BSTJ 50: 10. December 1971: The Preference of Slope Overload to Granularity in the Delta Modulation of Speech. (Jayant, N.S.; Rosenberg, A.E.)

3.6 MB·English

The Preference of Slope Overload to
Granularity in the Delta Modulation of
Speech

My N. $, JAYANT ani 4. 1B. ROSTNTERG

‘Macro ne 8

A powleenes study 158 made to oztese the elie ermoyenee va
of nape stron a yr woe dlls modalted speech,
"A raven deeb ative dete moa won ain of rn
1 90 and 40 Be, and eotrlled emonate nf het hyp of newton
vor Strada is samples of 92 eae wterence. Rankivue were
(Bianca or thew soxpies im the lacie of vfeonre uot of ne
iar, each of hom asease the enon, parce, in lowrsrent
Ta ste. Revue tues tht toe speech vam eckiting fe
‘nom degradation mo ehotve,eatncutenerstana ss jetty
fhe most preferred comple Portkencome, te ruber pte dla
Inodator eekre greater evs! al east pranalorty thom the ob
Fatly oplemne ds

‘The principle of dlts amouuetion® fas em idly eseibod in the
Izerazare, Briefs, dlte moslon is x digital enowling stategy
wvlich wave a simple feedbock modhaniem to produce "Halmese™
Snproximation to sn inst sgral € Me agra othe mpl fer
Gf stn tiodslation appears i Piz. 1. The input wequenes [X) ia

‘ually bardlimitod and euitasly escmempid, The "stress se
tguence Yo generico seen te Uae esting

eam, Teal wn

Pio am eae, @

"The stepsite 4, 'sssamed to he w constant in eonvenciona! ine
dita modulation, “Adaptive” deli rinalion, 8 the othe hand
lows foe modifications of &. in geeurdiier with the changing ape
LIB vtas sean evs yonsteaL JURA, mene aan,

“ee es
a

Sale

characteristics of the inpit simul, Buch sduptution rms jn beter
‘encoding, and soveal types of adaptive deltn modulation have Been
‘Seerbed in the literature?

Tigure 2 ilusrates the mtchai of wn adaptive dele modulator
sn semonatratos how suitable inersnce wad deoteuses of ete le
feiitate better enon dig ney a lal noon a the input
ezal waveform, Buch syptainns ene helleea hy observations on
“sooend” segment of the binary ecquomes {Cy 5 this i atreted by
oguation (6) in the we

Figure 2 alk brings ut the lis neon Webvcen ta type of even
rrr dot radu, vs, “qrauular oie” and "ope veel

mem
vara wanetanion sno

norton, A given omer sample

Roxar 8)

‘en be defined to fell into the grasubir er slae-ovenion category,
{spending en vhethor the eaneosonding slap m, esse the tat
sveorm oe wo. hus, in Fig 2, thew a gramtlar enor By ct the
ammplinz inant od an “reall amar Zi, at the sapling
ft (tj. Ane inetter of deistion, we wil nate that 9 =
Big ia = 9

‘The deal oxsput 2; she lls mondolator ie aetuslly obtained by
‘iltering the staircase seqiener Tt ta the input signal hand. Tet
1X7) be the rerlt of posing (%-| Fusagl the same lowpass fer. A
reterptusly relevant measure of signtl degradation is cordingly
{find by the encoding o=mr

axe

“

As withthe quautiey in (2), ome ean sting amas of recast
tid slope overload, ol fon, inthe reer sequence fe Refering
fn Big. 2 oxco mare i eas be ceen hab pti detinoion betwee
Ie oa types oferor ie suggested. Cranalarity em be deserbed 28 2
“eignakuncoreeated” minder musotype of phevomeran. Th seb
sclera! by liemasin sig al teade eo be independent of signal
"nlite, Slope evenoad, om che otrer hand, oan be deseribod so
‘ignal-nceeleted” distortion, sino he sign nnd mgd ae led
le he spe f the signal 'This physical difference betwee. spe overland
snd granulerity ssagests » everepording pervptal dtietion and
reines the question of th relative nrousanen ves u! the two fae
ff signal dezradation in del moduli. The present papor deren
{atudy ofthe above question us mfveral to the delta modulation of
spec zal

