF CONTENTS
LIST OF FIGURES
LIST OF TABLES
1. INTRODUCTION
2. TEST PROCEDURES
3. TEST RESULTS
4. DISCUSSION OF RESULTS
5. REFERENCES
APPENDIX: AMPLITUDE PROBABILITY DISTRIBUTIONS
v
Page
v
v
1
4
6
8
9
Figure 1.
Figure 2.
Figure Al.
Figure A2.
Figure A3.
Figure A4.
Figure A5.
Figure A6.
Figure A7.
Figure A8.
Figure A9.
Figure AlD.
LIST OF FIGURES
The location of vehicles for the 1979 MVMA tests.
Comparison of the subjective articulation scores (ASwith the objective scores. The straight line wouldbe perfect agreement.
The APD1s for test 1 at 50 MHz with 1 SAE vehicle.V(RMS) = -120.6 dBm.
The APD1s for tests 2 and 3 at 50 MHz with 1 supernoisy vehicle. V(RMS) = -100.6 dBm.
The APD for test 4 at 50 MHz with no vehicles.V(RMS) = -120.4 dBm.
The APD for test 5 at 29 MHz with no vehicles.V(RMS) = -118.5 dBm.
The APD for test 6 at 50 MHz with 6 SAE vehicles.V(RMS) = -119.9 dBm.
The APD for test 7 at 29 MHz with 12 SAE vehicles.V(RMS) = -117.4 dBm.
The APD for test 8 at 50 MHz with 12 SAE vehicles.V(RMS) = -119.7 dBm.
The APD for test 9 at 50 MHz with 11 SAE and1 super noisy vehicle. V(RMS) = -102.9 dBm.
The APD for test 10 at 147 MHz with 12 SAE vehiclesV(RMS) = -118.1 dBm.
The APD for system noise through the filter,amplifier, spectrum analyzer and DM3.V(RMS) = -121.0 dBm.
LIST OF TABLES
Page
2
5
10
11
12
13
14
15
16
17
18
19
Table 1.Table 2.Table 3.Table 4.
Table 5.
1979 MVMA Tests.Voice Scores.Statistical Noise Parameters.Tabulation for Comparison of the Noise StatisticalParameters with the Articulation Scores.Correlation Coefficients for Test 1, 4, 6, 8, and9 Between the Statistical Noise Parameters and theVoice Scores.
vii
2
4
6
7
7
MEASUREMENT OF THE EFFECT OF VEHICLE IGNITION NOISE ONLAND-MOBILE VOICE CHANNELS
*w. J. Hartman
Measurements of the voice intelligibility over landmobile systems in the presence of vehicle noise are presented. These are compared with several statistical noiseparameters obtained from measured amplitude probabilitydistributions.Key words: Impulse noise, intelligibility, scoring,
vehicle noise.
1. INTRODUCTIONTests were run during April 1979, at the GM proving ground near Milford,
Michigan, to determine the effects of automotive ignition noise on the voicechannel performance of land-mobile radios. The Institute for TelecommunicationSciences (ITS) participated in these tests by measuring the amplitude probabilitydistribution (APD) of the noise and making voice recordings for later scoring.The voice intelligibility scoring was done both subjectively (listener panel) andobjectively (Gamauf and Hartman, 1977). The results of these tests are presentedhere.
From the APD, the statistical moments can be obtained and compared with thevoice scoring. Here, we calculate the average V(AVG), the root mean square V(RMS),and the difference Vd = V(RMS) - V(AVG) for comparison.
2. TEST PROCEDURESThe vehicles, antennas, cables, and receivers were provided by The Motor Vehicle
Manufacturers Association (MVMA). A total of 10 test conditions were used, and theseare described in Table 1. The placement of the vehicles is shown in Figure 1. Whena super noise vehicle (SNV) was used, it was placed in position 1, except for thetest condition #9, when it was placed in position 4. The receiving antenna waslocated on the trunk of the test car. The antenna cable was run into a building usedfor the test equipment. The APD tests used the output from the antenna cable as aninput signa 1.
