DE3134328A1 - Method for operating a PCM system and for operating a memory storing PCM signals - Google Patents

Abstract

In this method, the PCM signals correspond to a sequence of analog signals, a small proportion (S), for example 1% or 15%, of the PCM signal digits representing changed, that is to say impressed special digits (S) which in each case exhibit regular time intervals (ts) filled with a multiplicity of unchanged PCM signal digits, and form an impressed noise or an impressed interference with respect to the unchanged PCM signals. The special digits (S) represent additional stored digital information and are treated like digits of the PCM signals during transmission between connections or on retrieval of the PCM signals, that is to say they are not suppressed but also supplied to one or more connections or loads, for example a loudspeaker or a screen, as superimposed noise or as superimposed interference. The special digits (S) represent arbitrary information, which can be input by a user of the connection, that is to say not only markings which, when needed, are separately fed to a load by filtering out the unchanged PCM signal digits, independently of whether the PCM signals are also simultaneously fed to one of the connections or loads. The PCM signals can be words (bytes) consisting of bits which correspond to the difference of the respective analog signal from a reference value which is constant in time, the special digits (S) being impressed at least-significant positions (N) within the words (bytes). The PCM signals can also represent, for example, delta-modulated analog signals. <IMAGE>

Description

Procedure for operating a PCM system and for loading

drove a memory storing PCM signals.

The invention relates to an improvement on an older method to operate a special communications system with pulse code modulation (= PCM). The invention was made for the multiple exploitation of a PCM storing signals Telephone answering machine, which in addition to the in In addition, the answer stored in PCM technology is not receivable for callers Way, private special information that can be saved by the phone owner, e.g. short numbers Addresses and appointments. However, the invention is also suitable for all areas of communications engineering in which PCM signals are transmitted and / or get saved.

The invention is based on what is mentioned in the preamble of claim 1 older procedure from that for itself already by the not pre-published Documents DE-OS 30 48 628 and 31 12 803 is described.

However, these older publications per se relate to more specific ones Method, namely for the operation of a telephone answering machine with a magnetic bubble memory, which also stores very special PCM signals, namely delta modulated ones Signals.

In contrast, the invention can be any PCM signals. PCM signals can be structured very differently, see e.g. the essays with the title terms of digital transmission technology "in the magazine "Frequency" 32 (1978) Issue 8 to 10.

PCM signals can therefore be formed by words, often called bytes, for example where the individual words have multiple digits, e.g. 8 or 16 or 32 bits, can contain and where the individual digits of each word are different Have significance. 1 shows an example of a transmission of bytes or words, where it was assumed that each word is 8 bits and that the least significant bit N of each word is the last bit and that the Most significant bit H of each word as the first bit within the relevant word is transmitted. Such PCM signals generally correspond to a respective one Analog signal value, based on a reference value that is constant over time. Such PCM signals with words containing digits can also be used in the invention, not just delta modulated signals.

There are also PCM signals in which the respective PCM signal is the difference of the respective analog signal value, not to a reference value that is constant over time, but corresponds to a temporally preceding value of the same analog signal. This is the differential pulse code modulation (differential pulse code modulation = DPCM), whereby all these PCM signals, which here represent differences, can also represent words each containing several digits.

The simplest forms of DPCM signals are those, even in the older ones mentioned documents described, delta modulated signals in which the relevant difference only through a single digit instead of a byte or word. In the invention, the PCM signals can also can be formed by any kind of DPCM signals.

So the invention is not directed to a specific type of PCM signals limited, as later with reference to FIG. 2 and 3 shown in more detail will be.

The invention can also be any PCM system, which, with or without intermediate storage in a memory, PCM signals between connections transferred - not just to a special telephone answering machine as with the older publications.

The invention can also be, for example. any PCM telephone switching system or a PCM wide area transmission system. In addition, it can with the invention not only, as with the older publications, to a PCM signals storing magnetic bubble memory act, but to any PCM signals storing memory, e.g. also a PCM video magnetic tape memory, also a Videophone telephone answering machine that stores a picture by means of PCM signals, also any other types of memory storing PCM signals, e.g. a PCM record, PCM tape cassette or a semiconductor memory storing PCM signals.

