NO157153B - DEVICE FOR FITTING WITH THERMOSTAT CONTROLLED MIXTURE VALVE FOR HOT WATER CONTAINERS OF PRESSURE TYPE. - Google Patents

Description

Time multiplex transmission facility.

This invention relates to a time-multiplex transmission system in which the fact that the occupancy time for a transmission channel in each of the two directions during a telephone call is less than half of the total conversation time is used, in order to increase the ratio between the number of connections made and the required frequency band width.

With the so-called speech interpolation systems (TASI)

it is already known to utilize the time during which the individual voice channels are not covered, to connect a number of n voice lines to a transmission device, which number n is greater than the number m of transmission channels available

disposition.

In such transmission systems, the connection takes place

of the voice lines to the transmission channels (which can be of any kind, mostly multiplex channels though)

over a so-called TASI device which only allocates a transmission channel for the individual voice lines during their coating. The TASI devices are thus completely independent of the multi-channel transmission system and only serve to switch the voice lines in the most appropriate way to the transmission channels. The costs of the TASI facility will therefore come

as a complete addition to the transmission facility in the total facility costs, so that the use of speech interpolation systems has so far only been economically acceptable for very expensive transmission paths, such as submarine cables.

With the invention stated in the present patent claim, this disadvantage is avoided.

The system according to the invention thus works on the basis of the same principle as the known speech interpolation systems, but using a full code demodulation3 device by which the coding of the signals arriving from the individual speech lines is interrupted when the line in question is not covered. As a result of this, the maximum number of lines to be sampled (samples) in a work cycle is in the vast majority of cases (over 999 °/oo of the conversation timej less than half the number of lines connected to the device. When thus the maximum number of samplings that can be carried out in one cycle is fixed equal to half the number of voice lines connected in the system, there is no reason to fear any appreciable degradation of the transmission quality. In such a case, the time required for completion of a scanning cycle equal to half the time that would be required if all connected wires were to be scanned in each cycle.

As the clock frequency for the sampling of the voice wires is fixed at 8000 samplings per second, i.e.

a scan lasts 125 microseconds, obviously by performing a smaller number of scans per cycle a longer time is available for each scan, and the duration of the individual pulses that are transmitted over the transmission path

can be chosen greater than by scanning all connected wires during each cycle regardless of the operating state. Since, on the other hand, the bandwidth required for the pulse transmission is inversely proportional to the pulse duration, by extending the pulses a saving occurs with regard to the bandwidth of the transmission path.

As the lines scanned during one cycle are not necessarily the same as in the previous cycle, additional information must of course be transmitted which makes it possible on the receiving side to distribute the coded information correctly to the associated outgoing lines. This information shall be referred to here as distribution information. For the transmission of this distribution information, in the present invention, a number of additional pulses are transmitted in each cycle which is equal to the number of connected voice lines. The number of pulses in a cycle is thus for a system with n wires, of which only n/2 are sampled during each cycle, equal to

8(^) + n+l=5n+li as opposed to (8n + 1) pulses which would be required if the scanning was done without regard to the coating of the scanned wires.

The percentage increase in the connections possible with a given frequency band (or at the same connection speed of the components included in the system) is thus equal to

As will be further explained in more detail below-

for, the invention thus solves the problem of utilizing the unoccupied time for a certain number of telephone voice connections in both directions for saving bandwidth or increasing the number of possible voice connections, without having to connect a TASI device between the voice lines and the transmission channels, as pulse modulation devices with suitable modification and operation are used.

Compared to a conventional PCM system up-

there is admittedly a certain increase in equipment or device costs per voice line, but on the other hand the common equipment (for coding, decoding, timing, line pulse amplifier

ing etc.) are utilized by a larger number of call connections.

The costs per voice line are therefore not significantly higher, so that the use of such systems is also economically advantageous on shorter distances.

In the case of systems where the speech breaks are used for

to provide additional voice connections, as is known, the highest degree of efficiency is achieved when echo blockers are switched on, which prevent the received signals, due to imperfect balance in the necessary fork connections for connecting two-wire lines, again appearing on the sending side and covering the channel for this direction of transmission, which is then in reality free . Of course, such an echo barrier makes a simultaneous transmission in both directions impossible.