*The author is with the U.S. Department of Commerce, National Telecommunicationsand Information Administration, Institute for Telecommunication Sciences,Boulder, Colorado 80303.
Table 1. 1979 MVMA TestsTest Schedule
Test No. Frequency Vehicles Signal Level(dBm)
1 50 MHz 1 SAE -1082 50 MHz 1 SNV -1083 50 MHz II -984 50 MHz None -1085 29 ~1Hz
II -1016 50 MHz 6 SAE -1087 29 MHz 12 SAE -1018 50 ~1Hz 12 SAE -1089 50 MHz 11 SAE+SNV -108
10 147 MHz 12 SAE -113
BGG1~
EJ G~
8 [~ G8 GG
~3m-+)
12
ITESTICAR
Figure 1. The location of vehicles for the 1979 MVMA tests.
2
For the tests at 50 ~·1Hz, thi s signa 1 was fi rst passed through a tunab1e bandpass filter [Texscan 5 VF 48195-5-CC]1~ then through a fixed (40 dB) gain broadbandamplifier [ENI 411 LA], and into an HP 85588 spectrum analyzer. The 21.4 MHz outputof the spectrum analyzer was then used as input to the noise measuring system, theDM 32. For the 29 MHz and the 147 MHz tests a bandpass filter was not available, butthe rest of the test configuration remained the same.
The DM 3, which was built by the Institute for Telecommunication Sciences for theAir Force, uses an envelope detector to detect th~ IF output voltage, and quantizesthe output of the detector into 15 discrete levels spaced 6 d8 apart. The count ateach level divided by the total count gives the percentage of time that the envelopeexceeds that level. An internal calibration is available for setting the 6 dB steps.
An external calibration was made using a sine wave from a signal generator.This signal was substituted at the input to the filter, or the amplifier as appropriate. This technique allows the calculation of input noise levels and serves as acheck on the internal calibration.
The DM 3 has a bandwidth of approximately 1 MHz. The spectrum analyzer was usedto select the narrow band mode, 30 kHz, for the measurements.
For the voice measurements, the phonetically balanced (PB) word lists were playedfrom a master tape on a lj2-inch recorder. This signal was used to modulate thetransmitter. The audio output of the receiver was recorded on a second identicalrecorder. The master tape had 8 50-word PB word groups. For the 10 tests, two wordgroups were repeated once and six word groups were used only once.
1. IICertain commercial equipment, instruments, or materials are identified in thispaper to adequately specify the experimental procedure. In no case does suchidentification imply recommendation or endorsement by the National Telecommunications and Information Admini.stration, nor does it imply. that thematerial or equipment identified is necessarily the best available for thepurpose. II
2. Robert Matheson described the DM 3 in an unpublished draft, "An Instrument toMeasure the Amplitude Probability Distribution of EM Noise.
3
3. TEST RESULTSThe voice tapes were copied, edited, and sent to the U.S. Army Electronic
Proving Ground, Ft. Huachuca, Arizona, for subjective scoring by listener panels.The tapes were also scored objectively using a modification of the methodsdeveloped by Gamauf and Hartman (1977). The subjective and objective articulationscnres (AS) for 10 tests are given in Table 2.
The objective scores are plotted against the subjective scores in Figure 2.The straight line would represent perfect agreement. The correlation coefficientbetween the objective and subjective scores is .88.
The calculation of the objective score requires alining the digitized samplesof the master tape with the samples from the tapes with the noise added. In theearlier study, [Gamauf and Hartman, 1977J this was done using software. For thisstudy a newly developed hardware alinement procedure was used, greatly decreasingthe cost of obtaining the objective scores.
The APDls are given in the Appendix. The statistical parameters V(average),V(RMS) and Vd = V(RMS) - V(average) calculated from the APDls are given in Table 3.