With the older method, as with the invention, there is a smaller one Proportion of the individual PCM signal digits changed or impressed, with the impressed Special digits also to the PCM signal receiver or analog signal receiver as superimposed noise can also be transmitted and / or stored. Even with the older one Processes thus form the impressed special digits respectively a noise or a Disturbance which superimposes the actual PCM signal, namely the stored response there are and are passed on as noise or disturbance, there to the calls: When older methods, however, these special digits each represent markings, namely e.g. markings for the start or for the end of the answer, i.e. the saved one PCM signals, or it provides markings for the start and / or for the end of sections of this as PCM Signals stored answer In the invention, however, the special digits are not used, at least not exclusively for marking, i.e. not, or not exclusively, for synchronization. In the case of the invention, the special digits contain independent, different ones additional information, i.e. from the answer that forms the stored PCM signals independent information, e.g. those notes of the phone owner, which this in his telephone answering machine memory additionally, perhaps via addresses Wants to save appointments and / or phone numbers of business friends. In the invention These special digits also provide any other information instead of just showing markings of the PCM signals, as will be explained in more detail later will be explained, with these special digits in the invention for themselves if necessary- also pulse-modulated additional information, for example also teletype signals or other delta-modulated information, e.g. as well as the actual PCM signals, can form.

The older method, like the invention, already has the advantage that it allows PCM signals of any kind to be transmitted in any way and / or to store9 as already described above; - Special digits of the PCM signals to imprint educational information, e.g. by overwriting, which, although the Receivers of these PCM signals a certain amount of noise or

cause some disturbance of the PCM signals, this being noise or this interference is so small that it is this receiver of the PCM signals either do not attract attention at all or do not bother him significantly; - the capacity the time channels of the PCM system or the capacity of the one storing the PCM signals Memory to fully exploit the PCM signals by no longer own time channels within the time frame of the PCM signals or in the relevant one Memory related areas for the information content of the special digits, must be reserved while reducing the duration of the analog signals; as - the stored PCM signals despite the noise caused by the special digits or in spite of the resulting disturbance, it is still more typical for PCM signals Way de facto. to transmit the required analog signals with high precision and / or save.

In the prior art, further methods are known, which are similar, but different from the older procedures and which, moreover, are not all of those advantages mentioned above enable both the older procedures as well as the invention.

For example, DE-PS 28 04 150 describes a method in which the special digits, called additional bits there, represent a special type of marking, namely above all parity bits. As is well known, parity bits are only used for checking purposes of the bits or words and usually do not become themselves after decoding also transmitted to the recipient. The special digits are used there for checking the actual PCM signals to which the relevant special digit is responded to is imprinted at the lowest point for an even better sound quality than to enable without parity bit.

Such special digits are therefore not immediately available to the recipient additionally fed in as superimposed noise. So they do not represent a disturbance which is intentionally also sent directly to the receiver of the PCM signals will. In particular, with this state of the art, the special digit does not serve to a conference and / or storage of any additional To enable information independent of the PGM signals. Besides, this is known methods restricted to special PCM signals, namely to those which contain words (bytes) each with several digits.

In addition, the further described in DE-AS 28 27 040 This method does transfer PCM signals of any kind, including delta-modulated signals Signals, described, where special digits are also impressed on the PCM signals and where these special digits are any additional information, independently of the PCM signals. With the procedure described there however, see in particular column 3, lines 36 to 41, as well as column 5, line 20 to column 6, line 3, the special digits that is, the one through the special digits formed additional information, not the receiver of the PCM signals as superimposed Noise additionally fed in. Instead, what should be formed by the special digits Noise or

interference formed by the receiver of the PCM signals, with the help of a corresponding Expenditure on components and process steps are kept away. So will there indicated that the received special digits by uniform filler bits, e.g. by all binary zeros, are replaced, after this replacement these filler bits together be fed with the PCM signal to the receiver of the PCM signal. In this case the filler bits only mark the PCM signals without any additional ones Information, namely markings, which then only have a time grid for represent the received sequence of analog signals. In the invention, however the special digits are neither filtered out nor replaced by filler bits, but just as the PCM signals to the receiver these PCM signals, albeit as (more or less unnoticed) noise.

