CA2001071A1 - How to produce frequency/phase modulation - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A method is disclosed for producing frequency/phase modulation which is relatively inexpensive and in which the band-width is relatively narrow. According to this method information or signals are transformed into pulse periods, these pulse periods which are sent in continuous sequence or impulse times and pauses, or impulse times and pauses which are sent in continuous sequence, are transformed into unipolar or bipolar square-wave impulses with alternating characteristics, by means of an electronic relay, and square-wave impulses are transformed into sinusoidal half periods or periods, by means of filters.

Description

Z00~()71 ~ow to produce_fre ~ hs~e ~odulation Thl~ in~entlon introduces a ~ethod to produce freq~ency/phase modulatlon.
~he ~ethod~ to produce ~requenc~ modnlation (~M) known to d~te are rather expensi~e.
Within the spectru~ o~ FM oscillation there are a large nu~ber of ~lde oscillation~ abo~e and belo~ the carr~er, neces~tatl~ a verr wide band for transmiss~on. The b~nd width requlred i8 larger than double the frequency fluctuation.
The objecti~e of thls in~e~tio~ ~9 to produce a si~ple ~enerating c~rcuie for freque~c~ modulation, whlle keeping the band-width considerably smsller than that of kno~n circuits. This i8 ~chieved as per the theor~ ou~llned i~ patent clai~ 1.
In t~ e~tio~ mostly digital circuit ele~ent~ can be used, thus allowing production at a reasonable cost. Ag, ~n ~hi4 invention, l~formstion is onl~ contained in ~alf time or time of o~cillation, all harmonlc waveg can be ~uppressed wlthout causiflg 8n9 error~ ~n trsn~mission~
In the following ~ections the in~ention i8 ~urther eYplained on the b~is of the attached di~gra~8.
First, known clrcuits are described ~hich ~mongst other~ are necesscrr or productlon ~European patent appllcation 0 2B4 019).
Two practical ex~mplea of the in~entlon are de~cribed ~heresfter, st~rtln~ with a ~u~ar~ of the princtple~ under~tn8 both ~odel~.

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Informat~on i~ either pul~e~amplitude modulated and ~ub~equen~ly converted into pulse peri4ds by ~eans of the equidl~tance method, or it is i~metiately coded in pulse periods bg ~eans of tne saw-tooth ~ethod. These pulse period~, in connection with the pause3 between the pulse perlodR, are then conYerted into square-wave ~mpulse~ and ~ubsequently, by ~eans of filte~, into sinu~oidal cote slternatin~ currents. The pul~e periods and pau~es are tra~sformed by us~g co~nting l~n~s in co~nection with electronlc circuits. The pulse period is t~en eqaivalent to the duration of a ha~f period or period o the alternating current.
If the pulse period i8 ~all, the frequenc~ of the half wa~e or period of the code slternating current i~ high and~if the pulse period is large, the frequency of the half wave or period o~ the code altern~tl~g c~rrent i~ low. On the receiving end infor~ation i8 evaluated, for example, by me8~uring t~e half time or times of 09cillation. This is an e~a~ple of frequency snd phase ~odul~tio~ co~blned.
In the second ~odel, the pulse period impulse (~ee Fig. 9, PDl, PD2) ant the pause between the pul~e periods (see F~g. 9, P) -the pul~e period and the pause are, for exa~ple, equivalent t~
the dist~nce between two ~ap~ (see Fig. 6, marked tp) - sre ed into an electroni~ relsy, in which sub~equentlr bipolsr square-wave i~pul~es are created.

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The f requenc~-modulated code alternatin~ current is then produced by using ~ilters.
Fig, 2 show~ how ~o deter~ne the period o~ a pul~e -~y u~ing a counting link Z in connection with the frequency oÇ ~he ~tepping impulQe or test impul~e, which are created in oscillator Osc.
The respecti~e e~it point of the count~ng llnk give~ the ti~e.
Thi~, in connection with gates, i~ equipped ~o as to con~rol an electronic relay ~R, which ~hen protuces ~ipolar square-wave ~pulses.
The following i8 a more detailed description o~ this proces~.
The stepping impul es or te~t pul~e~ for the counting link are c~eated 1~ the os~illator ogc~ The~ ~o thro~gh gate Gl to counting link Z provided the ~tart signal iS given at B. I~ the ~odel, onl~ eYit point~ Zl and Z2 are used. These exit points are located at gates G2 and G3.
If the half pe~iod of the ~quare-w~9e impulse J ~s not to exceed the sum of test pulses up to Zl, the code~ Cod ~endg h-potential to g3, 80 that when exit point Zl is rea~hed a change in potentlal occurs at the exit point of G3, causing tbe electronic relay ER to ~top the squar~-wave impulse. If thi~ wa~ a positiYe i~pulse, the next impulse becomes negative. Tbe counting link i~
theD switched back. Gate G4 at exit point Z2 is provided for this purpo9e.