Table 2. Voice ScoresTest No. Word Group Subjective Objective
AS AS
1 361 72.5 73.3
2 312 72.7 71.73 291 84.7 81.14 265 80.2 76.45 291 92.7 88.5
6 275 69.7 71.07 312 78.5 68. 18 305 68.2 69.8
9 214 75.5 66.7
10 265 57.7 61.0
4
90I
807060
60
100 r---------r-----,r------..---------,,.-----_
90
,......~~
en 80« 0Q)
0.~....0Q)....--
70.c::::J
en
Objective AS (%)
Figure 2. Comparison of the subjective articulation scores(AS) with the objective scores. The straightline would be perfect agreement.
5
Table 3. Statistical Noise Parqmeters
30 kHz Bandwi dth
V(RMS) V(AVG) Vd
Test # Figure # dam darn dB
1 Al -120.6 -122.2 1.6
* 2,3 A2 -lOO~6 -119.9 19.34 A3 -120.4 -121 .8 1.45 A4 -118.3 -119.7 1.46 A5 -119.9 -121 .6 1.77 A6 -117.4 -119.0 1.68 A7 -119.7 -121.5 1.89 A8 -120.9 -1'20.4 17.5
10 A9 -118. 1 -119.4 1.3Ca1i b. Al0 -121 . 0 -122.4 1.4
*The noise was the same for test 2 and 3.
4. DISCUSSION OF RESULTSTable 4 contains the statistical parameters together with the articulation
scores for easy comparison. As noted in the previous section, the corre l at icnbetween the articulation scores is .88.
It is instructive to compare the noise parameters with the subjective scoresto determine if any of these are good predictors. Several of the tests at 50 MHzallow a comparison of results because the same frequency and input signal level areused. Referring to Table 1, we would expect the following ordering (on the basisof the test condition) of the AS from best score to worst score; #4(no vehicles)#1(1 SAE), #6(6 SAE) , #8(12 SAE), #9(11 SAE & 1 SNV). The subjective articulationscores are ordered 4, 9, 1, 6, and 8, and the objective scores are ordered 4, 1,6,8, and 9. Consequently, the subjective score for test 9 appears inconsistent. Forthe five similar tests 1, 4, 6, 8, and 9, the correlations are given in Tqble 5.The four tests, 4, 1, 6, and 8 with ~espectjvely 0, 1, 6, and 12 SAE vehicles showdecreasing intelligibility (8b.2%, 72.5%, 69.7%, and 68.2%) as expected, with the
6
Tabl e 4. Tabulation for Comparison of the Noise StatisticalParameters with the Articulation Scores.
Test No. V(RMS) Vd Signal Level Subjective Objective Vehicles
dBm dB (dBm) AS AS
1 -120.6 1.6 -108 72.5 73.3 1 SAE
2 -100.6 19.3 -108 72.7 71 .7 1 SNV
3 -100.6 19.3 -98 84.7 81 . 1 II
4 -120.4 1.4 -108 80.2 76.4 NONE
5 -118.3 1.4 -101 92.7 88.5 II
6 -119.9 1.7 -108 69.7 71.0 6 SAE
7 -117.4 1.6 -101 78.5 68.1 12 SAE
8 -119.7 1.8 -108 68.2 69.8 12 SAE
9 -102.9 17.5 -108 75.5 66.7 11 SAE+SNV
10 -113 57.7 61.0 12 SAE
Table 5. Correlation Coefficients for Tests 1, 4, 6, 8, and 9 Betweenthe Statistical Noise Parameters and the Voice Scores
Subjective score
Objective score
V(RMS)
-.19
-.75
7
V(AVG)
.10
.03
.25
-.74
largest change observed between no vehicles and 1 vehicle. None of the statisticalnoise parameters appear to be a good predictor of the subjective AS although V(RMS)exhibits some correlation with the objective AS (significant at the 5% level).
The tests using a SNV, are more difficult to interpret. Previous results(Spaulding, 1976) indicate that impulsive noise is less harmful than Gaussian noiseto voice intelligibility for the same values of V(RMS). However, comparing tests 1and 2, and 8 and 9, we see that V(RMS) for the replacement of anSAE vehicle withan SNV produces a much larger V(RMS). It should be noted that for both pair~ thesubjective scores are higher when the SAE vehicle is replaced by an SNV, while theobjective scores are lower in both cases.
