DE2019859A1 - Method and circuit arrangements for the simultaneous transmission of two types of messages on a common transmission line - Google Patents

Description

, IBM Germany Internationale Büro-Maschinen Gesellschaft mbH

Boeblingen, March 9, 1970
ker-ba

Applicant: International Business Machines

Corporation, Armonk, N.Y. 10504

Official file number: New registration
Applicant's file number: Docket FR 9-69-010

Method and circuit arrangements for the simultaneous transmission of two types of messages on a common transmission line ^ "■." ■■

The invention relates to a method and circuit arrangements for the simultaneous transmission of two types of messages, the first of which in its original form covers the entire bandwidth and whose-second only part of the total bandwidth of a common Transmission line required, taking from the frequency spectrum at least one limited frequency band is cut out of the signals of the first message type and cut out in this Frequency band / these cut-out frequency bands the signals of the second message type are transmitted. In particular, this method is suitable for providing voice information and to transmit data information for more economical use of a transmission line at the same time. However, it is not limited to the transmission of voice and data; for example, data from different Sources to the appropriate number of recipients below Based on the method according to the invention, a transmission line can be transmitted. ·

009846/1608

The costs of data transmission systems are essentially determined by the line costs. If z. B; a common transmission line is used for a thousand-kilometer connection with a transmission speed of 2400 bauds, the line rental amounts to approximately 85% of the total costs, while only the rest of the costs relate to the transmission-side and modems at the receiving end. For this reason, a rented or occupied line should be used as optimally as possible will. This is in line with the purpose of the present invention.

According to the state of the art, various methods have already been proposed, using existing lines as well as possible to take advantage of. A first solution concerned the transmission at the highest possible speed: 4800 or even 9600 bauds. the The cost of modem equipment for such connections has increased significantly.

Another known solution consists in using the line not only for data transmission but also for voice transmission. For this purpose, circuit arrangements have been developed that alternately carry out voice and data transmissions. Switching from one operating mode to the other is carried out according to predetermined rules; either the available transmission time is distributed over the two operating modes or it is assigned according to priority, with the priority being given to the voice transmission. In the latter case, data transmission is only possible as long as no voice can be transmitted. It will be appreciated that such solutions can only be satisfactory when there is a limited amount of data to be transmitted.

It has also already been proposed to transmit data and voice at the same time «. A fixed proportion is also set out for this the channel bandwidth is reserved for data and the rest for voice. Only the lower and upper spectral ranges are shown

009840/1603

of the normal voice band transmitted over the line, the middle part of the spectrum cut out and transmitted through Data signals busy. If the tape used for data transfer is properly adhered to, it is possible to use the simultaneously for voice transmission and data transmission to be used with 1200 or 2400 bauds.

Obviously, this goal only comes with a loss of quality reached for voice transmission. The width of the cut out The frequency band for data transmission with 2400 bauds should be around 1000 Hz. This technique naturally reduces the level of intelligibility and also the Naturalness of a speech connection is very important.

The present invention is based on the object of an improved Specify method and circuit arrangements for its implementation, in which the simultaneous transmission of Voice and data over a common transmission line without any loss of intelligibility and naturalness of the voice and without waiting for the data.

This object is achieved for the method mentioned taking precautions of se measures, which are characterized in that on the receiving side the non-transmitted spectral components of the signals of the first message type due to level analyzes of the transmitted spectral components of the signals of the first message type in the vicinity of at least one of the limits of the frequency band reserved for the second type of message / the frequency bands reserved for the second type of message are recovered by synthetic level interpolations and added to the transmitted spectral components of the first type of message. ^:

Further improving design options and circuit arrangements for implementing the options mentioned are specified in the subclaims.

0C9846 / 16O8

A simple and an improved embodiment of the invention is shown in the drawings and is described in more detail below. Show it:

La the principle for accommodating data information within the frequency range of speech signals on the transmission line,

Fig. Ib the characteristics of the filters used for this,

* Fig. Ic the total spectrum of the speech signals to be transmitted in their original form,

Fig. Id shows the language spectrum after cutting out the

frequency band reserved for data transmission,

Fig. Ie the data spectrum packed into the remaining speech spectrum for transmission,

2a shows a first embodiment of the invention,

2b shows the arrangement of two analysis channels and two

Synthesis channels for the recovery of the complete speech spectrum on the receiving side,

2c shows the speech spectrum recovered with this first exemplary embodiment on the receiving side,

3a shows a second, improved exemplary embodiment according to the invention ,

3b shows the arrangement of two analysis channels, two synthesis channels and an additional analysis and 0G98A6 / 1608

Synthesis channel for the recovery of the complete speech spectrum and.