“Eero in thi ubjoet en th frm of a pereoptual experiment”
Jn which H. Tovitt, ot al, charuotnzed the pereptbiity of slope
tied distortion ae euch, Ae mentioned earise, our paper wll sec.
to ananer the oomplementary question wf the relative pero,
A slope overload and granslaazy wea thay cecur simltaneovly in
Clotewallre ae a tony tally do,

‘The approach ‘ee ted. nce to vaay te selstive ammount slope
‘ovof and and qeabalariy inedane into eexaples of t exet tere,
nul tr waa Carte eemples on Tae basa of beth objective end per
‘optiat enteria; and tren to ntarpret these evalsations with sponitn
Zeference coche overlosd-ranulaizydiehston
3120, ine whan sree oenIONL JoLasd, aeeRsER TY

Beetion 11 eummacacs the eae: foaures of « computers
adaptive ela dla Cal wai the proven sty, Thin
winplive evade fas heen trey sleseriad and sont to provide
turcouelty epeech reproduetion at bis maser of seuetintimportaree,

Seutinn TT dohnes ihe jeerve mensane 0° epee cl he
sowed, hie Sertinn TV dekines x ahjentive rueane ope oremee
ta econ eo undeeying pecestualexperitcet,

Figur 2s selene Mba dings of helt dela medaatae
tized i the prevent dy, This enpodor Sr dened By the Basie
fquatione (1) ane (2, sd by the adepestion ule

SPs 6 6 = Coa)

chan teas PER 8)

Notine Hat a oonwentonal (iva) deta modal entreypands $0
Uespesal ease of P = 1 a war atuiy he value of P va o marble
Daramter; difarent {delta rodlated)speooh samples eneeapdal
‘iferentritably spare! valurs af 1am these tener ices
(f slogseaveroad sit granlorts

Tho crigine! epeeea stale waa Meeqnnl male tarange of “Hhave
rons su Bi" that had been band-limited to 2:1 hile, Toe eel
tmoduiaion was performed st sampling tales of 20 and 40 Ks. The
[ater recuenay provides speech reproduction thst approsches talons

we om, S

Fle $ Seca gran apt ne alate
nes sooty aia.

quality! The lower vaupling rae 604 inched to. provide a better
Ademeorsieabios of the zanoyanee properties of dataemuulaval sec,

We tll he encoding crore (2) nt define te following rsesures
of detecnvsiultor prrfermance,(Sumnations are over the sr gt
fof the speech attertncr, and a nongeen granuants error at r ~ Cimlies
feta overioad errr, ad vioe versa

{© Yh avesioud noise enoegy in Z
dy De 6;
(3) The yemulnsnose energy in 2
Ne- Zee ro
(ii) The vgna-o-neee sao

rx ‘
SMES She Bed ®

{80} ‘The sal dongrann (ovecioad-noie ato

a rx in
Sto = EM ‘

‘The periyptual evaluations of this paper are Insel we he pooled?
iiulguente a tine bsteners each of ‘um eavested speech seul
inex rine of & percept experzment Tach of Howe 81 rxpmiments
wees a couble-lizinction touraumene’ (ith 9 ifort, random,
starting inept, Mateheen cach toverament yore betwoes costending
‘time, pling to ot fies. The manly a rah math was inthe
fur wh bine referrer Sadgrt bye Benen wae the resale
fe toumann Wa eset of seston aeaeded to eae of the contesting
Speech sin th lois of ie oon in oh tourmambes, The atl
Storing rule) wis ane which, tnpeter with the double-linstion

Ee tials create
Pe er at ee
LURES

he ee acm ae
eee ht ea
S122 yar weg, sos TREMIEAT SOORVAT, pece SE TD

siren, provided 4 ful altometivg—on cmd from 0 spore
Slats the ere comprerive ting pre where ety
contending stil vl iad as ery er

Te ogre mer th thesorng lel he double
elimination srnegy wore empl rove ‘Thi wy mre 0
ecaie fy orem appliod to wat tas apparently a prbeblie
vironment th binary prfernesrernee of lstne> t's gre pair
Of eotendity winul eon well be random, expecially when the sl
fre not abou difernt ew therefor, deeded otto enphasiae
tho ace sores obtnnd inthe porapten set" weve ony Hey
ine extra ode rrkig tomatio that il i Te
sec ting and eorng ete.