5. REFERENCESGamauf, K. J., and W. J. Hartman (1977), Objective measurement of voice channel
intelligibility, FAA Report No. FAA-RD-77-153, October.Spaulding, A. D. (1976), Man-made noise: The problem and recommended steps
toward solution, Office Of Telecommunications Report OT 76-85. (NTISAccess No. PB 253 745/AS).
8
APPENDIX AMPLITUDE PROBABILITY DISTRIBUTIONSFiguras Althrough A10 show the APD1s for the test conditions 1-10 and one of
the calibration runs, respectively. The sharp rise at the lower percentages inFigures A2 and A8 is typical of impulse noise. Each of these curves is normalizedto the V(RMS) for that test condition and this V(RMS) is given in the figurecaption. Note that tests 2 and 3 had the same noise condition.
9
999895
I
I
II I
,II: I I I :
i I n ! ! II !I I
I i I i I III i II
Ii I
.~ i I ii I I T I
!' !I i I I
Iii I
! iii ! II I I :' ,
I I: I
; I I!I! It
!I
i jl Ii I I
~ i! i Iii! i i I!
i I--i
I! I i I: ! :! ! T
I II:!II I I i II
jI
I": ;: I ! i
!I I Ii i II. I II I t:( .~~ I j
i ,I I I:1 1
1 1I :'1 +-+-+-
iii I: I iI
1:11 Ijj I I I I! I i-- ~-++ + ~-- Itt --+-
III I I T T ------ ~-+--
il: i
-H+f -t·!i + -t! +.'"~ III I:::
1"f--._~-
i I I iiiIi I I, it: I
I ! t- il iI I
I t-rr :11:
I I [ii I I! I !i i i: -+: : ~! I i I
I i1
j I I .. i I I
III! 'i+-- r -+
jIi I ii
I
II' !~I'I : I
! : !jl !i 1
i I I Ii iI I' i ! ! I I! i I i i I
i !I,
+-W-~I! i! CJ i
1 r'l\ ! ! I:
~i f---t- t ~+i+ -+- I II !I :' :-r f----+- .1 t-- - H-+- M-tt ~ --- I-I I ii, I i I ;1 I ; I : 1
I iii ! i-i ill 'i!1 I I --: I I,! i ! ! !
I Iii : i
~zt··!; i !
I I ! I! U- ! i 1
I II Hi: ! i I' IIII
!I
-+-! II I '-+, I I
II: I I ! I 1 !
Ii I :1 I I" ! I r 111,1 r +
I 1 !! II i! 10.i I I I
! I II !II ii:! : ! I ,;1
+i-I +- -+I
! I ~ I ! ii, I I I i :ii II
i i i
I' I I .r I: i ! I
i! I I I1 "I
I Iii! I i ! I ili! ii!, i Ii I i ! I IiiIi !
I iI I I r;
I i:1
I ! i-t-
il! II I I
-+ I
,II l !! I I IT _.-.
i I I i III I
--'-- i1- ~-1----1---: i I i Ir i
I [I Ii t- I I! Ii 1 r i
>--.-1--j! I
I Ii
i -+--- ~I---I II I
: 1 I i ! jiii
: I II I I I--t I tt-l ~+ -t--. ---- -----t
i i I III I
30
50
40
&0
-10
-20
-30
- -40.0001 .001 .01 .I .5 I 5 10 20 30 40 50 60 70 80 85 90
20......-..,--
en~a::
> 10A
OJ-0............
>0
Percent Time Ordinate ExceededUSCOMM· Ell
Figure Al. The APD's for test 1 at 50 MHz with 1 SAE vehicle.V(RMS) = -120.6 dBm.
10
99USCOMM· ElL
9895
4C
~
--II.
~
0
I~~.
r.:.