3c with the aid of the second exemplary embodiment

regained language spectrum. "

FIG. 1 a shows a possible basic arrangement according to the prior art for the simultaneous transmission of voice and data over the same transmission line. The voice information is fed in the conventional way via a subscriber circuit TS and transmitted via two filters arranged in parallel: a low-pass filter LPF and a high-pass filter HPF , which allow a frequency band in the area of the low-pass filter TPF and in the lower area of the high-pass filter HPF of the total speech spectrum to pass. The signals passing through these two filters are transmitted over the following transmission line. Data information is delivered simultaneously by a data transmitter DS and spectrally limited by a bandpass filter BPF. The bandwidth of this bandpass filter BPF is sufficient for the spectrum of the data information to be transmitted and is equal to the width of the frequency band by which the speech spectrum is clipped. Clipped voice information and complete ^ data information are transmitted over the same transmission line. ■

Fig. Ib shows the transmission ranges of the filters TPF, BPF and HPF as a function of the signal amplitude A on the frequency f. Correspondingly state-of-the-art receiving circuits, those without recovery of the cut-out language patchtral components working are not shown as they are fully symmetrical with the circuit arrangement for the transmission side according to FIG. la are. With the help of a band pass, the data are recovered for a data receiver, whereas a low pass and a High pass the Re & tSEektraX parts reserved for the Sprachbanä select l ^ nd via a corresponding subscriber circuit of the Feed in subscriber line. ;

009846/1608

The FIGS. lc, d and e each show, depending on the frequency f, the amplitudes A of the original speech signal, of the speech signal after passing the low-pass filter LPF and the high-pass filter HPF, ie a voice signal as it is trimmed and transmitted over the transmission line and as it is on the Receiving side arrives, and the frequency profile of the amplitude A of a combination signal transmitted over the line. The FIGS. Ia to · represent circuits and signals which correspond in their details to the state of the art.

ρ Fig. 2a shows transmission and reception circuits for the combination signal according to a first embodiment of the invention. In order to make the circuit diagram easier to understand, this figure shows the transmitting and receiving subscriber circuit TS of a subscriber, it being assumed that the subscriber on the other side is equipped with the same arrangement. The transmit circuitry is similar to that described in the prior art. The data information to be transmitted at the same time as the voice is also supplied here again via a data transmitter DS. The output signals of the data transmitter DS are advantageously combined with the remaining speech signals via the filters TPFl and HPFl by means of a summing amplifier SVl

t mixed and the resulting combination signal over the common transmission line is transmitted.

A combination signal arriving on the incoming transmission line three filters, namely the parallel connection of low-pass filter TPF2 and high-pass filter HPF2 and a bandpass filter BPF7, are fed. The output of the bandpass filter BPF7 leads to the data receiver DE and allows the further use of the received data.

'. The combined * outputs of the two filters TPF2- and HPF2 are parallel! the first input of a summing amplifier SV4

; supplied, furthermore eiaeK * niciiilinearen distortion circuit NLV, a bandpass filter BPF5 uM another bandpass filter BPF6. The exit the non-linear distortion adjustment NLV becomes two in parallel '' Series circuits discharged, on the one hand a bandpass filter BPFl,

009846/1608

an amplitude modulator Ml and a bandpass filter BPF2 and on the other hand a bandpass filter BPF3, an amplitude modulator M2 and contain a bandpass filter BPF 4. The outputs of these two series connections are the second and third inputs of the already called summing amplifier SV4 supplied. The outcome of this Summing amplifier SV4 leads to the subscriber circuit and further to the reception of the speech information by the subscriber.

It has already been mentioned that the outputs of the low pass TPF2 and the high-pass filter HPF2 as well as the two band-pass filters BPF5 and BFF 6 are fed. The output of the bandpass filter BPF5 runs through a rectifier Rl and a low-pass filter to TPF3 Input (1 - n) of a summing amplifier SV2 and to input η another summing amplifier SV3. In a similar way, the output of the bandpass filter BPF6 leads to the input η of the summing amplifier SV2 and to the input (1 - n) of the summing amplifier SV3. The outputs of the two summing amplifiers SV2 and SV3 are each fed to one of the two amplitude modulators iil and M2.

Fig. 2b shows the arrangement of the two analysis channels provided, which are used to measure the level energy, which in the two frequency bands are included directly next to the frequency band cut out of the speech spectrum, as well as the arrangement two synthesis channels, at least for the approximate reinstatement of the missing ones in the cut out voice frequency band Serving energy. Fig. 2c gives a speech signal spectrum again, as it is with the help of the circuits according to FIG. 2a on the Receiving side is to be achieved.

The mode of operation of the arrangement according to the invention will now be based on Ib to Ie and 2a to 2c will be explained. The combination signal, that is received via the transmission line is created by mixing the data signal to be transmitted from Data transmitter DS with the remaining speech signal that is transmitted via the two Filter TPFl and HPFl arrives. Fig. Ic represents the continuous Course of the original language spectrum. Between the

0098Ä6 / 1608

both residual spectral components according to Pig. ld are those from the data sender OS coming data information packed in with the help of the summing amplifier SVl. Fig. Ie shows the output of the summing amplifier SVl resulting spectral curve, which is sent over the transmission line. That from the language spectrum Cut out frequency band is through in Fig. Ie a dotted one! Curve eye shown.