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The oscilla~or frequency can al~o be increa~ed or decrea~ed from the eoder via fA, making it po~sible with the re~pective exits to record ~ar~ing times, There i~ also a connec~ion A bet~een the eoder COD and ER to control different helghts of ~pul~e~ J.
The ~quare-wave impulses are gent via low~pa~s TP, tr8n~mitter U
and filter Fi as a sinusoidal code altern~ting current to the line. The half time or period is the same a~ that of the 9quare-~ave impulse.
The principle underlyi~g the transfor~a~ion of square~waYe impulse~ into a sinusoidal alternating c~rrent ~ illustrated in Fig. 1. If, for exa~ple, ~quare-wave l~pulse~ of 1 MH7 are band-controlled with a low-pass of 5.5 M~z, the steepne~ of the cur~e sides is con~idera~le, as sho~n in Fig. lc, In Fig. lb a low-pass of 3.5 MHz was u~ed. The steepne~s of cur~e sides i~
noticeabl~ decrea3ed. In Fig. la, ~ low-pa~ of 1.5 MH2 was us~d, which provides the receiver wit~ ~ ~ine-l~ke alternatin~
current, The times of oscillation are the ~a~e as tho~e of the 3quare-wa~e lmpul9e~, i.e. the times of o~oillstio~ can be used to measure freqUen~ies or phases.
In Fi~. 2, the ~bove principle wss applied in tranformlng square-wa~e impulse~ J into a code alternatin~ curren~ b~ using a low-pa~s TP.

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In Fig. 3 square-wave impulse~ of varying time~ of oscilla~ion ~re ~hown, called ~requenc~e~ , fl, and f 2 . The~e 3quare-~ve impulses ha~e different phase shifts or diferent freque~cie~.
It beco~e~ clear here that throu~ ~arying the time~ of oscilla~ion, rapid phase ehange~ or sutden change~ of frequency ca~ be ~ch~eved, thus prod~clng freque~c~ modul~tion.
In Fig. 4 a rapid phase change or sudden chan~e of fre~ueneg 1 achieYed in ~tages, which deerea~es the band width.
Fig, 5 show3 ~hat rapid pha~e ch~nges of fiYe degrees gield 18 de~rees each; wlth four raplt phase change steps a total phase ~hift of 40 degree~ is producedO
In Fig. 6 PAM-coded pulse~ are 9hown as Inf. The~e are trsnBformed into pulse period impulses, as ~hown in F~. 7, by using an equl4~t2nee ~eehod. The di~t~nce between PAH~impul~es (see Fig, 6, tp) is equivalent to a pulse pe~iod PD and a pause P~ a~ shown in Fig. 7. A pulse period motulatio~ can 8190 be performed by ~s~ns of th~ s~w-tooth method. Thi~ method i9 illu~trated in Fig, 8 and Fig. 9. Th~ pulse periot~ ~re square-wave pulse~ PDl, and PD2. Fur~her know~ a~e th~
sr~metrleal PDM and the bipola~ PDM, (~ee also "Modulatlo~sverfahren" - Modulatl~g Method - a book by Stadler, 1983).

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In F~g. lO a ~odel according to thi~ invention is shown. Pul~e~
are creaced in pulse period modulator PD~, e.g. in Fig. 7 or Flg.
~, and sent to gate Gl via G5. At the other inpu~ point of gate Gl are the te~t pulses JM, e.g. a frequency of 1000 k~z. As long as there is a PD-pul~e a~ ~1 t~e test pulges Jm become effectlve a~ the exit point~. The test pulses reach the coun~ing link Z, which is controlled by the~e i~pulse8. through the potenti~l-rever~e gate G~. The number of exit points on the counti~g link corresponds to the distance between two PAM pul~eq, called tp in Fi8. 6. A gl~en tap frequency i8 10 kHz, wi~h the counting lin~ ha~in8 1000 exit poin~s. The frequency fluctuation i9 de~ermined by the hi~he~t and lowe~t pulse a~pl~ tude of inform~tion Inf, called gw and kw in Fig. 6. The e~it po1~t~ A
of counti~g link Z lead to gate~ G3, and ~he eY~t polnts of the ~ate~ to gates G4. The PD-impul~e that locks ~ate G4 eo~e~ trom the other lnput point of gate G4. The outpu~ poten~ial to ~4 via G3 can onl~ then become efective when the PD-i~pul3e ls gone.
~R now receive~ a change-in-potential signal f or the next 3quare-w~ve imp~lse v~a G4. The start of a square-wave i~pul~e i~ market by a ~D~pulse. The neYt square-waYe impulse 18 ~arked by pau~e P (see Fig. 7, P). ER ~end~ a potential to gate 5 through P, thereby allowin~ test pul~es JM to pass ~ate G1 again.

