DE3226382A1 - Method for transmitting picture and sound signals in television - Google Patents

Abstract

To avoid the bandwidth becoming two wide and to save a diplexer in the transmitter, all signals, even the sound signals, are transmitted with an alternating current of one frequency. As well, the expenditure for coding the hue and colour saturation signals, is reduced by a differentiated marking of the hue such as, for example, quadrant and/or angle transmission.

Description

Process for the transmission of picture and sound signals in television.

The present invention is concerned with the transmission of image and audio signals on an analogue and digital basis for television.

In the case of the relevant methods known today, the image signals are transmitted through direct modulation of the voltage value of a picture element on the alternating current transmission. This also creates low frequencies down to direct current, which is disadvantageous affects the power supply and the modulation amplifier. The hue and color saturation signals are a carrier, which is arranged in a pure frequency gap of the luminance signal is fed in quadrature modulation, the phase distortions occurring at the receiver result in a falsification of the color, in particular. The PAL system works here probably a remedy, but this system entails considerable costs. In the USA it will be also called with Pay Additional Luxory The same also applies to the SECAM system. ###### The sound is frequency-modulated and transmitted with its own carrier, which again requires a wider frequency band and also requires a diplexer at the transmitter power.

The object of the present invention is now a personal transmission system to get by with less bandwidth and the shortcomings listed above of the existing systems eliminated. This is given by that given in claim 1 Teaching achieved.

First, the two transmission codes will be explained. A binary code is shown in FIGS. The half-wave or the period of a We ¢ hvaA selstromes provided with the characteristic states of large amplitude value and small amplitude value, respectively, in the immediate sequence of positive and negative half-waves. Periods to be ended. The small amplitude value is at most half as large as the large one. In FIG. 1, the characteristic states 1a and Ic are equal to the large amplitude value and the characteristic states 1b and Id are equal to the small amplitude value. A corresponding 5-digit code word OW is shown in FIG. The characteristic states of the period are recorded in FIG. 3, namely 3a, c large amplitude value and 3b, d small amplitude value. 4 shows the 4 combinations of a 2-digit code word with a frequency f1. In FIG. 5, a 2-digit code word is marked with a frequency by means of two channels K1 and E2.

You can also combine with several frequencies.

The analog transmission code used is shown in Sig. 6 to 9. The BAS signal is shown in FIG. 6. This signal was previously transmitted to a carrier frequency fT is modulated, as can be seen from FIG. In the invention is another Transmission method provided, as can be seen from Fig. # 8. Every picture element BE is transferred to an alternating current whose frequency is equal to or half that The sampling frequency of the pixels is * The pixel is analog according to its Value on the amplitude of the half-wave respectively. Transfer amplitudes of the period. A For example, a large value of the picture element becomes X a large value for the amplitude. In Fig. 38 is a half-wave is assigned to a picture element. The picture element BE of Fig. 6 is in 8 is allocated a half-wave BE of corresponding amplitude. The image sync signal is with the largest amplitude Bsy and the value UBE of Fig. 6 with the analog The UBE value of Fig. 8 is marked. In Fig.7 the modulation frequency is fM and in Fig.8 fMB. fMB is resp. Transmitting alternating current fT modulated on in Fig. 9. Included Then the two side frequencies fMBO and fMBU arise.

In the German standard, the number of pixels is 13 million per second with periods as an analog code, this results in 13 MHz.

With half waves this would result in a frequency of 6.5MHz.

An additional 1 hEz is required for the blanking time so that when using half waves as analog code 7.5MHz are necessary. In Fig.16 is now a combined analog-digital transmission is shown in which the composite signals analog and the audio signals are transmitted digitally. That via a filter BAS signal is fed directly / to a decoupler E.

It has a modulation frequency of 7.5 MHz and corresponds to the analog code in Fig. 8 The hue and color saturation are modulated with 0.6 MEz each, i.e. the size of the am- plituden determine the color or the color saturation.

Since the eye is more sensitive to hue, one can, under certain circumstances, the hue alternating current level put higher. This alternating current is fed to a modulator with a carrier of 7.5 MEz and fed through a filter Fi, which filters out the carrier and / the lower side frequency, fed to the decoupler, the upper side frequency is then 8.1 MHz, it should the color tone signals are transmitted. The color saturation signals S are also with an alternating current of 0.6 MHz in the same way. So this one will be again a modulator with a carrier Tr 7.5 MEz and fed through a filter Fi, the but sifts out the carrier and the upper side frequency, connected to the decoupler E.