It should be noted that the data signal of FIG. 2a is direct from the data transmitter DS to the summing amplifier SVl. It could | However, a bandpass filter can also be inserted into this data segment, whose The passage width is equal to the bandwidth of the cut-out spectral components of the speech signal, i. E. it could be a bandpass be provided? the only wipe the tape 1300 Hz and 2300 Hz lets through and thus ensures a clean delimitation. The arrangement of the filters TPFl -and HlPPl as well as the cut-out, tenen frequency band 'corresponds to the representation according to Fig. Ib.

With reference to Fig. 2a will now be explained how the combination signal is received and how the data and voice information can be made available again separately. The bandpass filter BPF7 is used to filter out the data signals arriving via the transmission line with the combination signal. This Bandpass filter BPF7 has a pass width of 1000 Hz, i. H. the bandwidth provided for data transmission in the selected example. The data signal thus fished out by means of the bandpass filter BPF7 is recorded and further processed by the data receiver DE. The voice signal is separated from the data signal by the low-pass filter LPF2 and the high-pass filter HPF2. These two filters match in their frequency position, in turn, that for the transmission side filters used, namely the two filters TPFl and HPFl. The filters TPF2 and HPF2 represent the residual spectral components of the speech signal below 1300 Hz and above 2300 Hz, which alone is the voice information transmitted over the line contain. The outputs of the filters TPF2 and HPF2 are connected to the input of the summing amplifier SV4, which continues to the subscriber circuit TS.

009846/1608

20198S9

* - - "'.-« .. a ■ „■ ■■■ - ■ - ■

The remaining part of the circuit shown according to FIG. 2a is used for at least approximate reproduction of the missing ¹ spectral components of the speech signal. These circuits will now be described in detail.

The bandpass filters BPF5 and BPF6 are used to delimit two frequency bands that are adjacent to the cut-out frequency band of the speech spectrum. In the example under consideration, the cut-out frequency band is the range from 1300 Hz to 2300 Hz. The bandpass filter BPF5 has a pass range from 900 Hz to I3QG Hz and the bandpass filter BPF6 one from 2300 Hz to 2700 Hz. The two bandpass filters thus define two "analysis channels" of the speech signal according to FIG. 2b. Their output signals should correspond to the level energy of these two analysis channels. The signals picked up within these two channels are rectified by rectifiers R1 and R2 and each fed to a low-pass filter LPF3 and LPF4. Further details of these analysis channels will not be described now, since their use in vocoders, ie in speech synthesis, is state of the art. Reference should be made to the literature on this, in particular to an article in the "Journal of the IEE", Volume 95, Part III, Number 37, Sept. 1948, "Analysis-Synthesis-Telephony with Special Reference to the Vocoder ¹¹ by Halsey and Swaffield and on the work of Flanagan "Speech Analysis, Synthesis and Perception", Springer 1965, chapter 8.1,

Pages 246 ff. and Chapter 8.3, pages 255 uff. ;

The output signals of the two low-pass filters TPF3 and TPF4 are thus characteristic of the envelope curves of the speech signal components in the ranges from 90 Hz to 1300 Hz and from 2300 Hz to 2700 Hz , as defined by the two band-pass filters BPF5 and BPF6. This information is therefore analysis results and is used to control the interpolation for the recovery of the signal level in the cut frequency band. To carry out different interpellations, the Sunaaian amplifiers SV2 and SV3 are used in a conventional manner using suitable multiplication factors. According to FIG. 2a, each input is this summing amplifier

009846/1608

- ίο -

with the effective amplification factor. The input η of the summing amplifier SV2 is connected to the output of the analysis channel BPF6-R2-TPP4, whereas the input (1-η) of this summing amplifier is connected to the output of the analysis channel BFF5-R1-TPF3. The summing amplifier SV3 is fed with its inputs of the same name but crossed over those of the summing amplifier SV2, ie. the input η is connected to the output of the analysis channel BPF5-R1-TPF3 and the input (1 - n) is connected to the output of the analysis channel BPF6-R2-TPF4. The factor η stands for any value less than i. In the chosen example it may be assumed that η «1/3. The two inputs of the Sunraier amplifier SV2 and SV3 are thus assigned the multiplication factors 1/3 and 2/3.