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The counting link Z is now switche~ up to ~ate G6. When the next PD-pulse comes through G6 ~ecomes e~fective and the counting link is swi~ched bsck to its s~arting position v~a K. Square-wave impulse~ ~J,~he ~i~e of the hal~ periods as well a~ the PD-pulses and the pauses P, are then at the output point o ER~ In the filter Fi the square-wave impulse tura into ~mnusoldal half waves f~o, and information i8 thus frequency modulated. The half period~ of the intefli~ence signal modulation requencies lie then between hal~-p~riod tlme~ on the counting link, ~arked l/kw and 1Jgw . In Fig, 11, for e~ample, 1/kw = 15 kHz, w~th a center frequency of 10 kHz, and in Fig. 12 l/~w = 7.5 kHz. In ~hi~ example the pulse periods can vary by half. Thl3 is a matter o dimensioning of pulse period ~odulation circuits. In Fi8. 11 the h~lf wave~ of the lntervals have a ~inimu~ ~requency of 7.5 kHz, and, in Fig. 12, a ~axi~um ~re9uency o 15 kHz. The ~mplttudes of the half wa~es remain const~nt. At the ~eceivin~
end i~for~8tion is evaluated by measuring the half p8riod t~mes.
Synchroniza~ion i9 not neces~ary, as the zero pas~sges of a period when being coted also code the taps by mean~ of a PAM.
Therefore, only ~he posieive half wa~es have to be tran3formed lnto P~M-p~lses. The PAM-pulses ehen lag by one period at the receiving end.

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It is possible to avoid ~he redundancy o~ pauses, a~ per Fig. lO, by storing the PAM-pulses, and by calling ~he next PA~-pul~e after each PD-codin~. In this CaBe~ however, synchroniza~ion at the receiving end is required, ~hen using the PAM on the t~ansmi~ing end, the tap frequency would ~eed to be synchronized from time ~o eime. Fig. 13 shows the basic circuit dia8ram of such a circuit at the tran~mittin~ end. The PAM-pulses are stored in Sp. The next imp~l~e i8 called by ER via AR1 while the subsequent i~pulse is already ~tored as a PDM-i~pulse in Spl.
This is now used to control ~he counting link Z by means of control St and ~et to a specific exit point. ER switches back ~he counting link to its startin8 position via R. The control impul989 Jm also come from control St. When a PDM-impul~e is called the storage element Sp also sends a PA~-impu1se to the pulse interval modulator where ît is s~ared in for~ of PDM impulse until storage element Spl is clear. For expediency's s~ke, two Spl stora~e elements should be ueed which are al~ernatively switched to the modulator unit a~ter every call by ER, At the en.d of a PDM-impulse ~n impulse-end signal is sent to E~ via counting lînk Z, G1, G2. The ~quare-wave impulse PD, generaeed by ER, is reversed on~o the next one, while the countin~ k is switched back via R and the next PDM-impulse is belng called via AR.

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.~e ~quare-wave i~pulses RJ are retransmitted th~ou~h a filter.
At the exit point of ~he filter half wave~ a~e produced with ~he half period ~n~e~al.s of the PDM-impulses, as shown in Fi~. 14.
In ~ig. 15 the PD-pul~e~ and~if applicable~the intervals ac in Fig, 7 and Fig. ~, dlrectly control the elec~ronic relay ER.
Polsrity ls reversed after each square-wave i~pul~e. The relay ER can also be rontrolled, a~ sho~n in Flg. 15, by a continuou~
flow of PD-pulses which is achie~ed through stor~ge, as illustrated in Fi8. 13. Howe~er, it is nece~sary to re~er~e polarity after each impulse. In Fi~. 15 the start of ever~
PD-pulse is ~arket through PDS o~ly when a con~inuous t~anom$s~10n of PD-pul~es ls required~ ID the case of transmission pulqe~pause the marki~8 Of beginning and end o~ a p~lse i~ a gi~en.
If during transmission no ~lrect current is de~ired every pulse must be coded w~ th a po~itive half wave and a negati~e half wa~e.
~his can be achie~ed, or ex~mple, through ~torsge in a slidi~g impulse-storin~ device. In e~aluating this a wired ~isection of t~e o~erlapping exit poin~ or a bisection by m~ans of a computer en8ue6. A bi~ection into two hal~ pulses can also be achieved by means of the cymme~rical PDM.
The PDM~i~puloes. as in Fi~. 9, can also be directly switchet through a filter Fi, as in Fig. 15.

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~n order to keep the ba~d wid~h reason~blg s~all it is practical to feed information into the ~aw-tooth volt~ge in such a way that the di~erence in length or width o~ ~he impulse~ re~ainQ
rea~onably ~mall.
The PP-impulses, as in Fig. 7, can also ~e directly switchet to the F.R ci~cuit element, After each impulse, automatically reversed polarity or ~o potential ~ust b~ ~witched to the sQuare-wa~e impulse~, ~n tha~ caae the squ~re-wave i~pulses are single-polarity ones. In order to decrea~e the band width ~hen applying the oquidlq~ance methot wieh direct control ~f the ~
circult element it iS neces~ary, when producin~ PAM-impulseq, to u~e either 2 hi8her dlrect-current bias voltage (~i~h unlpolar PAM) or to dimension ~he circ~i~ for producing the PDMo Fig. 16 illustrates an evaluation of the P~-, PPM-~ and PF~-impulses coded with hal~-period inte~al~, which 1~ achie~ed by ~eans of a ~aw-tooth valtage. At the start of a half waYe, and also during a zero passage, the generator of the saw-tooth voltaYe i5 activated. After the half wave, d~ring the next zero pas~age, the s8w-~ooth voltage i8 te~porarily ~witehed to a conden~ar by usi~ a field ~requency transistor and stored in the condenser.
The hAlf-per~od ti~e T¦2 is then equiYalent to the ~oltage coeffioient T/2 or analogous to the si~e of the voltage coefficient.