With the help of the present invention, a mode of operation is realized which functionally corresponds to switching on an echo barrier and thus prevents a simultaneous transmission in both transmission directions. As mentioned, with the present system provision has been made for an interruption of the coding for such voice lines which, during a period of time longer than a certain value, are uncharged. In addition, a device described below ensures that a number of voice line signals are coded in each scanning cycle, which number is, for example, equal to or less than half the number of all voice lines connected to the system, and that signal coding of as many new lines is carried out in each cycle, as there are wires at hand, if coding had been interrupted because these were found not coated, if in each scanning cycle one would only scan the wires whose signals are to be applied to the encoder, then the subsequent de- keyings of a specific wire do not occur at constant time intervals. It is obvious that every time the scanning of some lines is carried out or interrupted between one cycle and the next, random extensions or shortening of the time interval will take place, the already running scans following each other.

In order to avoid this, it is ensured that the sampling of all speech lines is carried out in all sampling cycles and at the same time. The scan values thus formed are stored in special storage capacitors. During subsequent scanning, only signals from the storage capacitors belonging to the lines to be coded are sent to the coding device. The received and decoded sig-

nals are stored in corresponding capacitors by means of a distribution similar to the scanning carried out on the sending side. At the end of a sampling cycle, all capacitors simultaneously transmit their sampling values to the associated speech lines.

The invention will be explained in more detail in the following with the help of the drawings, of which

figure 1 shows a diagram of a terminal equipment for

a multiplex transmission facility made according to the invention and

figure 2 shows a diagram of transmitted pulse trains for further explanation of the invention.

The device shown in Figure 1 essentially contains the following units:

Distribution chain.

There are two distribution chains CDel... CDen

and CDrl...CDrn, the first of which is assigned to the sending side and the second to the receiving side. These distribution chains are designed in a similar way to normal PCM systems, with the exception that an electronic switch CEel...CEen or CErl...CErn is arranged between the individual steps in the chain, which, depending on the switching position, bypasses or does not bypass the following steps.

The operation of the conventional distribution chain

is known so that a brief explanation should suffice. All steps in a chain simultaneously receive forwarding pulses which, in the present case, are supplied to the sending-side chain over a wire b and the receiving-side chain over a wire e. However, only the steps that have received a release signal from a previous step react to these forwarding pulses. In order to start a chain, there is therefore a starting circuit AVVe and AVVr respectively arranged in this way, which are controlled by synchronization signals arriving over the wires a and g respectively, and deliver the release signal for the first step in the associated chain. Each speech line 1LN...nLN

is assigned to a distribution chain step. The electronic switches connected in the chains CEel...CEen respectively CErl...

CErn allows the disconnection of an arbitrary number of stages from the chain, whereby it is prevented that the sampling values stored in the storage capacitors MCel...MCen on the transmitter, which come from speech lines assigned to disconnected stages, are supplied to the coding device.

The operation of the distribution chain at the recipient

side corresponds to the operation of the distribution chain on the sending side. On the sending side, the distribution chain controls encoding ports PCI...

The PC whereby only such ports are activated which belong to the cables to be connected. Correspondingly, the distribution chain on the receiver side controls associated storage ports PMl...PMn which lead the coded signal sampling values to storage capacitors MCrl...MCrn assigned to corresponding voice lines. The electronic switches for the distribution chain on the transmission circuit

and the receiver side is controlled by corresponding switch-on storage devices.

Plug-in storage devices.

In the case of a system which does not enable simultaneous transmission of the telephone signals in both directions, one would come up with a single switch-on storage device for sending and receiving, but in the present embodiment of the invention, separate bistable switch-on storage devices Mrl... Mrn and Mel...But for the receiving side and the sending side respectively. ' Each step in the respective distribution chains is assigned a bistable storage connection. As the tasks for the storage link on the sending side and the storage link on the receiving side are somewhat different, they are explained separately in the following.

The storage link or circuit on the sending side performs with its output signals a fourfold function: a) It sets the electronic switches CEl...CEen in the distribution chain on the sending side; b) It gives at the output an indication of whether a particular wire is connected or not, in order to control the formation

of a distribution information which is produced by means of a coupling device which is not produced here, then

it is not necessary for the understanding of this invention;

c) It provides an inhibit signal to AND circuits from scan ports PCArl...PCArn on the transmit side, which signal prevents a wire from being scanned on the transmit side

which is scanned on the recipient side, and

d) it sets electronic switches CEl...CEn in a preparation chain CPl...CPn so as to effect bypassing of the preparation elements belonging to lines already connected for coding on the sending side.

The individual storage circuits are subjected to a dual control, namely by means of a switch-on and release signal. The switch-on signal serves to switch on a specific storage stage. When a step has been switched on, this means that the associated electronic switch is set so that the signal from the associated wire is coded. The assert signal causes the release or release of the storage stage to which it is pressed. By "releasing a storage step" is meant here that the relevant step is set so that the voice line corresponding to the assigned distribution step is omitted from the scanning cycle.