The output signals of the summing amplifiers SV2 and SV3 are thus indicative of intermediate energy levels depending on the frequency bands directly before rad after the cut out spectral component of the speech signal. These levels are used to modulate the amplitudes of two adjacent and partly overlapping frequency bands that just cover the frequency band that has been cut out. These frequency bands are shown in "synthesis channels" in FIG. 21, with the aid of which, as can still be seen, the speech components within the frequency band cut out on the transmission side can be replaced again 1200 Hz to 1900 Hz and a second one from 1700 Ez to 2400 Mas. Signals within these frequency ranges are generated as harmonics of the output signals of the low-pass filter LPF2 with the aid of the Hilf® Eisier straight-line distortion circuit Output signal spectrum * that lesi ümx Bingangiisilfiiala exhibits.

corresponds to speech synthesis

is in the already mentioned work 255 uff. described. What not-

It & m & xm V ^ rsenmgssdiiältungaß in detail, -sehaltkreise can be used. E.g. he is in "Acustica",

009846/1608

2018859

- ■ '· ■■ - ■ - 11 - ■■' ■. ■ ■

Volume 10 _r 1960 under the heading "The Vocoder for Transmitting 10 Kc / sec Speech over a 3.5 Kc / sec Channel ¹¹ by Schröder and David, pages 35 to 42, can be used. The output signal of the NLV attitude is a version enriched with harmonics of the speech signal range that was passed through the low-pass filter TPF2 and the high-pass filter HPF2. The distorted signal thus contains, in addition to other frequencies, harmonics in the speech spectral range that was cut out on the transmission side The bandpass filter BPF1 passes through harmonics within the range 1200 Hz to 1900 Hz and the bandpass filter BPF3 those between 1700 Hz and 2400 Hz.

About the synthesis of the speech information in the cut out frequency band to be carried out completely, the task now remains assign the correct level values to the harmonic signals emitted at the outputs of the bandpass filters BPF1 and BPF3 Output signal of the bandpass filter BPFl in the amplitude modulator Ml with the output signal of the summing amplifier SV2 is amplitude-modulated and similarly the output signal of the bandpass filter BPF3 im Treated amplitude modulator M2 with the output signal of the summing amplifier SV3. After the subsequent filtering in the two Bandpasses BPF2 and BPF4 appear in the corresponding signals dimensioned shape at the inputs of the summing amplifier SV4 as a replacement for the spectral antelles cut out of the language area from 1200 Hz to 190O Hz and from 1700 Hz to 2400 Hz.

In summary, therefore, in the summing amplifier SV4 the following spectral components combined:

a) The lower part of the speech spectrum that passes over the transmission line is directly overridden and selected by the low-pass filter TP ^.

b) The upper part of the speech spectrum, which is covered by the transmission

009846/1608

t _r

line transmitted directly and selected by the high-pass filter HPF2 will.

c) The middle part of the language spectrum that covers the two Synthesis channels BPF1-M1-BPF2 and BPF3HM2-BPF4 recovered will.

It should be mentioned at this point that the two also used Synthesis channels from vocoder technology are already known; therefore reference should also be made here to the literature already mentioned for further explanation.

The output signal of the summing amplifier SV4 is fed to the subscriber line via the subscriber circuit TS, which is thus a Receives speech signal that covers the entire spectral range, which was entered on the side of the page. This speech signal, which according to Flg. 2c corresponds to the spectrum shown, not exactly the original speech signal according to FIG The cut-out spectral component is not reproduced exactly. However, it becomes a satisfactory approximation for the speech signals submitted. -.

Fig. 3a shows a further embodiment of the invention, which an improved reproduction of the cut-out spectral components achieved. In the embodiment according to FIG. 2a, no speech information is transmitted within the cut-out frequency band. However, it is possible in the cut out To transmit frequency band information over the transmission line by combining the data signals with the voice energy are modulated from the cut frequency band and this Language information on the reception side with the help of an additional, third analysis channel can be worked out again. This technique should now be based on FIGS. 3a to 3c. ,.

Fig. 3a again shows the sending and receiving positions of a part

009846/1608

2019853

- 13 -

On both sides are the same facilities provided, and with reference to Fig. 3a should now be the transmitting part and the reception part are discussed. As in the embodiment described above, the entire speech range is divided into one frequency band below 1300 Hz via a low-pass filter TPFIl and a frequency band above 2300 Hz divided over a high-pass filter HPFIl and cut out the frequency band from 1300 Hz to 2300 Hz and kept free for data »A bandpass filter BPFIL picks out part of the speech spectrum between 1600 Hz and 2000 Hz on the transmission side , and an analysis channel of the same structure as described above, consisting of the said bandpass filter BPFIl, a rectifier RIl and a correspondingly designed low-pass filter TPF12 for the Envelope of the rectified signals is used for the spectral components between 1600 Hz and 2000 Hz. The output signal this analysis channel is used by means of an amplitude modulator MIO to modulate the data signals coming from the data transmitter DS used. The frequencies from the analysis channel used for modulation are very low; they are roughly in the range of 25 Hz. The modulated data signals and the two through the filter TPFIl and HPFIl transmitted speech spectral components are mixed by means of a summing amplifier SVIl, and the combination signal obtained in this way sent over the transmission line.