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Aha~-per-od time of 1 corresponds to the voltage coe~icient ul, a ~alf-periôd time of 2 to ~he voltage coef~lcient u2, e~c~ If at the tr~n~mitting end a ~oice iq pulse-ampli~ude ~odulated with 8 kHz, ~he ~ame frequenc~ mu~t be used at the receiving end to tap the voltage ul, u2, and u3, and be tran~formed into voice frequencg. In the ca8e of time ~ultiplex tapping of ~eversl channels the tored values ul> u2, u3, .... ~ùQt be redigtribueed wi~h the same frequency that wa~ used durin~ ~he time multiplex tapping. The ori~inal information can be produ~ed, for example, b~ converting the evaluatet code ul, u2, ..., ~fter channel allocation, into ~tepped form and then sendlng this stepped signal through a low-pa~s, Such transPormations are Plready known and will therefore not be discu~sed in further detail.
The PP~-impul3es can be decoded in ~he same wsy as the PDM-impul8es in Fi8. ~6. This i~ illustrated in Fi8. 17. The dlstsnce T/2 between pul~es is again tr~sformed i~o PA~-pul~e~
by means of the saw-tooth method ~nd thon ~tored. The inte~val T/2 i~ then equi~81ent to the voltage ul, etc.
By using ehi~ principle it i~ also possible to combine aeveral eh8nnels on one trans~ ion pa~h, a~ shown in Fig. 18. The ~ultiplex element Mu co~bi~e~ channels 1 to n in pulse-a~plitude manner, whiCh i8 already ~nown.

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The~e PAM-sa~ples ere ~tored in storage ele~ent Sp, recalled by PDM, as de.~cribed above, and switched to the counting link via a mod~ator unit to which ~he control impulses Jm are connected.
The other circuit processes are the sa~e 88 de~cr~bed, fo~
egample, i~ Fig. 13. ~fter the pulse-period ~odulator PD~, impulses can ~ be further processed, as ~hown in Fi~. 15. At the recei~ing end synchron~7ation ant redistributlon happen in ~ceordance wit~ the tapping frequenc~ u~ed by ~he multiplex ele~ent.
In Fig. 19 another possibilîny for multiple exploitation of a eurrent p~th i8 illustrated. In order to be able to separate the code alte~nating current~ ~y frequenc~, ~ontrol impulgeg are u4ed wh~re the distances in the frequency r~nges o ~he code alternatln~ currents are ~uch tha~ a faultless e~aluation becomes possible, e.g. by ~eans of a fll~er at t4e receiving ~tation. In Fig. 19, Zl is one transformer with co~trol impul~es ~1, and Z2 the o~her transormer or countin~ link with control i~pulses ~m2.
Fig. 20 illustrate~ the frequency ranges of the two channels, with T/2I and T/2II bein~ the lowest frequencies. The an~ulsr fluctuation f2 brings ~ou closer to the requehcy range of channel T/2I, In the diagram a dl~nce Ab is also ~hown. This di~tance can ~e chos¢n ~o aq to allow the use of non-expensive il~ers .

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Another cir~uit, illustrating multiple exploitation of current path~, is shown in Fig. 21. Information In~ 1 ls, for exsmple, sent to a pul~e-period ~od~lator P~M, which funct~on~ aceording to the ~aw-tooth method, Furthermore, there ~s also Q ~orage elem~nt in PDM which ~tores PAN-impul~es un~ he~ ~re called.
The PDM impul~es are then pa~ed on to the electronic relag ER.
The i~pulses are called o~e after ano~her. In relay ER
alternating sign~l are being switched, i.e. depending on whether the square-wave i~pulse~ are supposed to be unt polar or bipolar ~he electronic relay ~witches p~tential/no pot~ntial or ~ and - potential. From the relay ER the ~quare-wave impulses are ~ent to ~ filter which i~ dimens~oned ~o as to p~ot~ce an output of ~lnusoidal alternsting current. Infor~ation Inf2 i8 sent to a PDM modulator ~h~ch con~erts PAM-impul~e~ ~n~o other l~pul~es, thus preventing the respectiYe lengths of In 1 and In2 from nterlocking, as ~hown in Fig. 20. The alternating current~
coming from ~e filter~ Fi ~hen h~ve frequency bands that ~ill not allow ang interlocking when the currents are coupled by meang of the adder Ad and sent out on a joint ourrent path. The relg~ E~, in par~icul~r, can reinforce the s~uare-wa~e i~pulses.
~n Fig. 22 the Y~me installation is shown again but ~ithou~ rel~y ~,R. The PDM square-wa~e imp-~lsee are in this case switched directl~ to the filters Fi.