The invention has, in comparison to the first two mentioned, older Procedure, with the additional advantage that it allows - those through the special digits formed any additional information with very little effort, viz without demodulation of the PCM signals and without an additional frequency filter and without Complicated crossover, directly from the PCM signals in a particularly simple way, namely just by touching, to regain, and - the special digits for any additional information, instead of just for markings related to the PCM signals, to be able to exploit.

These additional advantages of the invention are shown in the characterizing part of claim 1 specified additional measures achieved.

The further developments of the invention specified in the subclaims allow further advantages, namely the measure according to patent claim 2, due to the imprinted special digits one, in comparison to the frequency band of the dem PCM signal underlying analog signal, relatively high-frequency weak interference or to form a relatively high-frequency weak noise, which in particular with PCM signals that represent a video recording, a slight flicker on the screen corresponds to; as well as 3, due to the special digits one, in comparison Relative to the frequency band of the analogue on which the PCM signal is based - - -gnais, vscnwacne disturbance or a relatively low-frequency, weak hum or To form noise, which is particularly common with PCM signals (such as in telephone systems), which anyway only has an analog signal with a limited frequency band between one lower Limit frequency (400 Hz) and upper limit frequency (3600 Hz), even possibly can be in the frequency range below the lower limit frequency.

The invention and developments thereof, together with special ones, in particular Advantageous applications are to be exemplified in the following with reference to the in Schemes shown in FIGS. 2 and 3 of the structure of PCM signals with impressed Special digits are further described, with the figure 2 PCM signals, which from Words (bytes) are formed with several digits each, with some of these Words whose least significant digits have been changed by stamped S special digits are, as well as 3 delta-modulated PCM signals, which at longer time intervals of the special digits S are interspersed, show.

In the embodiment shown in FIG. 2, the PCM signals each represents words or bytes, which are here in the Pig. 2 in a symbolic way only or also genuinely separated from one another in time by marker bits T. can. These PCM signals correspond to a sequence of values of an analog signal, whereby the PCM signals were formed by coding the analog signal. A minor one Share of PCM signal digits, e.g.

1% or 15% of the same, are respectively changed, these being changed Signal digits, see S, here the least significant digit N of individual words replace, cf.

also FIG. 1. In this case, the PCM signals correspond in each case E.g. words consisting of eight bits, which are the difference of the respective Analog signal value correspond to a reference value (zero) that is constant over time.

The special digits S, each represented e.g. by binary zero and one bits can be formed, each have regular time intervals ts among themselves, with a large number of unchanged digits between the individual special digits of the PCM signal. In the simplest case, the relevant time intervals are as well in Fig. 2 and 3, each other always the same size. In principle, however, are also other regular time intervals are possible with the invention, e.g. time intervals which between the first special gits S each have a time interval from a first value ts, in which, however, between second, further not shown in the figures Special digits are each time intervals of a different value, e.g. three times each greater time intervals than the time intervals ts.ß shown in FIG. 2 in each case represent the special digits, which are imprinted on the PCM signals formed here from bytes are, a noise or an impressed disturbance for the receiver of the PCM signals respectively.

for the receiver of the analog signals that have been converted back by decoding if the special digits are digital additional information stored represent whose transmission speed is slow compared to the transmission speed the PCM signal digits, however, when transmitting the PCM signals or the These special digits S treated these corresponding analog signals as if they Digits of the PCM signals would be. The rushing influence of the special digits on the through Decoding of the reconstructed corresponding analog signals is therefore used for the receiver which does not suppress PCM signals, but rather one or more of the receivers or

Connections or consumers as superimposed noise or as superimposed Disturbance also forwarded. These special digits S are thus e.g. a loudspeaker or to a screen of the receiver as noise or interference, e.g. So as hissing, humming, flickering or superimposed clouds, instead of sifted out or instead of through Fill bits to be suppressed.

It has been shown that the special digits S in by words formed PCM signals, see Fig. 2, in which the special digits at least significant Places are impressed, each with a relatively high-frequency noise close to the upper one Represent the frequency limit of the analog signals. This high frequency noise, high frequency with regard to the frequency band of the analog signal, it is particularly annoying because of this not because the amplitude of this high frequency noise is usually very small versus the amplitude of the entire analog signal. An overlay of the addition impressed information, which by any user the PCM signal in the form was superimposed by special digits S, can therefore according to the one shown in FIG Consume can be carried out when the noise generated by the special digits As high as possible in the area of the upper frequency limit of the frequency band of the Analog signal or even above this, with an amplitude that is noticeable for the receiver receivable upper frequency limit should be. In the invention, then the high-frequency noise generated by the special digits is not caused by it serving sieve means or sieved out by suppressing means.