On the receiving side, the combination signal is fed to a bandpass filter BPF20, which picks out the frequency band occupied by the modulated data signals, in the example between 1300 Hz and 230OHz ₁ . A low-pass filter TPF13 and a high-pass filter HPF12 select the directly transmitted speech spectral components. Let us now consider the data branch first. The output of the bandpass filter b | pf20 is connected to the receiver DE, whereas a rectifier Rl4 and a low-pass filter LPF16 analyze the voice information transmitted over the transmission line due to the amplitude modulation, f r ' -. ■

In a similar catfish herds described for the first embodiment, the output signals of the low-pass filter TPFl3 and the high-

009846/1608

passes HPF12, which allow the voice spectral components transmitted directly via the transmission line to pass through, to the first input of a summing amplifier SVl4, further to the input of a non-linear distortion circuit NLV and to the input of two analysis channels with a bandpass filter BPPl8, a rectifier Rl2 and a lowpass filter TPFl4 on the one hand and a bandpass filter BPF19 , a rectifier R13 and a low-pass filter TPF15 on the other hand * The two band filters BPP18 and BPF19 limit two frequency bands, which are immediately below and above the cut out speech. frequency band. The bandpass filter BPF18 z. B. defining a frequency 'quenzband between 900 Hz and 1300 Hz and the bandpass BPFl9 such from 2300 Hz to 2700 Hz. According to the vorbesehriebenen simpler embodiment of the rectifier Rl2 and the low-pass filter are TPF14 excised for determination of the envelope of the means of the band-pass filter BPF18 Signal source is used, whereas the rectifier R13 and the low-pass filter TPF15 do the same for the energy in the pass band of the band-pass filter BPF19. Thus, three information energy envelope signals are obtained at the outputs of the three low-pass filters TiPFl 4, TPF15 and TPF16, namely the energy in the frequency range directly below the cut-out voice frequency band (here 900 Hz to 13 .. Hz), the energy in the frequency band immediately above the output -) cut voice frequency band (here 2300 Hz to 27OO EsD and the energy within the third frequency band (here 1600 Hz to 2000 Hz) within the voice spectral components cut out on the transmitting side

Thus, three points are now known from the speech signal spectrum that has been cut out and recovered: punk "; A according to Fig. 3c in the middle and the two points B and C on the Gärensen, D. The explanation based on the three points has only been chosen to make the description easy to understand. The three analysis channels used actually have a certain bandwidth, as shown in Pig-3b. What now remains is the explanation of the recovery of the speech spectral range between the points A, B and C. The method used is again

009846/1608

. / = ORIGiNALiNSPECTEO

an interpolation as in the first explained, simpler embodiment.

A buzzer amplifier SVl2 is used for interpolation between points B and A, which supplies the energy determined in the analysis channel BPF18-R12-TPF14 at its first input and via its second Input that receives certain energy via the analysis channel BPF20-Rl4-TPF16. The same applies to interpolation a summing amplifier SVi3 is used between points A and C, the one in the analysis channel BPF2O-R14-TPF16 certain energy and via its other input the energy determined by the analysis channel BPF19-R13-TPF15. The inputs of the two totalizing amplifiers SVl2 and SVl 3 are again designed with multiplication factors η and (1 -n) at their inputs, where η is a number smaller than 1. As an an example let η be chosen equal to 1/2. The output of the Suramier amplifier SVl2 is thus a hurried intermediate energy level, the between the energy level of the frequency range of the band filter BPF18 and is the energy level of the frequency range of the band filter BPF20. Similarly, the output of summing amplifier SV13 gives an intermediate energy level between the energy levels of bandpass filter BPF2O and that of the band filter BPFIt.

The two boundary band intermediate energy levels and also the energy level transmitted by means of the data modulation are used to recover the speech information in the cut-out spectral component. Three synthesis channels are used for this purpose, which act similarly to those according to FIG. 2a and are shown in FIG. 3a. The first synthesis channel consists of a bandpass filter BPF12, an amplitude modalator MIl and a bandpass filter BPFl3. BPFl2 defines a frequency band between the passbands of the bandpass filter BPF18 _t and the bandpass filter BPF2O? In the example chosen, the pass area of the band filter * BPF12 is the band between 1200 Hz and 1700 Hz. The second synthesis channel comprises a bandpass filter BPF14, an amplitude modulator M12 and a bandpass filter BPF15. The bandpass filter BPF14 defines the same frequency band as the bandpass filter BPFIl

009846/1608

ORIQlNAL INSPECTED

on the sending side; In the example chosen, a frequency band from 1600 Hz to 2000 Hz. Finally, the third contains a synthesis channel a bandpass filter BPF16, an amplitude modulator Ml3 and a bandpass filter BPF17. The bandpass filter BPF16 defines a frequency band between the pass band of the bandpass filter EPF20 and that of the bandpass filter BPF19? in the example chosen is the pass band of the bandpass filter BPF16 the range between 1900 Hz and 2400 Hz. It can be seen that the three bandpass filters BPF12, BPF14 and BPF16 thus cover the entire cut out voice frequency band. The pass bands of the bandpass filters are shown with a slight overlap. This is to be understood as given by the characteristics of the selected filters.