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Fig, 23 ~hows how PDM-i~pulses are produced ~y usin~ the ~qu~dlsSance method. ~e will not tl~cuss the circuit in greater detail. (An illustration o~ this circuit can be ound in Stadler' 8 book ~Mod~latlon~verfahren" - Modulati~g Method -, page 143, third edition). The PAM-impulse~ are ~tored and recalled at the end of each PDM~ pul8e. In Fig. 24a 8uch a c~lterion 13 produced by putting ~he saw-tooth voltage at one input point of a gate and a voltage of approx~mately O volt ~t the other. I~ the cage of coincidence, the gtorage element will cause the next PAM-impulge to be sent. In Fig. 24b the same applies as in Fig. 24a. It ifi also pos~lble to produee sqUAre-wave l~pul~es fro~ the impulses ahown in Fig. 24a a~d Fig.
2~b.
In the examples discussed so far, analogous codes were illustrated ~hich would be used e.g. in telep~ony, data transmission, telemetry, etc. In the follo~ing seCtions a few exa~ples of appllcations for tele~is~Q will be di~cu~sed. Fig.
~5 shows the coding of colour tele~i~ion signals. The value~ of the image spots B(Y) ant ~he colour-tifference si~nal9 sre defined in the dur~tion o~ a hal~ period T/2, with the size o~ the ~al~ period~s amplituteg re~ainin8 constant. The ln~ividual signal~ are a8ain 8rran~ed in ~eries, y, r, y, bl, y, T~S, as per F~g. 25.

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Trang~ ion occurs ac a tappln~ frequ~nc~ ~f the Y-~lgnal ~lth 6 .M~z. Durin~ ~ultipl~x tApplng o~ lgn~l~, lncludl~g r, bl, ~nd T+S, a tapping frequenc~ of 12 MHz i~ r~qulred.
In Fig, 26 the ~ codin~ as in Flg. 25 i~ used, ~lth only the sound and other signals ~s belng coded b~ ~e~n~ of ~ het~rod~ne a~plitude code. Thls 1~ ~ binary cod~ vlth an amplitu~e rang~
from high to low. The v~l~es of the Y- and r+bl-~ignal~ ~r~
determined through ~al~-period times. I~ ~ynchr~nlsm wi~h the PDH-i~pulse an amplitudc val~e i8 s~nt to the rela~ ~R, a~ sho~n in Fi8. 13, where subseque~tly 8 squ~re-wav¢ l~pulse of hi8h or lo~ voltage 1~ protuced, The a~plltute code elemen~ ca~ ~e Bs~1gned ~o s~eral channel~, e.g. sound~ ~tereo, etc. In Fig.
27 the four h~lf-wave eleDents are as~lgned to four 4iffer~nS

ch~nnel~.
~g. 28 and Fig. 29 show a method to code colour signals for the colour~ r~d and blue. During coding the character~stic value~ of colour are scanned with a prede~ermined frequ~ncy and then each modulated upon carriers which are ln phase quadrature. The carriers have at least twice the scan frequency.
~hey are totallet up. The total alternating curr~nt, through pha~e shift vi8-a-vis a reference ~lternatlng current, conta~n9 the position of the ~olour vector w$thin the coloux speCtru~.
This phase shift 1~ defined by th0 t~me of oscillation or remaini~g time of oscillation, marked dw in Fig. ~9a, ~is-a-vis the rsference alternating current. ~n t~e case of a two-fold carrier frequency up to half the number o~ taps per lin~, and in the cas~ of a three-~old carrier freq~ency ~ 3 o the tap~
p~r l~ ne need to be stored . Durinq tran~mis~$on th~ values Of the phase Shift ar~ included in the h~lr tl~- or ti~e of os~-illation of an alternating current. ln order to malntain ~reedom of ., - - :

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direct current in the case of transmis~ion via cable, a period can be provided during which the positive h~lf wave and the negative half wave ~how the same valua. ~n the example, the carriers ha~ a three-fold scan ~requency.

In ~ig. 28~ the Rcanning i~pul~es P1, P2, P3 ,,. sre illu~trsted b~ ~ean~ of the colour difference sig~l B-Y. Th~e lmpulses are being exp~ntet in steppet for~ - marked 1A the diagra~ wlth a ~oeted llno.
Thl~ C8n be achievet b~ usin~ a condensQr storage elemeDt ~ith a J e e, ~ V ~ , a ~ n l n ~ p p l l c a t ~ o -~ o o eh~ d are alresd~ kno~n, ~ee for exa~ple pat~nt ~peciflcation DE
1101S39. In Fi8. 28b the taps Pl, P2, P3 ... and the pertinen~
st~pped ~gn~l~ aro illu~trAted b~ ~eans of tho colour-dlff~rence slgnal ~-~. In Fig. 28c ~nd Flg. 28t, carricr~ whlch are in ~haae quatraturc vlth stepped ~nd ~odul~ted upon ~lg~als are ahovn. If the carrl~ra from Plg. 28c and Pl~. 28d are ~dted, a ~um carrler i~ obtained, a~ ~hown in FSg, 28e, vith a~plltude deter~inlng the size of the colour Yector. Saturat~on and phase shl~tlng vls-J-vl~ an e~it ph~e detor~lne th~ chro~a withln the colour spoctruo. This la alread~ ~no~n ro~ tho NTSC- an~
P~L~ cem~ and ~lll thereforc not be ti3cussed further~
In Fig. 28f the e~t os reforence phAge V8 i8 shown. Ph~se shiftin8 remAins pre~ent during the three intervals of carri~r Su. It 18 not po~siblo to mea~ure the halt_perlod tlm~ at tho time of a ph~se ~hift. For this reason at 1~3t threc per~od~
ha~e be~n alloYot betweon pha~e shlfts.