The example shown in FIG. 3 is delta-modulated Signals, - i.e. PCM signals in which the difference between the respective analog signal value to a temporally preceding value of the same analog signal as the basis for the modulation of the analog signals is used. In contrast to that shown in FIG Method, the method shown in Fig. 3 does not have multi-digit words per word on. The method shown in FIG. 3 is, so to speak, Words that each consist of only one digit, e.g. consist only of a single binary zero or binary one. A small proportion the POI signal digits is also changed here at regular time intervals by ts there special digits S are stamped, which are additional digital information represent whose transmission speed is low compared to the transmission speed of the delta-modulated PCM signals. Here, too, the special digits S can each from any connection user and any additional information represent.

As in the example shown in FIG. 2, these represent special digits S in FIG. 3 not only represents markings which somehow relate to the sequence of the analog signals or are related to the sequence of PCM signals. The Sonderdîgits S provide of the invention not only markings e.g. for synchronization or Represent parity bits, not just markings for the start or end of the PCM signals, - With some of the special digits S in special cases also once in the invention in addition, such marks may occasionally correspond. Ask instead in the case of the invention, these special digits S are generally any 5 of the analog signals independent additional information, which by pulse modulation e.g. also Delta modulation, generated from this additional information.

The special digits S are also used in the method shown in FIG The PCM signals are fed to the receiver as if they were delta modulated components of the PCM signals would be.

These special digits S represent in the method shown in FIG. 3 then a relatively low-frequency superimposed signal for the receiver of the PCM signal Noise related to the frequency band of the analog signal corresponding to the PCM signal. That generated by the special digits S. So noise has frequencies those in the range of the lower that can be received with an amplitude that is noticeable to the receiver Limit frequency of the frequency bath of the analog signal lie, or even below this Cut-off frequency. In the invention, the complexity of components and process steps for filtering out the low-frequency noise formed by the special digits S, too avoided in the method 7 shown in FIG. The example shown in FIG. 3 is therefore particularly advantageous when the PCM signal is an analog voice signal from e.g. 400 to 3,600 Hz. In this case, the recipient receives the PCM signal, which also includes the special digits S as low-frequency noise receives, also the special digits S, but with frequencies corresponding to hum, those in the lower range of the speech frequency band that he can detect or below this speech frequency band lie. In the method shown in FIG. 3, the additional information, which corresponds to the special digits S, almost or completely inaudible to such a voice analog signal receiver.

In addition, the amplitude is that formed by the special digit S. Noise or hum in both that shown in FIG. 2 and that shown in FIG Procedure very small. This is one of the reasons why it is hardly noticeable for the recipient or completely imperceptible to him.

Because in each of the two methods shown in FIGS the special digits S, which are also transmitted as noise or interference, in each case hardly or at all are not perceived by the receiver of the PCM signals, no effort is required, to filter out these special digits S or to delete them using filler bits before one the PCM signals to the relevant receiver of the PCM signals.

In the two methods shown in FIGS. 2 and 3, therefore, the capacity is the time channels of the PCM system or

the capacity of the PCM signals -.storing memory full for the PCM signals can be exploited by no longer having their own time channels within the Time frame of the PCM signal for the information content of the special digit in a Way must be reserved which the duration of the transmitted as PCM signals or stored analog signals are reduced. It is also no longer necessary in one Memory related areas for the information contained in the special digit to reserve, reducing the duration of the analog signals stored as PCM. The capacity of the time channels of the PCM system or the PCM signal memory is available so still practically fully available for the analog signal.

Only a small one, based on the frequency band that the receiver can detect of the analog signal, e.g. low-frequency or high-frequency, noise is included Particularly small amplitudes are faded into the analog signal through the special digits. In the case of speech-analog signals, this noise corresponds to depending on the application of the method according to FIG. 2 or FIG. 3, a high-frequency quiet one Hissing or a low-frequency soft hum. In the case of picture-analog signals the noise is either a high-frequency, weak flicker or a low-frequency one, as desired weak strip-shaped veil or cloud formation or strip-shaped shadowing and lightening.