The three input bandpasses BPF12, BPF14 and BPF16 of the synthesis channels are fed in a manner similar to that described for the first embodiment, namely via a non-linear distortion circuit NLV, which is behind the low-pass filter LPF13 Emits harmonics of all spectral components contained in the original speech signal. The through the bandpass filters BPF12, BPF14 and BPF16 The parts of the band that have passed through are affected by the amplitude modulators MIl, M12 and M13 modulated. The amplitude modulator MIl is used for dimensioning the harmonics between 1200 Hz and 1700 Kz with the intermediate energy level from the output of the summing amplifier SVl2. The modulators Ml3 and Ml2 work accordingly for harmonics in the ranges between 1900 -ϊίβ- and 2400 Hz and 1600-He and 2000 Hz.

At the output of the synthesis channels, i. H. to the outputs of the bandpasses BPF13, BPF15 and BPF17, the speech information is in the ranges 1200 Hz to 1700 Hz, 1600 Hz to 2000 Hz and 1900 Hz up to 2400 Hz, thus the entire voice signal band cut out on the transmission side, is available again. The output signals of this three synthesis channels v / ground in the summing amplifier SVl 4 with the directly transmitted low and high frequencies of the speech spectrum range, which arrive via the two filters TPFl3 and HPFl2 -, mixed. Thus, at the output of the summing amplifier SVl4, the

0098 A 6/1608

Language information with sufficient quality again in its entirety to disposal. These voice signals, which have been reassembled, are offered to the subscriber circuit for audible reception.

After the description of the two embodiments of the invention Examples are now intended to provide additional details about the transfer process can be specified. Basically there are no restrictions. It is very suitable for data transmission the use of a digital modulation method with pulse trains consisting of data-identifying main pulses and leading ones and subsequent echoes. Such a modulation method has already been described in German Patent 1,292,167 and the corresponding French patent specification 1 504 609, which establishes priority. In general, such digital modulation methods are particularly important here very useful because they provide favorable filtering properties for filtering the transmitted signals.

As for the data transfer speed, is theoretical any solution possible. The frequency band required for data transmission is of course dependent on the transmission speed. However, since an intelligible voice signal is required to be transmitted, this is necessary for data transmission frequency band that can be cut out. Thus, it seems appropriate to set the data transfer speed to approx 2400 bauds, which, if the proposed digital modulation is used, a frequency band of approximately 1000 Hz must be provided for data. Although the choice of the transfer process depends on the tolerances allowed for the speech signal recovery is not a specific one in the present invention Define the transmission speed limit. j

Iv. ■ ■! ' "i ·

moreover is! to notice that the cut out of the speech spectrum, The frequency band reserved for data transmission is theoretically placed in any part of the speech spectrum could be. The speech signal characteristics, however, have a strong influence on the choice of the frequency band

009846/1608

the received voice signal. When the cut out frequency range If it were in the lower parts of the language spectrum, most of the basic information that passed through would be lost the vibrations of the vocal cords are given because corresponding sounds are in the lower frequency range of the speech spectrum high energy content. If, on the contrary, the cut-out frequency band is in the upper ranges of the speech spectrum If this were to happen, the basic information of the sibilants that are not based on vocal cord vibrations would be lost because these Sounds just have their maximum portion in the higher frequency ranges ". A frequency band in the middle of the Language spectrum cut out to take account of the circumstances presented. A frequency band from 1300 Hz to 2300 Hz was established therefore suggested.

It is to be investigated whether the recovery of the cut out frequency band of the speech spectrum, which requires a certain expenditure of time for the ongoing operations, does not require the provision of delay units in the individual signal paths, which process the corresponding spectral components of the speech signals. Experimentally, it has been found that the differences in runtime have no significant influence on the intelligibility of the language. This is presumably due to the fact that the course of the speech signals over time is relatively slow and that the slight delay in the recovery of the middle speech range with respect to the lower and upper spectral components is therefore imperceptible. However, it would be easily possible to accommodate such delay time differences in the subchannels, namely as. B, behind the outputs of the filters TPF2 and HPF2 according to FIG. 2a or behind the outputs of the filters TFFl3 and HPF12 according to S ¹ Ig. 3a.

It can be seen from the foregoing that the present invention is neither limited to the proposed application for language and asked, nor to the given exemplary embodiments.

009846/1608

It enables further variations. It could e.g. B. a limited amount of analog information of the cut out speech area via the transmission line in addition to the help the voice-modulated data transmitted information is transmitted. For this purpose, one or more channels could be defined on the transmission side, which specify the corresponding energy components, which partially or completely the cut out Cover the frequency band of the language area. The information energy components analyzed in this way would then be used for amplitude modulation several carrier areas used, the resulting modulation signals transmitted over the transmission line and on the Receiving side demodulated in order to individually recover the contained information. For this purpose, a corresponding arrangement of synthesis channels would have to be established, the number of which equals the The number of analysis channels provided is.

As already explained, the signals of such analysis channels have frequencies in the range of approximately 25 Hz. So be each covers bands of about 50 Hz. This extended procedure can thus be a broadening of the cut out Require frequency band. The need for additional effort increases the complexity and also the costs of the system. the Use depends on the special conditions that have to be met.