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1 ~ / . . .

As lllustrated in Fig, 28g, a code hal~ pe~oA ~ongi~ts of two con~tant periods ~P and the ac~ual code phas~ shi~ Ph, which, at a pha~e shift of 359 degrees al~ost consti~u~eS one period. The indiYidual ~tepR involved in tr~ngmi~sion of phage shif~lng to tl~es of 08cill~10n are shown in ~ig. 29. Also oho~n are three colour ~pectra with pha~e shiftA of 60, 120, and 140 te~rees.
The start of the mes~uring range i8 marked PhO in Fig. 28g and Fig. 29a, 29b, and 29c, In Fig. 29d the "burst" ~ould ha~e ph~e leYel of zero degrees, except that ns "burgt" is nece~sar~
as t~ansmi~sl4n is determined by means of the absolute time o~
o~clllation value. It i9 practical to code for every llne the be8in~ing of the code ele~ents 8rr~ged in ~eries. The halr-period ti~e, i.e. the impulse which, for eYample in Pig. 21l cont~ols relay ~R, sta~ts at Be in F~g. 28f, and la~t~ for the two period~ plus the size of the phase shift Ph. In Fig. 29a, in the case of a phsse shift of 60 degrees a phase shift of 300 de~ree~ easured. The total ~mpulse is eguivalent to ~he two periods plu8 the length of 300 degrees. T~i~ impulse is amplif ied b~ ~ean~ of a rel~y ~R snd then tra~sormed ~n~o a 9inu80~ dal code alternatlng current ~ia a filter as described on Qe~eral occa~ions above. The duratio~ of ~alf-period time~ in tele~i~ion line becomes shorter thsn the lnterval6 of the sum of stepped ~ignals of the colour-dlffe~ence si&nals, . ~. . . ............................................. .
- - , . . ..

. ~

`-` 2~ 7~

18/...

For this reason it is al~o necessa{y to Measure ~he sum of half-perlod time~ and, if ~equired, to introduce a filler h~lf p~riod. Fhr practical rea~ons, three periodB of the reference alternating current ~ould be a~si~ned to thi~
filler period. The alternating currents ~hown in F~8. 2~a, 29b and 29c are total alter~ating cu~rents Su. In Fig. 29b the colour angle is 120 degrees, wlth 240 degrees being measuret, while in Fig. 29c the colour angle is 260 de~ree8, with 120 degrees being mea~ured, The measured time of oscillation is added to ~he two con~tant periot~ ~P. In these example9 respective satu~a~ion 5~ i8 1002 ~nd 70%. The rel~tionship bet~een saturstion and amplitudes is the same a~ in the PAL-gystem. Fig.
~9d shows a ph~se reference alternating current. The time of oscillation o~ one period of the total alternatlng current has a phase angle of 360 degrees. It i~ possible ~o achieve greater precision by asæl~ing 180 degrees to one periot, ~y using an additional m~r~er. If a phase shift up to 180 degrees occur~, phase shift exceeding 180 degree~ is measuret, as ill~strated in Fig. 2ga and Fig. 2gb. In this case, only the ph~se shift of the positive hal~ period needs to be measured. As with ~alf perlod8 only the time of oscillation ~ needed for the coding of the ~lze of lm~ge spot~, an amplitude code ca~ be u~ed ~o define the angle as exceeding 180 de8ree~.

' 200~071 19/ . . .

During transmission, dou~le the value of the angle can be ~ransmitted. As per Fig. 29a the size of the angle dw can be allowed ~o double. At the recel~ing station the amplitude code needs ~o be ev~luated and the additio~al ~80 degree angle taken into consideration. Trangmission of colour coding and lmage ~pot coding can be done paralleled, ~imilar to the example sho~n in Fig. 20, o~ in ceries, as illu~trg~ed in Fi8. 30 and Fi~. 31. In these examples, image spots are sc~nned twice as fast as colour signals. ~ ~he objective is to ha~e a code alter~ting current with a continuous flo~ of poQitive and ne~ti~e half period~, there i8 no Qy~chroni~m between tapping and coding. More or less sizeable ~torage i8 therefore ~equired at both the transmltting and the receiving end. The sa~e scan fre~uency that was u~ed at the transmittin~ end muAt ~e u~ed for the alloc~ion of these image .~pot~ and colour signals at the recei~i~g end. The size of the colour vector, marked VS in Fi8.
29~, is coded by mea~s o the amplitude size, which is stored in the ~me wa~ as the tlme of o~c~ tion. A possible ~oDfigura~ion ls illustrated in Fig. 30. The re~pective sc~nning Y~l~e~ of image ant type of colour determine the required frequency. If on one llne 83Z image SpO~8 need t~ be sca~ned, with e~ery image spot requiring one half period, a total of 416 periods are required fo~ the3e image spot~.