1 i I
~~
I
~~~
I I'~~~
I
I~ ~ I
.,. !!
: i I
,I~~ I
~~ II
4~
-f- - -
40
50
80
-10
-20
-40.0001.001 .01 .I .5 I 5 10 20 30 40 50 60 10 80 85 90
Percent Time Ordinate Exceeded
-30
20,.....,..,.f1)
2ct:......> toA
CD
"~>
0
Figure A2. The APD1s for tests 2 and 3 at 50 MHz with 1 supernoisy vehicle. V(RMS) = -100.6 dBm.
11
60
50
40
30
20"........,...en~a::
> 101\
co-c..........
>0
-10
-20
I-- ~.
I[
I
~ I
I
~ ~
4~~
~.
~~
~~
-30
-40.0001.001 .01 .I .5 I 5 10 20 30 40 50 60 70 80 85 90 95 98 99
Percent Time Ordinate Exceeded
Figure A3. The APD for test 4 at 50 MHz with no vehicles.V(RMS) =-120.4 dBm.
12
USCOMM· ERL
99USCOIOI· w
9895
I
I
Ii I
I I I
III I
I: I I ! II ! I Iii I I
I!I
Ii III
I! I I Iii I I
Ii I ii ! iII iii!II I III I !~ '.~
Ii--_.
r. iI
I I I I I
~"'-
I!
II
II
! ~~Iii I I I
i i ' ! i I
, II j I Jtt..' I
! I--
I I I
!I ~~I I
i
III! I J~
I II !-/'"""'
i I I I !
! I
I I I
I
II--f---- -- --f----.
I
30
50
60
40
-to
-20
- 40.0001.001 .01 .I .5 I 5 10 20 30 40 50 60 70 80 85 90
Percent Time Ordinate Exceeded
-30
20..........,......en:Ea::
> 101\
CD'"0....."
>0
Figure A4. The APD for test 5 at 29 MHz with no vehicles.V(RMS) = -118.5 dBm.
13
; I I
Ii
'. III ! I I
I i I I!!:I' iiiII
iii
I
I
!
i
!
IIi
I',II
i liI j
I
J
:1
~ I
o 1.1 Ii! II: ' 1':It-=-++--++--+-++-+1+-t~-++++-+++---+--+--+-+-+--+---+-+-+--+-~-+--- --+----+-1-t---+-+-~_t-~-+ - --+-+-- - -- -- ---~---~------1I_____-______I
I I L,\ :I! i i!I I
' I +--+-1~----+-------------+----+-----+--~I i I I:: I II!
>
I
III
I
1 I
ij
:
Ii: II
II a
i!
if: i I
:1
..
..Iii
Ii'!
USCOMM . ERL
-t98 99
I
II
5 10 20 30 40 50 60 70 80 85 90 95
Percent Time Ordinate Exceeded
- 40 ~~"""""""""""""""""""""""""""""""...I..-IIo.o.-.I.....&......\..-..L..-I.-~-'---I.---'---..L.-...,I""I",.,~'-L...J....1....I.....l.~.L..-L.--l---J..._....L..-~---J
.0001.001 .01 .I .5 I
Figure AS. The APD for test 6 at 50 MHz with 6 SAE vehicles.V(RMS) = -119.9 dBm.
14
50 t-+t--++--+-+-++t+--+-+---+-H-++-H-ir-----+--+-+.-+-+--+--lf-+-+-+--+--+--+---++++++++-if-+-+-++-+-+--+--+----+--~4_______f
j I
IIII I
I I! , Ii
"--++-+..---iI--+-ffiL : I:I ; I i
999895
!I
~-- f-~ - _~.--+-I---+---'-+---------11
90
++ +-+-i---+-+---+--'--+-----~----~t-----t
'I,, I
I I,I ji
; 'I! I
I !i! il
,!!i
i,
~ i
i II11'j 't I .I iii
80 85
i II
-+I
i
II
i
i -ti
II
IiIi
t II I
I:: III
I! !