The sound is digitized according to the principle of FIGS. 1 to 5. The period is provided as a code element. 250 Kbit, in the example KHz, are used for the sound at. for stereo for L + R and 250 kbit / s for stereo LR. The tone digitized with 250 KHz respectively. L + R becomes a modulator again fed with a 7.5 MHz carrier. With the following filter Fi, the carrier 7.5 MEz and the lower side frequency is now filtered out and fed to the decoupler E. With stereo, LR is also digitized, namely at 250 Kbit / s and fed to a modulator with a carrier of 7.5 MEz. The subsequent filter Fi filters out the carrier and the upper side frequency. The lower side frequency of 7.25 MHz is switched to the decoupler E. The alternating transmission current is generated in the oscillator Osz and fed via amplifier stages (not shown) to the output stage with modulator. #, # 6.9 MHz for the color saturation signal, 7.75 MHz for the digitized sound respectively. with stereo L + R signal and 7.25 turned on.

MHz for / L-R signal in stereo /. The BAS AC current of 7.5MHz can also be used for synchronization at the television receiver.

In Fig. 10 is another example for the transmission of the image and sound signals are shown. The BAS signals are generated analogously in accordance with FIG. 8 transmitted, but the picture element is passed through a period of an alternating current marked. With the traditional daytime speed 15 with blanking time are then / MHz / required. This alternating current is fed to a modulator Mo with a carrier of 50 CET. The filter Fi now screens the upper side frequency and the carrier so that the BAS signal is included in the lower side frequency of 35 MHz. The image signal then looks as shown in FIG. The chrominance or the Barbton and chroma signal and the tone signal is transmitted digitally, and although with the help of a binary code as FIGS. 1 and 2 show. For coding the The hue and the color saturation are provided 11 bit, so there can be 2048 possibilities be determined.

Since the hue is more sensitive to the eye, these 102 and the color saturation are assigned to 20 combinations, so that 2040 combinations are required. Another 2 bits are provided for the tone signals, which are also binary-coded according to FIGS. This is recorded in FIG. 14 MEz are used as the code alternating current. Time division multiplex with the multiplexer Mu in FIG. 10, the coded signals are continuously scanned and fed to a modulator with a carrier of 50 MEz. The filter Bi arranged below filters out the upper frequency ## and the carrier, so that the signal information of hue, saturation and T n is transmitted with the lower frequency of 36 MEz. The two alternating currents from 36 and MEz are transmitted via an amplifier V of the transmit # stage E iu- supplied with modulator, and modulated on the alternating current transmission.

A solution for the transmission of the signals is shown in FIG. in which the composite signals and the gon signals are directly imprinted on the alternating current transmission e.g. the FBÅS signals are analog and the audio signals are digital.

From the oscillator Osz the alternating current is sent to the amplifier V. In this the half-waves of the alternating current are transmitted analogous to the SSBAS signals, converted into corresponding amplitudes. The BAS signals e.g. analogous to Fig. 8. The audio signals are digitized in accordance with FIGS. 1 and 2. The time multiplexer Zmu takes over the supply of the values of the various signals. The alternating current encoded in this way then reaches the output stage 4E via an amplifier (not shown).

The BAS, hue-color saturation, appear in parallel by means of delay circuits and audio signals in series. An example of this is shown in FIG.

The first two half-waves are the saturation signal, the following ones i 2 half-waves for the color tone signal, the following 12 half-waves for the BAS signal and the last two half-waves are assigned to the sound signal. The two half-waves of the Tone signals represent 2 bits, since the tone signals are binary-coded according to Fig. 1 and z are. The composite signals are represented in analog form, i.e. the different amplitudes sizes correspond to the individual values.

In Fig. 13, the coding is done in the preliminary stage, men, so that the following amplifier stages can cause distortion. To this to avoid, proceed according to an arrangement according to Fig. 15 * In the penultimate one YerS amplifier stage VV the alternating transmission current is fed to output stage E once and single to a filter Fi. This is designed so that only the alternating current is blocked.

The next link Ph causes a phase rotation of 180 degrees, so that all harmonics coming from the filter are phase shifted by 1d0 degrees. These harmonics are fed back to the output stage so that they are there Cancel harmonics coming directly from VV. Fig. 10, for example, can also be switched in the same way if the modulation is carried out in the pre-stage, at the digital transmission of the color tone signal can only transmit the angle e.g. 0 to, 360 degrees, on can of course make the subdivision even finer.

In Fig. 14, the saturation and the hue signal were each with 2 half-waves These signals can also be transmitted as shown in FIG. The U-vector is transmitted with a half-wave and the V-vector with the following half-wave. The quadrant is digitally transmitted with the following two half-waves, namely by assigning a large and a small amplitude value to each half-wave. If the amplitudes are given 4 characteristic states, eg 10%, 40%, 70 »and 100% of the largest amplitude, then the WarD circle can be divided into 16 angles. You can now do something wide ## res #, namely expand the respective angle from 22.5 degrees to 90 degrees and transfer the U / V values that arise and then recalculate the values at the receiver.