.~ ' - ~ ~ ' ' -;~00~;)7~

2~/...

In the case of colour coding, one h~li period i8 allocated to e~ery two image -~pot~, i.e. 213 period~ to one line. For example, ~ ~ime of 5~a is allocated to these 629 periods. This defines ~he minimu~ frequency of ~he code al~erna~lng current.
The ~ame frequency ls allocaned to the blanking interval of 12~s.
Sin~e the value of code hal~ periods is alwayg ~maller than the calculated one, it i~ necessary to u~e filler half period~ which show up the longeot times of oscilla~ion. A different code can be used for thexe, of course. The a~plitude size of the ima8e spot half p~riod6 i~ always the same, while in the ca~e o~ colo~r half pe~iod~ the amplitude Bize i~ u~ed ~o code the colo~r vecto~, ~nd thus the deg~ee of ~aturation. The lar~est amplitude size of the colour hal~ periods, which are also u~ed for the i~sge ~pot hal~ period8, can al~o be used to code the filler half periodc.
The amplitude size of the colour or ~aturation ~ector ~an be ~tored by means of a condenses ~hich is switched to t~e code alternatlng c~rrent Su via a diode. The ima8e ~pot half perlods B(Y) can fnr~her be overlaid with a b~nary or a duo-binary amplitude code which ~ould then ~e used to di8ital1y code voice and other signal~, as alre~d~ de~cribed ln reference to Fi~. 26 and Fig. 27.

:: :

Z0~1~71 21/...

In Flg. 31 a binary codin~ for a pha~e angle of the chroma exceeding 180 degree~ h~s been allo~ed per lmage spot ha~f perlod. In Fi~. 29a, ~or ex~mple. it is ill~ tra~ed tha~
the re~aining hal~ perlod dw to be mea~ured is positive. thus el~ min~ting the need to mea~ure the ~ega~ive half wave. In this e~aDple, 180 degrees is defined as codi~g B~18~. During trans~i~sion, the v~lue of dw double~, thu~ incre~sin~ precision.
The other lm~ge spot half period B+T/S ~c overlaid with ~ binary or duo-binary a~plitude code, which ls then u~ed . or digit~llzet voice and other co~trol ~ignals.
The half per~od F contains the chroma in the half-period time and corres~ondi~gl~, the co}our or satur8tion in the aoplitude ~lze.
Fi8. 32 illustrate~ the principle of coupling hal~ perlod~ with the ~m~litude cote. A~ eleotronic relay ER 4ends o~t ~quare-~a~e impulses ~J. $he time of o~cillation of ~hese square-w~Ye inpulse~ is marked Yia ~h. There are storage ele~ent8 ln the ~ila OrH in which the image spot taps, possibly haYln~ beeQ
tras~formed into half-period ti~e~, are ~tored. There 1~ sl~o a 9torage element to store the oolour angle KP+P~. From ile OrA the a~plitude~ of the square-waYe impulse~ are sent to the electronic rela~ ER in synchronism with the half-perlod time8.
The analo30u9 ampli~ude size of the colour vector is recallet f rom stora8H vla FA.

- - . - . . ~

- . , - , ~ -z~o~

22J....

The digitalized sou~d amplitude~ and other si~nal amplitudes are reca}lçd from storage ~i~ T~S and subsequentlg sent to electronic relay ER, for example in ehe order sho~n ~n Fi~. 3~. Fi8-illu8trates an electronic relay with se~eral amplitude step~.The ~qusre-wave impul~e~ wlth their corre~ponding tlmes af oscilla~ion and ampli~ude steps are at the exit point of ~R.
~he~ are then con~erted into a ~lnusoidal alternati~g current in filter Fi.
It i8 also po~ible to ~easure the pha~e an~le directly. Zero pa~sages st~rting at BE (~ee FiX~ 28g) ha~e to be counted rom the total alternating current in order to make it pos~ible to e~t~blish the zero pa~sage M in Fig. 29b. Mensure~ent i8 take~
b~tween thi~ point and ~h~. In Fig, 28g Ph could be di~tribut~d o~o 90 degrees of the pba8e shift. The thr¢e remainin8 90 de~res angles would have to ~e coded 180 degrees, 91mllsr to those shown in ig. 31.
The code ~lternating current~ in Fig. 30 ~nt Flg. 31 are motul~ted upon ehe ~ending alternating current and then transmitted. The recei~er is switehed as ~hown in Fig. 33. The input signals E are ~ent to de~otul~tor DM vla tuning circuit/~mplifier A+V, co~bined oscillator detector Mi and intermetia~e frequency amplif ler ZF.

~:

' ' .:
:

- Z~0~(~71 23~...