On the receiving side, the storage stages Mrl... Mm each perform a threefold task: a) They set the electronic switches CEl...CEn in the distributor on the receiving side; b) They issue a blocking signal to AND circuits from scanning ports PCAel...PCAen on the transmitting side, which signal prevents a wire being scanned on the transmitting side that is scanned on the receiving side; c) They set the electronic switches CEl...CEn in a preparation chain CPl...CPn so that bypassing of the preparation elements belonging to lines already connected for storage on the receiver side is effected.

Pore preparation chain and time coin side circuits.

The preparation or presetting chain CP1...CPn is normally constructed with bistable circuits which are connected between the electronic switches CEl...CEn, to enable an optional bypass of the bistable circuits.

Each bistable circuit controls a bistable storage circuit Mel...But on the sending side, whereby connection of the associated lines is made or not made. The n steps in the chain are connected to a closed ring. Forwarding of the chain is controlled using output pulses from a gate circuit B, which will be explained in more detail below. At each connection step in the preparation chain, a voice line is connected. As will be further explained in more detail below, the number of steps per cycle is chosen such that in the present example, the number of connected lines in each cycle is equal to or less than half the number of all voice lines present. The release of the wires is in turn controlled by a release pulse that is common to all wires, but blocked for all the wires in which a signal occurs that exceeds a certain threshold value. Of course, not all wires that are switched on in one cycle are in reality coated, but the uncoated and unwanted switched-on wires are then disconnected or excluded in the following cycle, as the above-mentioned blocking will be missing. A time coincidence circuit CTl...CTn is assigned to each voice line. These circuits are controlled in two ways: One control is common to all circuits and takes place with the help of a threshold value or trigger circuit SG, which will be explained further below. Every time there is a signal in a wire which is connected for coding, and the signal exceeds the threshold value, an output pulse is produced which simultaneously activates all time coin side circuits. However, a further signal is also fed to the time coincidence circuits from one assigned coding port PCI...PCn, which signal occurs when this port is closed. Therefore, only the time coincidence circuit that belongs to the line from which the signal that exceeds the threshold value originates is activated

When a time coin side circuit is activated, it emits a signal at the output which blocks the *release signal for the associated wire. However, if the time-coincidence circuit is not activated because the wire is not coated and the threshold value circuit has not been affected, then the output signal from the time-coincidence circuit falls with a time constant adjustable between zero and an arbitrary value, to a value at which an assigned release AND gate ELI ...ELn emits a blocking voltage. When the release signal occurs, the relevant line is thus released in the desired manner.

Pricing AND gate.

A release AND gate ELI...ELn is assigned to each speech

line and performs the following logical function: Pricing

the signal is released or blocked depending on whether there is a blocking signal from the time coincidence circuits or not.

Sampling Gate Circuits and Sampling AND Stages.

For each voice line, a scanning port PCAel...PCAen is assigned on the sending side and a scanning port on the receiving side

port PCArl...POArn. The scanning port on the sending side has the task at the time of scanning to convey energy from a line filter PLl...FLn to the corresponding storage capacitor MCel ...MCen on the sending side. As mentioned, sampling takes place simultaneously for all voice lines. However, the scanning ports PCArl...PCArn on the receiver side have the task of discharging the storage capacitors MCrl...MCrn on the receiver side at the time of scanning on the receiver side, which likewise occurs simultaneously for all speech lines, which discharge occurs corresponding to the line filter PLI...PLn.

The scanning ports on the transmitting side are controlled by associated scanning AND stages which are controlled in such a way by sending and receiving respectively receiver connection storage devices, that the scanning of connected voice lines on the sending side during reception and the scanning of connected voice lines on the receiving side during transmission is blocked.

Threshold circuit SG.

This threshold circuit SG is designed in the usual way and is switched from a zero state to a one state when input

the signal exceeds a certain threshold value. The input of the threshold circuit is connected to the encoder input (wire c)

and examines the amplitude modulated pulses coming from the encoding ports. As mentioned, the output signal from the threshold value circuit controls the time coincidence links or circuits.

Figure 2 shows an example of a pulse train like this

as it is transferred by a plant according to the invention over a transmission path. The number of connected voice lines is assumed to be equal to n, while the largest number of encodings that are transmitted over the transmission path must be equal to m = n/2.

After an initial synchronization pulse Sinl becomes

it transmitted a distribution information MD. This information can be structured according to an arbitrary rule, which must of course be the same on the sending side and the receiving side.