Coney, the tion mubjetive petsenss vale Q wae
ssa rel of coin perl ih

Mom

oo re oo)

‘where is the ank assimed to astimuls on she bas of te soeumulated

cor a the 64 rane ofthe pereptual tet

Fiore 4 displays srmalied exluer of fv chjvetive maasarae of
dquelity SNR, SNR, und SNR. as well es tho eabjective preferenee
Fineton 9, a fanetions of the adaption parameter P. The fllowing
tlervatona en

"Tesporl sample epeernting the nina overlloivernengy
ib ot aubjecively the most pefnned sample In Fae, ab both 20 and,
4 Ils, che abjetive aud exbjrtive opin esa he eharaeteian! hy

PRE! = 1.2 ay

PHBE 15, ay
G9 The npproximaw coineidence of the SNT. and SNRy curves

inate, viet of eau (8 Roroush (0), that
Na Ne aay

{ex all eoushleen? walus of #

‘se) The velative disposi a the 3VRe, SNRs @ curves
snd of shir maim —ermeneraes thet, i spite of the preponderance
109} of averoud in the overllnoie-oneay, the pramulsity in a epest
sta sropeLsien aga

\ Sa sun sie,
N

nimails Fas strong Hnuenee on Ste sabjetive pestonene val,

‘Note that tive doable pais He subjesive proforenes sarve,
for thr Alvalle ease, This cnave casanbiqnacly ranks one of the
faperimental timsl wearing to equation (0). However, the aol
ores desing this caning show one «soul diferener between
biertinalue withthe secondae’peaeana the one immediatly peceling
Tt What i probebly ileal fea general braulening of Bre pak of
the proferenes foreion “or rstes at betwors L2 and 1

“Leble ks, forthe optinilebwrwieizationg 11) and (12), vahuce
of None given a fenetens of peal eesgy), SAIL ae Q. Noi shat
the subjeeively optimum delta rolator depags les grant
(Ne) and outer erica (Wp) than Hurabjetivelyepeinnm medulatr
Te is aun olviens bet in perception, eroad and granny ore
not weiged in pnaartinn to the respective noise energies Ny and Ne 5
SUA ne ub overine eeotnieat sc Het

‘Tame —Cranterearare oF Onmnast, AnsreyE, Pru#s Monnranin
{Bo ane My ae entra se Fsationt of sign en)

] ]

e yee | oe
SE ye) wane amor | ae | a
roan | °
ate | oar |
a cows | eo |

in ft, the prep proforma of aspire samy wees to be deter
rine very rtgly by th exten of went inf, alg dhe
Totter reorgante a vere mal ution ofthe etal ue enctas.

Tinaly, Tate Tindeos abut diintives beiwonn obletive avd
rubjecive aerate seer quali ap lo be Ton igionnt
tthe higher sampling mate of 40 kHz thus, for example he objeetvele
best deta modulstor hae s gmeatar value of rubjenive porference Q
440 klla than 98 20 kL,

We have shown that in dea nedulacion, a pose sazpleexbiitis
‘tho minimum dograction eo un objective, overall-neis-cnerzy bass
Int queers is gener, vo the perptally mee prvert rp,
“We have ab idioaed that this distinction may be low wgient
‘ghee quality deta wut than Toe i eb encoder

"The eubjesively pkinsin wlla rmonder dish grater oven
Me ami acer geanalasty Ny th the objet ely let evade. This
Tecune, oxesee sith the Tne Shut A 29 My in either wake, eget
the stmng infuses of granular noise on the pray seen
ffs apperh scale; equivalents, lessor "snayanen vale” i 1 be
sociated with sloye-overoul dstrtin* A pussible explasation of
“gr Spin POM ai ea us tne hie pce,

Wines ai ath dan pe Sado, Bina By
SST ea Me guny wall Oy a op sh
fers wom usion 8128

this observation swale be tae Iget hl yews i epee pes
feivabse by. islonor ae en “adaeive baeearovnd sie,” whe Mee
Drrsloed diction wile ky relation o orion ga hii
ti hoa to the Haener.

Trap sev scrension tet sae over “ewe arin chan
scaly i he hovel wath eution, Pauly seni tlle
hat ote evteisiog weal ayy wry 1 ho apwarh that aries oF
fuprme'estslbphone guacte, Th extrowe's Iserquality delta modula
ier ch ws no be nen spoil wpelent ur, on le other hard,
the satelite of speech. ill bey erie! wriiars and im sce
sitcation, depending mother teeta ee smart iver nar si,
ope averload may very we) Beeone 2 tore imporsant yercstusl
wate

ERE

eels Eas — veer,