One can use one alone or in addition to the previously mentioned method Carry out companding in the same way as the pulse code modulation system. In Fig.18 is a Color vector shown with a small angle. The value V would therefore be very small and would fall into the range of intoxication. For example, if the vectors are divided into 100 parts divided, for example 1/100 of the V value would be transferred with the value 5/100.

the value 2/100 with 8/100 etc. With the small U-values one would be exact proceed like this.

If all signals are transmitted serially as shown in Fig. 14, the analog values can be easily stored at the receiver with the aid of digitization, so that there is a delay on request can accomplish.

The decoupler in Fig. 16 is not absolutely necessary.

You can also switch lines by counting the BAS half-waves make.

In the case of angle companding, only the angles are expediently used q compand on the axes.

Claims (12)

Claims: 1. Method for the transmission of image and sound signals in television, characterized in that an analog or / ued digital coding the image and sound signals are carried out in this way with alternating currents of a frequency is given by the BAS signal element a half-wave (Fig.8, BE) or period of a Alternating current with half or with the pixel sampling frequency is assigned, where the size of the voltage values of the picture elements is analogous to the size of the amplitudes of half waves or periods are transmitted that the hue and color saturation signals analog and / or digital by a binary exchange code (Fig. 1 to 5), as well the tone, which are marked, the large and small amplitude values of the half-waves or reriods form the characteristic states in an uninterrupted Bolge are sent by positive and negative Balbwellen, the b "transmission takes place in parallel (Fig. 16) and / or in series (Fig. 14), carrier frequency through pre- or output stage modulation or directly serial / time-division multiplex by pressing the respective amplitude values on the Transmitting alternating current (Fig. 13). 2. The method according to claim 1, characterized in that the FBAS signals are fed to the transmission modulation stage via decouplers and amplifiers at carrier frequency, the hue-the saturation respectively. U / V and possibly quadrature and / or angular values and the sound signals one Before *; wr -Modulator supplied (Fig.16, MO), the audio signals are marked with a binary alternating current code (Fig.1-5), the Pre-Gufoe module carrier is the same as the coding frequency of the BAS signals (7.5 MHz), filters are also provided (Fig. 16, Fi), each of which sifts out a side frequency and the carrier, preferably a higher level is assigned to the color tone signal. 3. The method according to claim 1, characterized in that the hue, the dittigungs- and the tone signal is binary-coded only with an alternating current (Fig.10) and that a multiplexer is provided (Fig.10, TflU), which the code words of the different Arranges signals serially and a module tor feeds, and that the BAS signal of a modulator is switched on (Fig. 10, BAS, MO), the same carrier is assigned to both modulators, the two coding alternating currents are set so that the filters are filtered out when the two iveoberen or lower side frequencies with a carrier do not require any special quality. 4. The method according to claim 1, characterized in that the BAS signal analog (Fig. 8), the hue and color saturation signals analog and / or digital and the audio signals are digitally encoded with the same frequency (Fig. 13,14), that a time division multiplexer is also provided (Sig.13, Zmu), which controls the analog and digital code words seeriel and the alternating transmission current, to which the same frequency synchronizes, is assigned, in the amplifier stage (Fig. 13, V) further means are arranged, which analogously transmit the values of the alternating current to the alternating transmitting current. 5. The method according to claims 1 to 4, characterized thereby, that with pre-stage modulation and amplitude coding to the upstream of the output stage Stage (Fig. 15) a filter and a member for 180 degree phase shift (Fig.15, Fi, Ph) is switched on, the filter blocks the transmission frequency, the phase rotator is switched to the output stage in such a way that the harmonics cancel each other out. 6. The method according to claims 1 to 5, characterized in that that the color tone signal is transmitted as an angle of the color wheel, digitally if necessary in combination with the color saturation signal. 7. The method according to claims 1 to 5, characterized in that that the U and V vectors are transmitted as value signals (FIG. 1?) and that in doing so In addition, a quadrant (Fig. 17, Qu) or angle signal is provided; eÄ is. 8. The method according to claims 1 to 5, characterized in that that the color wheel is divided into a number of segments (e.g. squares) and Appropriate values are assigned, the coding being used for transmission purposes preferably takes place digitally with a two-stage or multi-stage amplitude code 9. Process according to Claims 1 to 5, characterized in that this is an angle companding , preferably at 90 degrees and that the resulting U / V values are transmitted, on the receiving side means are arranged from the respective angle and the transmitted U / V values, the color angle and the color saturation calculate, preferably the angle companding only when lying on the axis Angles is made. 10 * Process according to claims 1 to 5, characterized in that that in the case of small U / V values, a Serte companding takes place by adding the small values enlarged, converters are provided in the receiving station, which calculate the original values again. 11. experience according to claims 1 to 10, characterized in that that the sender and receiver have means for digitizing the analog values for the purpose of storage and delayed recovery. 12. The method according to claims 1 to 5, characterized in that that the Zeilnumschaltekriterion directly by counting the half waves respectively. Periods is gained;