In the embodiment shown in Figure 2, the distribution information consists of n pulses, i.e. as many pulses as there are associated voice lines in the system. The polarity of these pulses indicates whether the associated voice line should be switched on or not. Pulse one is sent in such order that the first pulse corresponds to the first speech line, the second pulse to the second speech line, etc.

After the distribution information MD follow normal groups Cod.l to Cod.M of each eight pulses for each coded sampling value, of which seven are intended for the coding and the eighth pulse Sel...Sen is intended for signaling purposes.

It is clear that the signaling pulses are independent of the distribution process, i.e. of the coding of the speech signals to which they are assigned.

The signaling pulses are transmitted in a fixed order for all n voice lines, regardless of whether these are switched on for coding or switched off.

In the example shown in Figure 2, where it is assumed for the sake of simplicity that m = n/2, the signaling pulses Sel...Sen cover two consecutive cycles.

Furthermore, under the assumption that m = n/2 is the number

of pulse groups Cod.l...Cod.m equal to or less than half the number of all voice lines connected to the system. The information which designates the various voice lines whose signals are actually coded in a particular cycle is sent in sequence over a wire cl to the coding device and then transferred over the transmission path. When in a certain cycle, for example, the signals in lines 1, 3, 5 and 6 are coded, these lines' associated codes are also sent in the same order. As mentioned, the switch-on-storage device on the sending side determines with the help of the electronic switches which wires whose sampling values are to be coded in a specific cycle. In the example shown, the state of this storage device step corresponds as a whole to the distribution information delivered to the transmission path, and the formation of this information is controlled by the same switch-on storage device

on the sending side above the outputs in l...in.

Assume that in a given cycle signals from p lines are coded (p<m): The system's logic is designed so that a series of m pulses is produced for sampling the sampling values stored in the storage capacitors. After the scanning of the p coding gates, the p-th pulse is thus obviously delivered either directly from the nth step in the distribution chain or from electronic switches which, with the help of the associated switch-on storage devices, are brought into bypass or pass-through position. With its trailing edge, this pulse sets a bistable circuit A (figure 1) in a position where a gate B is opened, through which the other (m - p) pulses can be forwarded so that the preparation chain is forwarded with (n - p) steps . After this redirection, the chain remains until the next cycle in the achieved position and then begins the redirection in the same way again. The leading edge of the mentioned pulse, on the other hand, gives the release pulse which - as mentioned - causes the release of the wires for which the time coincidence circuit has been de-energized. This happens before the forwarding of the preparation chain. The bistable circuit A is again returned to its resting state by means of synchronizing pulses. As mentioned, from the preparation chain all such steps are disconnected which are connected on the sending side and/or the receiving side. This happens with the help of the electronic switches arranged between the steps of the chain.

The m - p pulses thus cause switching on the sending side

a corresponding number of wires which at this moment are definitely not connected in either direction. From the above explanations, it is clear that the total number of wires that are connected in the individual cycles can never be greater than m. Of the m - p connected wires, some or all of them may be unbiased on the sending side, but in this case the associated time-coincidence circuit becomes not activated by the threshold circuit, and the release pulse in the next cycle will cause release of these leads.

It has already been mentioned that on the sending side all lines that are not connected on the receiving side are also sampled at the same time as the synchronization pulse. The thereby obtained sampling values are stored in the corresponding storage capacitors and then a part of it is passed on for coding. On the receiving side, the switch-on storage device assumes in each cycle the state that corresponds to the distribution information that comes from the corresponding terminal. The device for receiving and passing on the indications contained in the distribution information is not shown in figure 1 as this is not essential for understanding the invention. This device is connected via wires hl...hn to the steps in the switch-on-storage device on the receiver side.

The electronic switches are thus prepared

in such a way that each signal coming from the decoding device over a wire f through the storage port charges the corresponding storage capacitor. At the same time as the synchronization pulse, all stored sampling values are likewise supplied to the associated line filters through the sampling ports on the receiver side. In this connection, it should be mentioned that in the respective cycles the ports for such lines which are connected on the sending side are not activated.

For sending and receiving, the present device only requires a single line filter: the 0G connections on the sending side and the receiving side, which are controlled by the receiving and sending-storage devices respectively, ensure that a filter can only be connected to the transmitting circuit when it is not connected to the receiving circuit and vice versa . The blocking on the transmitting side of the switching on of channels which are connected on the receiving side and the function of the scanning ports on the transmitting side and the receiving side make it impossible for a received signal to be transmitted again. This makes the use of an echo barrier and a fork coupling redundant.