The PCM signals can therefore despite the impressed by the special digits Noise continues to de facto with high precision, which is typical for PCM signals transmit or store the respectively desired analog signals, preference being given rather a procedure according to

Fig. 2 or rather according to Fig. 3, depending on which frequency of the or what kind of noise or. disturbance for the recipient on is at least annoying.

In each of the methods shown in FIGS. 2 and 3, the special digits or any corresponding additional information with very little effort can be recovered directly from the PCM signals in a particularly simple manner, - by the way, also according to

the blanking process mentioned in DE-AS 28 27 040 using from an additional marking of the time cycle that the special digits have.

In any case, there is no prior demodulation for this purpose the PCM signals in a demodulator still have a previous filtering by means of a Anal8g frequency filter, a complicated crossover is absolutely necessary.

The special digits or any corresponding additional information can in fact simply from the superposition of the PCM signals with the special digits can be recovered by blanking out the special digits S, e.g. by means of a switch clocked in the appropriate rhythm, which the recipient of the special digits S or the recipient of the relevant arbitrary information through this blanking only connects to those time channels that carry these special digits S. Through this very simple blanking of the special digits, you can filter out the others unchanged PCM signal digits, whereby here the corresponding analog signal is sent to the receiver the arbitrary additional information is not passed on.

The recipient of the additional information thus receives his information in pure form without noise or

Interference from the PCM signals, but the receiver of the PCM signals thus receives its analog signals in contaminated form together with the additional ones Information, but for him only a certain noise or a certain disturbance represents. It is at the finding, above all, without further ado possible, at the same time, both the one recipient his information by blanking to be forwarded to the other recipient as well, which also contains the special digits S. PCM signals or

the correspondingly noisy analog signal with tolerable low crosstalk to forward without the two recipients in any way interfering with each other. To the Suppression of a disturbance does not necessarily require further effort.

In the following, special developments of the invention will be discussed, which have a special meaning for a telephone answering machine. This training particularly relates to the additional use of the memory of a telephone answering machine as a memory for additional information, this memory in particular a non-mechanical speech memory, e.g. a magnetic bubble memory or a semiconductor memory, can be.

This development is based on the idea that in itself a part the capacity of the memory could be allocated to in addition to that through PCM signals generated any additional information, e.g. names, in response and telephone number from the private and business area, to be saved additionally. The storage capacity necessary for such additional information is in comparison usually relatively small compared to the storage capacity for storing the response. For example, if you want a text with a maximum length of around one minute in such a memory by means of delta modulation at e.g.

If you store 16 kbit / s, you need a storage capacity of 120 Kbyte. You need 100 names with phone numbers with an average of 10 letters and 10 digits on the other hand, a total of only approx. 2 kbytes, i.e. around 2 O / o of the total storage capacity. That means that the recording time then usually by 2% is decreased. Especially if, however, the additional information stored are even more extensive and a reservation of much higher capacities this storage would be the maximum duration of the storable response must be reduced accordingly, that is to say considerably in the example described above must be shorter than that minute. Such a reduction in the duration of the stored Answer in favor of reserving storage space for additional information however, it is often very undesirable, especially when the capacity of the memory, e.g. due to lack of space in the housing of the telephone set, not selected correspondingly higher can be.

When the invention is applied to the telephone answering machine case described above However, it is possible to even reduce the response time despite saving to avoid the longer additional information entirely, even if the additional stored information in total e.g. 15%, i.e. e.g. every eighth bit of the Claim storage space for yourself.

Since with delta modulation up to 15 °, 4 of the stored answer without Significant disruption of the quality of the analog response reproduction can be falsified, it is possible to provide the additional information, e.g. about names and telephone numbers and possibly addresses, with the help of the special digits nested within the PCM signals, which correspond to the answer, and thus the full speaking time for the Answer, i.e. a full minute in the above example, is still available to have. Here, particularly few special digits are used to store the additional Information needed when the additional information concerned is a telex code or a similar code with little redundancy.