Ii5 10 20 30 40 50 60 70
~H++++-++-+--+--I---+--+--+~-+-+---,--+---+--+t++++++++-+-+--l~t--+---+--t----+----tI
i i
Ii II 1 1
I:iII
i: !
II I
I '~I Iii II :Ii I I
I i I I i I; -: I ! i T--+--4-I---+-+I-+-+!--+-~~~I--+t-+-;,f-++++-+--+--+-+-+-+---+---t----+-~-_+_--+------t
! l~' - I iii ~,! i I! Iii ! ! i : ! I I
! I I ! I If i I ! .lI!--+----+1--+--+-1-+---+--++~-M-;i+41++--+-+aI---<f--+-1---+---+---+--+-----+-t------t
iii ;1 I I Ii: Iii! 14~~i ! i [ II I ~ Ii! I I-++'++!l+4i -++-+-+-+-I--+-----1r---+--+---+--+------+-t------t
: I!! III II:i i I Ii::t-++--++---+-t-+-+-t+--+--+-++++++++-+--+-+--+---+---+--+----+~-r.-+- -----1----- -+++-f'-+-++-t--+--+--tl--+--+- -+---+----+--~--+-----I~---I
il! i'! !i! i I : i ~__+__~-~~~+_+__1-+--+--+--t-----+---t---t------tII" ;1 i ! i I I :
1--++--++--+-+-+-+-"-1''...----W i : i ! I I I !,!l~~! i I i;:[: I I I Iii I
--+----+---+++++++-~+_+__1-+--+--+--t-----+---t---+-----I
Iii! i ::il i i : i I r. i I It-++--++--+-+--+-+t+-+-+-+-+-++++++---+--+-+--+-+ --+---+t-t-+++++-+-+-+-+-+-+--+---t--+---+--t---t------t
I I: I l Iii! I.. I I ! IiI !! ii I! Ii i IL~! : ! I ! i !ii I '.
o! i 1:1 ; i I I!!I I i 1 i j I;:j I,I! I : i I, i i [: i: I i ... 1 !! I!
H-.] ,','I I -i--i'l f-+--+-+---+A,'l+---+----+-+-t--+-+-t--1r++-+-~-+-+--+--+-+--+--t----+-+---+------t
, :'1 I iii: I ~ Ilil
- 40 '--U-~...I_L_~..L.....J"....u...&~~...I..._.L ...........__L_I~..I....-I-~..I-.--I.-.L~~j",."/",,.,,-'--'-~~ ~_~................
.0001 .001 .01 .I .5 I
-10
-30 i I
!
20,.....,,.....en~a::
> iO1\
(I)-c'-"
>
Percent Time Ordinate ExceededUSCOIIJI. f.IL
Figure A6. The APD for test 7 at 29 MHz with 12 SAE vehicles.V(RMS) = -117.4 dBm.
15
i
I I!
I : i
i
:
- ..+-.....----t--L---I
:!
:
I
j i
I I Iii I
I Jiii: i !
I
: II i TI I
Ii
I II
! !I
1iI
1 I
I
I I! -l--+-; I
I 1 !!
II T iI
! i
; : I
v~~I
:
III
Ii I
! iI
I I
I
!I
i --+
i 1-l i
1 i
I I!
ii
! I
i ;
II
I
i I
I
I
! !I
I,
I'
IIIIii
I, i I
I I 11
Ii
I!
I I IIr i
IiII:1
iiiIIIIi
i!I ~ :
I:
IlilIii!
Ii~ II!
II i
i:~~' II
III
Ii
I i
I I !I:i
i illI';
IIiiii
111\
i I
Ii
IIII
~,.....(f)
~a=......"
> 10A
CD I
~
>0
Ii : !
!I II!,
-30!I
1
~- ......I
~-
I
-40 i
.0001.001 .01 .I .5 1 5 10
i--.
-f- t·· t f
1+ - +. I tt
I !
20 30 40 50 60 70 80 85 90 95 98
.... '_'0'_-
!