As, ~or example, sho~n in Fig. 33, ~he demodulated code alternating curren~ i~ sent to decoder D~. When code h~l~ periot~
are ~rran8ed in series, the ima8e value~ and colour val~es (see Fig. 30 and Fig. 31) ha~e ~o be distributed in accordance with the image 8pO~ si~nal tap~ a~t the colour-differe~ce ~ignal taps.
It is therefore practical dur~n~ the suppres~ion period ~o ~end an alternati~g ourrent with the scan frequency which will ~nchroni7e the alternatin~ ~urrent that func~ions a.Q di~tributor in the reeeiYer. The amplitude~ of this ~ynchronizlng alte~n~ting current of the suppres~o~ period c~n al~o be coded ln 8 binary or duo-bin8r~ a8h~on. The i~age ~pot ~alues can be e~lu~tet a~ shown in Fig, 16, for e~ample. T~e evaluation of the colour code eleme~ta, along ~ith th~ ~al~-period tlmes and amplltude ~ize, w~ich, if necessary, i9 tran~formed into one length - as shown in a ~lmllgr wa~ in FigA ~4a - la be~t done by computatlon. The sound (~tereo) aad other signal~ which are PCH-co~ed can be demodulated b~ using k30wn ~ct~ods.
Fig. 34 shows l~ge ~pot taps BAb and colour-tifference ~ al ta p~ FAb. Fi~. 34 al~o il~uYtrates how ~o allocg~e these to the code alternating current Cod in the ca~e o trsnsmi~sion in series (~ee Fi&- 30) .: , : .. ~ ' :

. ~
- . . . . - . .

Claims (8)

1) A method to produce frequency/phase modulation by using elements to perform the following functions:
- transforming information or signals into pulse periods;
- transforming these pulse periods which are sent in continuous sequence or impulse times and pauses, or impulse times and pauses which are sent in continuous sequence, into unipolar or bipolar square-wave impulses with alternating characteristics, by means of an electronic relay;
- transforming square-wave impulses into sinusoidal half periods or periods, by means of filters.

2) A method for the multiple exploitation of current paths based on the principle of frequency/phase modulation, involving the following functions:
- scanning of information of one channel or a group of channels with a predetermined frequency, and scanning of information of another channel or a group of other channels with a different frequency;

25/...

- sending PAM-impulses to permanent modulators - transforming permanent impulses and, if applicable, pauses, into unipolar or bipolar square-wave impulses with alternating characteristics, by means of electronic relay, to which the permanent impulses or the permanent impulses and pauses are sent directly or indirectly in continuous sequence;
- transforming the square-wave impulses into sinusoidal half periods or periods, by means of filters, The code alternating currents of the different channels or groups of channels are sent onto a joint current path via an adder.

3) A method for the multiple exploitation of current paths based on the principle of frequency/phase modulation, involving the following functions:
- that information from one channel or a group of channels on the one hand and information from a different channel or a different group of channels on the other hand is scanned and stored with the same frequency;
- that the two different channels or different groups of channels receive counting links through certain control pulses with a certain frequency, thus preventing the frequencies of the scanned impulse times from interfering 26/...
with each other during further processing.
- transforming permanent impulses and, if applicable, pauses.
into unipolar or bipolar square-ware impulses with alternating characteristics, by means of electronic relays, to which the permanent impulses or the permanent impulses and pauses are sent directly or indirectly in continuous sequence;
- transforming the square-wave impulses into sinusoidal half periods or periods, by means of filters.
The code alternating currents of the different channels or groups of channels are sent onto a joint current path via an adder.

4) A method to evaluate distances, for example, between either pulses or half times or times of oscillation, In this method a saw-tooth voltage is initiated at the beginning of the distance mark or at the zero passage of a half period. At the end of the distance mark or the second zero passage of a half period the saw-tooth voltage is induced by means which will measure this voltage, or certain means are provided (e.g. FET) to store this voltage in a condenser.

5) A method to transmit analogous or digital pulse-amplitude modulated information of two channels.

27/...

In this method the respective pulses of both channels are transformed into a stepped signal (see Fig. 28a and Fig.
28b). Two carriers which are in phase quadrature are given a certain frequency in order to form a whole multiple vis-a-vis the scan frequency. At a predetermined number of periods the stepped signal is modulated upon its allocated carrier. The carrier alternating currents are added while the phase shift of the total alternating current vis-a-vis a reference alternating current (see Fig. 28f) is measured, and while one or more periods of the reference alternating current are added up to a total time of oscillation, The amplitude of the total alternating current is superimposed onto the code half period with the total time of oscillation.

6) A method along the lines of Method 4) above, Method 6) is used for the transmission of characteristic values of colour in television.

7) A method along the lines of Methods 1) to 5) above. In Method 7) image spots or the Y-signals are frequency phase modulated and transmitted in series or paralleled with the frequency modulated and phase modulated colour signals.

8. A method for the coding of information of two channels for purposes of combining them into one channel characterized by the fact that only one alternating current is provided for this in such a way that the PAM-modulated or PAM/PCM-coded information is converted into staircase signals of a pre-determined frequency and are modulated upon one carrier of the same frequency that are in phase quadrature with one another, the frequency of the carriers being an integral multiple of the tapped frequencies and both carrier alternating currents being added together.