In the case of a magnetic bubble storage device, the additional information i.e. the special digits, e.g. save in very specific secondary loops, namely e.g. in every 8th or 16th secondary loop, whereby for saving this Special digits, non-defective secondary loops should be selected. Such Reservation of secondary loops for special digits within one for storage Magnetic bubble memory used by delta-modulated signals is therefore a special feature little effort involved, because it limits the maximum duration of the storable Answer not one. Also the control of this magnetic bubble memory for blanking the special digits is possible without much effort by using the magnetic bubble memory, which, as is well known, when reading the secondary loops by commands typical for it typical cycle times are controlled in the form of these typical commands time stamps which receives the sampling of those time channels which contain the special digits by counting the time channels or the corresponding clocks.

See, for example, the not previously published DE-OS 30 34 274 and 30 34 288.

If not at the same time, but first a first part, namely the additional information first or the delta-modulated answer first, and only later the other remainder is stored in the magnetic bubble memory, then the rest can be saved by typing the The remainder also reads the first part that has already been saved at the entrance of the write path of the magnetic bubble memory, the rest of the time channel and the first one that has just been read Part gradually overlaid, so the special digits in a time channel-appropriate manner nested with the digits of the PCM signal and these are stored in the input the write path of the magnetic Bubble accumulator enters. To this In this way, you can change the first part by writing the remainder into the Magnetic bubble accumulator avoided.

When saving the additional information or

Special digits can be used first for the answer and then for the information, and vice versa, store the information first and then the answer. if the answer is saved first, then in those memory locations or secondary loops, in which the special digits could later be saved, initially without further ado Save delta-modulated signal digits of the response. Only if then the additional information is to be saved there, then you can use the Overwrite the relevant memory locations or secondary loops with the special digits. Such an operation has the advantage that even the low noise or hum, which can be caused by special digits, only exists if really at the information has been overwritten - otherwise this part of the answer remains completely unchanged due to special digits.

With such a telephone answering machine, the microphone incoming analog signals are converted into PCM signals in an A / D converter and then serially, possibly superimposed with special digits, the write path of the magnetic bubble memory be forwarded for storage. When listening to the answer, the PCM signals In turn, read out serially via the read path without fading out the special digits and forwarded via a D / A converter to the loudspeaker of the response receiver.

The additional information, i.e. the special digits, can be used here e.g. via a telephone answering machine keypad, e.g. in one Telex code. You can also use this keyboard the control unit of the magnetic bubble memory are communicated that the hitherto stored first part is to be read at the same time or e.g. that under certain Addresses or certain information stored in certain time channels or Answer components can now be read. The control unit then does this corresponding readout from the magnetic bubble memory o This control unit can If necessary, the special digits can also be performed in a manner known per se the sequence of digits read from the magnetic bubble memory.

Such a magnetic bubble accumulator together with its control unit takes up so little space that in many cases it is easily possible to use these two To accommodate components within a telephone set with an additional keyboard. This has the additional advantage that the normal keyboard is often used as the keyboard of the telephone set can (also) use.

For the operation of such a telephone answering machine there are e.g. also the following option, which requires relatively few keys: The telephone keypad has only 12 buttons, for example. Assigns each key, in addition to e.g. one Number, two letters can be added, except for two letters (e.g. J, Q) Put all the essential letters of the alphabet on the keyboard. By an additional measure, e.g. by means of a correspondingly frequent actuation a special key (zero key) can be formed, it is pressed whether each the digit or the first letter or the second letter of a button is meant, which enables a clear assignment to letters and numbers will. Such an assignment is also possible through special sequences of key presses or also possible by entering special code words or code digits, e.g.

with the help of mnemonic codes. It is also possible to assign these letters to be reached by one or more additional buttons.