Claims (4)

1. Time multiplex transmission system for telephone voice signals which are transmitted on n voice lines each of which may be coated or uncoated, with a multiplex transmission device comprising a number of transmission channels m which is less than n, to which channels in a sampling cycle is assigned to sampling values and where further each transmission channel corresponds to a specific time period for transmission of a speech signal, and with a coding device for the sampling values, characterized in that a group of gate circuits (PCAel...PCAen) which above the low-pass filter (Fll...FLn) is connected to the speech lines (1LN...nLK), on the transmitting side performs a simultaneous sampling of the speech signals for all coated and uncoated lines that are not also sampled in the same sampling cycle on the receiving side, during which such a double sampling is prevented by AND gates that are affected of a sampling synchronization pulse and the speech line condition on the receiver side, that the sampling values of the speech line The gsigfcials are stored in storage devices (MCE1... MCEn) intii<;>~~gate circuits (PCl...PCn) in sequence are affected and connect the storage devices with the wire (cl) which transmits the sampling values from the coding device and which in turn is controlled by a distribution chain consisting of trigger circuits ( CDel...CDen) which at the same time is controlled with periodic pulses and successively emits influence pulses for the gate circuits and which are further assigned to storage circuits (MEI...But) which cause activation of the trigger circuits which correspond to the coated speech lines and thus the gate circuits , during which the coating condition is determined by means of a threshold circuit (SG) which is affected by the sampling the values and emits a corresponding signal to the storage circuits, which signal disengages the trigger circuits from the distribution chain corresponding to the voice lines which have been coated and released so far and remains in this state for a time shorter than the time determined by time coincidence circuits (CTl . which information consists of a series of pulses which, with their time position, correspond to the voice lines and indicate whether the line in question is to be considered coated or uncoated, that a line (f) is arranged on the receiver side for the transmission of the sampling values that come from the opposite terminal through the decoding device and through a group of gate circuits (PMl...PMn) are successively connected to capacitor-storage devices (MCrl...MCrn) which on their s ide is connected to the gate circuits (PCArl...PCArn) which are connected to the corresponding speech lines, of which gate circuits are simultaneously activated at a constant rate only those which connect the capacitor-storage device with the speech lines (lLN...nLN) over the filters (PLl. ..PLn) and which are not affected on the transmit side in the same sampling cycle, during which the activation of the other circuits is prevented by means of AND gates which are affected by the activation pulse of the gates and the condition of the wires on the transmit side, and that a number of storage circuits (Mrl . circuits (CDrl...CDrn). 2. Plant according to claim 1 characterized in that the distribution chain on the sending side consisting of trigger circuits (CDel...CDen) has a number of electronic switches (CEel...CEen) which is connected between the trigger circuits and is controlled by the send-storage circuits (Mel...Men) and which excludes or disconnects from the distribution chain the trigger circuits assigned to the bare telephone lines, and that the distribution chain on the receiver side, which also consists of trigger circuits (CDrl...CDrn), includes a number of electronic switches (CErl...CErn) which are connected between the trigger circuits and are controlled by receiver storage circuits (Mrl... Mrn). 3. Installation according to claim 1 or 2, characterized in that a ring-preparation chain consisting of trigger circuits (CPl...COn) between which electronic switches (CEl...CEn) are arranged, tests the uncoated voice lines and prepares the corresponding ports (PCl...PCn) for passing through the sampling values of the line signals for coding and transmission upon occurrence of the sampling values, during which such trigger circuits are switched off by the preparation chain of the switches, corresponding to voice lines determined as covered by the storage circuits (Mel ...But) on the sending side, and that the preparation chain for testing the uncoated voice lines in each scanning cycle is forwarded as many steps as correspond to the difference between the number of available channels and the number of channels that are actually coated during transmission" 4. Installation according to one of claims 1 to 3, characterized in that the sensing of the coating state of the voice lines whose signal sensing values are provided for transmission is carried out by means of a single threshold circuit (SG) whose input is connected to the transmission line (c) and whose output leads to the inputs on time coincidences (CT1...CTn), whose further inputs the signals from the trigger circuits (CDel...CDen) in the distribution chain on the sending side occur and whose outputs lead to the inputs on coincidence circuits (ELl...ELn) which on the additional inputs receives the signal coming from the last trigger circuit (CD) in the distribution chain and which deletes the storage circuits (Mel...But) on the transmit side when the threshold circuit (SG) exhibits sampling values on the transmit line that remain less than the threshold value for a period of time which is longer than the time determined by the time coincidence circuits (ZT1 ZTn).