99
Percent Time Ordinate ExceededUSCOMM . Ell
Figure A7. The APD for test 8 at 50 MHz with 12 SAE vehicles.V(RMS) = -119.7 dBm.
16
Ii
60~ ~ I
IIII
~~ II50 I
I!~ II!
! i
! :fj II:
40I!
!
iT I
i t
I! ~-
i
! I
I !i
:!
I ! !I
! ~ 1
I I iT
:
I I i
!--
!
I
i III
I 'I II ,
Ii
IIiI
999895
I ! i I,.. 'i i . :!; I,I! i
I ~~: I' : t! I ' i r : I I '! Ii,. I II I I --t-r I : ;!' 1-+ T +-+-t---+--+---+-----+---.J----+----I
i : I ' it ,'. L_ r;- - ' !Hj lUt------ ----I - i I ~r~ --+-i' l r ~ T -1---'--+1'-- ~-t- ~- r- - - .-ctt+· -t ~ii jl-- T I! _. __ .- I --
j .1 i ~ .+.-*'.. H.I t---- : I /,:i I' I-,r+ ~ I ,_ L ,I ~+- ;. -+~.+++-1~-+-+-+""+--+-+-+--+---+---+----+-----4I I Iii ,I j -1- I i +--+-<!f.+-1!If-+-ILl.L1-+1-+-+-1.l.-+-+---+--+---+-_-+-----+-----1
: Ii :4, ~~~~~.~~'~~,i~i+i~i~I,41~~~~-~~-~liT ! I : • i,l ! ! ~ , , I 1 I
! 1 : ,I ii, i !: i I • I! 11 iii t--+I-+-+-+---+----+--l-~
i
!-10
!
:;I
!
-20 I; ! ;,. 1:-1 'i!! ! I 'I I l I~~-H ---+-~ ri u- t ~ i ,I' t -+I-+--+--~-+----+----t---I
I i I :Ii i;1 Ii I \ , ii' +i -+--1-+-_~~_+----+-~_--II :1, I i! :: I I -r- I" j ' L!~--+-+--+-+-+-+tt ---t- ~- _..+ ' I ~ - ~ ~ - '-- f-·t--f---.
i i: I ! II li:1 ' i I I ! I,: I
~I I,': 1 iJ "',' ~- -4 -- ._- - t- -+"'1+1 U rl ~. + i t-- - ------ ---~
~: .. 1_1.. _:.!!ji , I II I, I I- 30 i : ! litTj -t;it i -;' ri.
t} I' i- T--i -r ----+- - -----+---+-------I
, i ~'l i,' ,--. -t!" : -- --1----t+;, -: -i-n· t_! ~ _~_ 4-~- 1-4~: _+ _. __ . -< I+-+ +--4----+----+---...-~__t_ ~ I ~ ill :' !I' -1- -L·.~."- -- ~~J Itljt-t~~---+----+---+--~~----I- ~-~ .~.~. .1+ -lll ) -t-tlI • ~ j;!Itil I, i 1
11 t
- 40 I i iii i I III i I I iii I i1)001 .001 .01 .I .5 I 5 10 20 30 40 50 60 70 80 85 90
20,.....,.,.....en~a::--..;
> 10
"CD'"0
......"
>0
VSCOMM· Ell
Percent Time Ordinate Exceeded
Figure AB. The APD for test 9 at 50 MHz with 11 SAE and1 super noisy vehicle. V(RMS) = -102.9 dBm.
17
t-++--++--++++++--+-~++++I+----+-+--+-+---+-4---+---4-+-~-+---+-----+----++-+--H-+-+-I--+-J~+.~--+---+__-+-__-+------+------t
It-t+-++--t--t-++t+--i-+-+++++~-+--+-+-+-+--+-+---+--+-~----++-+++-+~__I~~
II
ilt II
Ii
III;
--- t------+-----
I
I
i
I II
I
Iii
I
5 10 20 30 40 50 60 70 80 85 90
Percent Time Ordinate Exceeded
95 98 99USCOMM . ERL
Figure A9. The APD for test 10 at 147 MHz with 12 SAE vehiclesV(RMS) = -118.1 dBm.