The main advantage of such an operation is that the Telephone answering machine with negligible additional effort an additional one Has a performance feature or an additional facility by in particular can also be used as a telephone directory. Also short numbers, automatic Dialing and call repetition, including other facilities, can be assisted Realize the additional information or special digits by adding these special digits the relevant abbreviated numbers, full numbers that can always be dialed automatically or represent other information. The magnetic bubble storage as storage at the same time for the PCM signals and for the information has in addition to the Most semiconductor memory types have the advantage that all of the information is stored and PCM signals are not lost if the power supply fails. Such a Telephone answering machine has the following advantages in particular: - A normal one Telephoning is possible - additional information can be provided via the telephone are additionally stored, - the reproduction of the additional information is basically both acoustically (speech synthesis) and optically (liquid crystal display) possible - the entry of names and phone numbers is variable in length about the keyboard possible, - Querying saved assignments of proper names and phone numbers is by entering the proper name or the phone number and by automatic comparison whether this proper name or phone number in the form of Special digits has already been saved, and queries such as the assigned phone number or proper name is possible with the help of simple AND elements - also the special digits can subsequently, if necessary, independently of the PCM signals, by renewed Overwriting can be deleted again; and calling using abbreviated numbers and others Facilities such as automatic dialing and repeat calls are made possible by the associated phone numbers are saved as special digits.

In the case of PCM records, the special digits S can e.g.

a spoken commentary on the respective music passages, and / or also show the plate manufacturer's code numbers, e.g. via the press date.

In the case of PCM television signals, the Soderdigits can e.g.

correspond to an on-screen text.

9 claims 3 figures

Claims (9)

Claims. 1. Method of operating a PCM system, in particular a PCM telephone switching system and PCM long-range transmission system, as well as for the operation of a PCM storing signals Memories, in particular a PCM telephone answering machine memory, a PCM video memory or a PCM record, in each case - the PCM signals of a sequence of analog signals - a small proportion (S), e.g. 1% or 15 O / o, of the PCM signal digits, each of which is regular and can be filled in with a large number of PCM signal digits Have time intervals (ts), are changed, i.e. represent impressed special digits (S), which, with regard to the PCM signals, have an impressed noise or an impressed - the special digits (S) represent additional digital information, whose transmission speed is low compared to the transmission speed PCM signal digits, and - when transferring between connections or when retrieving the PCM signals, the special digits (S) are treated like digits of the PCM signals, i.e. are not suppressed, but one or more connections or consumers, e.g. a loudspeaker or a screen, as superimposed noise or as superimposed disturbance can also be passed on, that is, it is not indicated e t that - the special digits (S) from any additional, from a connection information that can be entered by the user is generated - not just on the result the ana- log signals or markings related to the PCM signals not just markings e.g. for synchronization, for parity bits, for the start and / or the end of the PCM signals, or for the start and / or the Represent the end of a section of these PCM signals, and - if necessary, for themselves by blanking, i.e. by filtering out the unchanged PCM signal data Connection or one of the connections or consumers are fed independently of whether the PCM signals containing the special digits are also one at the same time the connections or consumers are fed or not. 2. The method according to claim 1, d a d u r c h g e k e n n z e i c h n e t that - the PCM signals through words (»yte), e.g. consisting of eight bits are formed, which is the difference in time between the respective analog signal value constant reference value, and - the special digits (S) at least significant Digits (N) within the words (bytes) are stamped (Fig. 1 and 2). 3. The method according to claim 1, d a d u r c h g e k e n n z e i c h n e t that - the PCM signals represent delta-modulated analog signals, that is the difference between the respective analog signal value and the previous one Value of the same analog signal (Fig. 3). 4. The method according to claim 3, d a d u r c h g e k e n n z e i c h n e t that - the PCM signals in a memory, e.g. magnetic bubble memory, a telephone answering machine. 5. Verfahr.en according to claim 3, d a d u r c h g e k e n n z e i c h n e t that - the information of the special digits by means of a keyboard the PCM signal is impressed and if necessary by blanking from the memory to a optical display unit. 6. The method according to claim 3, d a d u r c h g e.k e n n z e i c h n e t that - the phone numbers corresponding special digits for the automatic Calling, e.g. for call repetition, are used. 7. The method according to claim 3, 5 or 6, d a d u r c h g e k Note that - the special digits notes of the telephone answering machine owner represent. 8. The method according to claim 1, 2 or 3, d a d u r c h g e k It is noted that - the special digits stored on a PCM record (S) Show comments or notes on this plate. 9. The method according to claim 1, 2 or 3, d a d u r c h g e k It is noted that - the PCM image signals are imprinted with special digits (S) correspond to a written additional text.