The present description is not to be regarded as limiting. Numerous modifications of the invention are possible without departing from its subject matter and scope.

009846/1608

Claims (8)

- 20 - PATENT CLAIMS Method for the simultaneous transmission of two types of machine, the first of which in its original form is the entire Bandwidth and the second only part of the total bandwidth of a common transmission line, wherein cut out at least one limited frequency band from the frequency spectrum of the signals of the first message type and the signals of the second message type are transmitted in this / these cut-out frequency band (s) will, characterized, that on the receiving side the spectral components not transmitted (1300 Hz - 2300 Hz) of the signals of the first type of message (speech) based on level analyzes of the transmitted Spectral components (below 1300 Hz and above 2300 Hz) of the signals of the first message type (speech) in the vicinity of at least one the limits (900 Hz - 1300 Hz and 2300 Hz - 2700 Hz) of the frequency band (s) reserved for the second message type (data) (1300 Hz - 2300 Hz) recovered by synthetic level interpolations and additively the transmitted Spectral components (below 1300 Hz and above 2300 Hz) of the first type of message (voice) added / ground. 2. The method according to claim 1, characterized in that that on the transmission side at least part of the frequency spectrum of the signals of the first message type (speech) cut out spectral components (1600 Hz - 2000 Hz) in at least rectified in an analysis channel and only permeable through one for the envelope of the rectified signals Low-pass filter (TPF12) is performed, 009846/1608 that the signals of at least part of the frequency spectrum (1300 Hz - 2300 Hz) of the second type of message (data) for joint transmission with the directly transmitted spectral components (below 1300 Hz and above 2300 Hz) of the signals of the first type of message (voice) through the output envelope " Nale of the aforementioned analysis channel (s) are amplitude-modulated will and that on the other hand, analyzes of this amplitude-modulated on the receiving side Signals are carried out and the signals thus obtained for further synthetic level interpolations within at least a specified range (1600 Hz - 2000 Hz) of the not directly transmitted spectral components (1300 Hz - 2300 Hz) of the signals of the first message type (voice) can be used. 3. The method according to any one of the preceding claims, characterized in that the first type of message is voice information and the second type of message includes data information. 4. The method according to any one of the preceding claims, characterized in, that from the spectrum of signals of the first type of message (voice) to transmit the signals of the second Message type (data) cut out spectral components a lower frequency limit above 1000 Hz and an upper one Have a frequency limit below 3000 Hz. 5. Circuit arrangement for carrying out the method according to one of the preceding claims on the transmission side, characterized by means of a state-of-the-art parallel connection of a low-pass filter (LPF 1/11) and a high-pass filter (HPF 1/11) whose inputs are the signals to be transmitted (300 Hz - 3400 Hz) are fed to the first type of message (voice) and which of their outputs are only those in spectral components lying in their respective passbands 0098Λ6 / 1608 (below 1300 Hz and above 2300 Hz) to the first input of a downstream analog adder (summing amplifier SV 1/11) the second input of which is fed with the signals (1300 Hz - 2300 Hz) of the second type of message (data) and its output with the input of the outgoing transmission line is connected. 6. Circuit arrangement according to claim 5 for implementation on the transmission side of the method according to one of claims 2 to 4, characterized by one with its first input and its output in the supply of the signals of the second message type (data) to the second input of the analog adder (summing amplifier SV 11) inserted before the outgoing transmission line Amplitude modulator (M 10) and through a bandpass filter (BPFIl), which covers at least one part (1600 Hz - 2000 Hz) of the spectral components cut out of the frequency spectrum of the signals of the first type of message (speech) (1300 Hz - 2300 Hz) is permeable, its input in addition to the parallel connection of low-pass (TPFIl) and high-pass (HPFIl) the entire spectrum of the signals to be transmitted (300 Hz - 3400 Hz) is fed to the first type of message (voice) and its output via a rectifier (RIl) with one only for the envelope of the rectified signals of the selected frequency band (1600 Hz - 2000 Hz) of the first Message type (language) permeable further low-pass filter (TPFl2) is connected, the output of which in turn leads to the second input of the amplitude modulator (MIO). 