18
ii
-- - ---_.__.~I---.-
._.• --_.- -- --
i : I i I I I I ! II ! i I ~-~4· ~~~~~I~~~~~~~-~~-~
I I :' 'i " -f.-. i· -t-"-+--~· .... ,-T-- ~-f---~ -
I ~.~- .. :tt.lrl •. ~ f ..-'I1 11 111
+I hj .Ti
Ii!'.~+-H- f..l I .- I I --r-- f--
fTf +-1,-;_, I: ; ! I~-++---+-4--+--+-++--~- I'" --·f --f--. ._-....- ' " -~r-+---+---1--+---+----t
I! 11
I ~ i _.._.. --1.- -L~- ._~ __~_+ __ ~l--t-<iH-!+I_ +---11 ~1--+---1-+-_+_-+---+--+----+------I
I 'Iii 0: : I'illl
WI -tI t:11._ iiii '._ i j: I: 4. ---t- 'r -t +- -r-~ ._....t---+t-t:--T-1
i:~+++-+-I+-1t--+-1!...--+--+---4---+-t----+---+---I
- H--r -+- - r-- --t-- -+- - . I ~ ...4--+--+---+---+----+---+----+-----1
! : 1,1 i : ~ i I :i! :;:: I iii
II
I I
20,......".....
en:Ea::--."
> 101\
CD-0.........,
>0
! : i'I !
: i
iii: i
98 999590
t
lI' f ~ I--
I : 180 85
:
5 10 20 30 40 50 60 70
I
1I
ih~+[I i ·t--+--~· + LH I.! .]. +~ ]Y-H, ' 4- -.....+- _- I' 'i I I I i
I I !:I ; l ! i
I I IiI I ! i I,.- -+ -+ -++1- --
-40 I: II II
.0001 .001 .01 .1 .5 I
-30 I 1i l
iI
I : I tli
Percent Time Ordinate ExceededUSCOflM· Ell
Figure A10. The APD for system noise through the filter, amplifier,spectrum analyzer and DM3. V(RMS) = -121.0 dBm.
19
FORM NTIA-29(4-80)
U.S. DEPARTMENT OFCOMMERCENAT'L. TELECOMMUNICATIONS AND INFORMATION ADMINISTRATION
BIBLIOGRAPHIC DATA SHEET
4. TITLE AND SUBTITLE
1. PUBLICATION NO.
NTIA Report 80-43
2. Gov't Accession No. 3. Recipient's Accession No.
5. Publication Date
Measurement of the Effect of Vehicle IgnitionNoise on Land-Mobile Voice Channels
7. AUTHOR(S)
W. J. Hartman8. PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Department of CommerceNTIA/ITS-2325 BroadwayBoulder, CO 80303
11. Sponsoring Organization Name and Address
Motor Vehicle Manufacturers Associationof the United States, Inc.Detroit, MI 48202
14. SUPPLEMENTARY NOTES
June 19806. Performing Organization Code
NTIA/ITS-29. Project/Task/Work Unit No.
910438710. Contract/Grant No.
ITS 7925-C2.5212. Type of Report and Period Covered
NTIA Report13.
15. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant bibliography or literaturesurvey, mention it here.)
Measurements of the noise intelligibility over land-mobile systemsin the presence of vehicle noise are presented. These are compared withseveral statistical noise parameters obtained from measured amplitudeprobability distributions.
16. Key Words (Alphabetical order, separated by semicolons)
Impulse noise; intelligibility; scoring; vehicle noise.
17. AVAILABILITY STATEMENT
I&l UNLIMITED.
o FOR OFFICIAL DISTRIBUTION.
18. Security Class. (This report)
Unclassified19. Security Class. (This page)
Unclassified
20. Number of pages
3221. Price:
* u.s. GOVERNMENT PRINTING OFFICE: 1980-0-679-075/478