7. Circuit arrangement for carrying out the method on the receiving side according to one of claims 1 to 4, characterized in that that the. incoming transmission line with the inputs of the parallel connection of a low-pass filter (LPF 2/13) and a high- 009846/1608 passes (HPF 2/12) is connected, which from their outputs only the directly transmitted spectral components (below 1300 Hz and above 2300 Hz) lying in their pass bands let the first type of message (voice) reach the first input of a first analog adder (SUMMIER amplifier SV 4/14), that a first and a second synthesis channel are provided, the first from the series connection of a first bandpass filter (BPF 1/12), a first amplitude modulator (M 1/11) and of a second bandpass filter (BPF 2/13), the output of which connects to the second input of the first analog adder (summing amplifier SV 4/14) is connected, that the second synthesis channel from the series connection of a third bandpass filter (BPF 3/16), a second amplitude modulator (M 2/13) and a fourth bandpass filter (BPF 4/17), the output of which connects to the third input of the first analog adder (Summing amplifier SV 4/14) is connected, that at the output of the first analog adder (summing amplifier SV 4/14) the entire spectrum of the recovered received signals of the first message type (voice) is output, that the first and second bandpass filters (BPF 1/12 and BPF 2/13) define the bandwidth of the first synthesis channel (1200 Hz - 1900 Hz), the part of the from deir. Spectrum of the first type of message (Language) cut out spectral components (1300 Hz - 2300 Hz) covered, that the third and fourth bandpass filters (BPF 3/16 and BPF 4/17) define the bandwidth of the second synthesis channel (1700 Hz - 2400 Hz), the remainder or at least a further part of the cut out from the spectrum of the first message type (language) Spectral components (1300 Hz - 2300 Hz) covered, 009846/1608 that the outputs of the parallel connection of low-pass (LPF 2/13) and high-pass (HPF 2/12) also with the inputs of a fifth Band pass (BPF 5/18) and a sixth band pass (DPF 6/19) are connected, that the fifth bandpass filter (BPF 5/18) with its pass band a first analysis channel (900 Hz - 1300 Hz) in the lower spectral range and the sixth bandpass filter (BPF 6/19) with his Passband a second analysis channel (2300 Hz - 2700 Hz) in the upper spectral range of the directly transmitted spectral components the first type of message (voice), in each case at the limits of the cut-out frequency band (1300 Hz - 2300 Hz), determine, that the output of the fifth bandpass filter (BPF 5/18) via a first rectifier (R 1/12) and, according to the state of the art, via a low-pass filter (LPF 3/14) that only allows the envelope of the rectified signals to pass through to the first Input (1 - n) of a second analog adder (summing amplifier SV 2/12) and, if only two analysis channels are provided, is led to the second input (s) of a third analog adder (summing amplifier SV 3/13), that the output of the sixth bandpass filter (BPF 6/19) via a second rectifier (R 2/13) and, in a known manner, via a low-pass filter (LPF 4/15) to the first input (1 - n) that is only permeable to the envelope of the rectified signals of the third analog adder (summing amplifier SV 3/13) and, g-l · «· if only two analysis channels are provided, to the second input (s) of the second analog adder (Sunmier amplifier SV 2/12) is performed, that a seventh band-pass filter (BPF 7/20) with a pass band (13 (X) Hz - 2300 Hz) for the signals of the second type (Data) is provided, whose input in addition to the parallel connection of low pass (TPF 2/13) and liochpaß (HPF 2/12) with 0 0 9 8/46/1608 the incoming transmission line is connected and at its output the received signals of the second message type (Data) are submitted, that the output of the second analog adder (summing amplifier SV 2/12) to the second input of the first amplitude modulator (M 1/11) and the output of the third analog adder (summing amplifier SV 3/13) to the second input of the second Amplitude modulator (M 2/13) are performed and that the inputs of the first and second synthesis channel (bandpass filters BPF 1/12 and BPF 3/16) either by a band generator be fed that emits at least the frequencies / which are required to fully feed both synthesis channels, or that the inputs of the first and second synthesis channel (bandpasses BPF 1/12 and BPF 3/16) through a non-linear distortion circuit (NLV), the input of which is also connected to the output of the parallel circuit from the low-pass filter (LPF 2/13) and high-pass filter (HPF 2/12) and their output, according to the state of the art, by non-linear Distortion obtained harmonics of the output signals of the low-pass filter (LPF 2/13) of the parallel circuit are emitted. 8. Circuit arrangement according to claim 7 for implementation on the receiving side of the method according to one of claims 2-4, characterized in that that parallel to the input of the first and second synthesis channel (Bandpasses BPF 1/12 and BPF 3/16} a third synthesis channel is fed from the series connection of an eighth bandpass (BPF14), a third amplitude modulator (Ml2) and e4.nes ninth band pass (BPF15), the output of which is an additional, fourth input of the first analog adder (summing amplifier SV14) is connected, 0 0 9846/1608 that the eighth and ninth bandpass filters (BPF 14 and BPF 15) the bandwidth of the third synthesis channel (1600 Hz - 2000 Hz), which is within a specified range in the not directly transmitted spectral range (1300 Hz - 23OO Hz) of the Signals of the first message type (speech) are present, that a third, in the frequency range of the third synthesis channel, the third analysis channel from the series connection of the seventh band pass (BPF20), a rectifier (Rl4) and Another low-pass filter (LPF 16) is provided that this third analysis channel from the incoming transmission line is fed and that the output signal of the third analysis channel to the second input of the third amplitude modulator (Ml2) in the third Synthesis channel and also to the second inputs of the second and third analog adders (summing amplifier SV12 and SVl3) is performed. 009846/1608 Blank page