DE1084310B - Expandable encoder - Google Patents

Description

Expandable encoder for the transmission of pulse-coded Messages sometimes encounter a transcoding problem. This is for example in telex technology when changing from the normal 5-digit code to a 7-digit security code the case. Such a security code is preferably structured equally, d. that is, the number of separating stream steps or character stream steps of each complete Code character is constant if there are no errors. Such a code that consists of a code elements exists, each of which b has a certain polarity (e.g. character polarity), is referred to as the "b-of-a-code".

There are coding circuits known that such a code conversion accomplish with a minimum of switching elements (directional ladders).

The code conversion problem occurs wherever 1 out of n messages is to be transmitted, e.g. B. in remote control systems, in which case there is a requirement to convert a 1-of-n code into a k-of-m code. In order to keep the product of transmission time and bandwidth as small as possible, the number m of code elements must be a minimum for a given n. This leads to the easily verifiable condition that have to be. This results in z. B. with m = 6, 7, 8, 9; 10 code elements are assigned the maximum number n of possible combinations A coding which converts the code 1-of-n into a code k-of-m can be set up in a known manner according to the example shown in FIG. As an example, a conversion of the code 1-of-20 to the code 3-of-6 is shown. When a switch in the switch group S is actuated, three of the six output lines K1 to K6 are excited via three corresponding directional conductors in the directional group Gr.

Since, depending on the application, such a transmission system for 1 of n messages can have a very different n, a must be accordingly The built-in coder can be easily expanded to suit the respective operating conditions to be able to be adapted. In addition, for capital n is the splitting of a directional ladder built-up encoder in smaller units to be connected in series required, because with direct coding the output lines of such an encoder would via a large number of parallel blocking resistances between the decoupling directional conductors be connected and an operationally safe working of the arrangement under certain circumstances too strong coupling can no longer be guaranteed.

The invention relates to an encoder, which is characterized by easy expandability, high operational reliability and economic structure. To illustrate and explain the invention, the following terms are used below: n = number of code elements of the to be converted Codes; a = number of people who confess in a certain way drew code elements of the to be converted Codes; m = number of code elements of the code to be formed; k = number of professing in a certain way. drew code elements of the code to be formed; m, = number of code elements of the so-called Basic coding units (see later explanations tion) ka = number of identified in a certain way marked code elements of the basic coding units; a = 0, 1,. . . (mm,). The coder according to the invention for forming the k-of-m code from an a-of-n code, in particular for large n and small a, preferably for a = 1, is characterized in that the coder according to the addition law of Binomial coefficients are made up of small, easily realizable basic coding units that can be built up in a manner known per se, each with mr code elements (m, units), the number m of code elements of these basic units being smaller than the number m of code elements of the code to be formed, and that these basic units or higher-order coding units formed from them are interconnected in pairs via decoupling circuits to form coding units of the next higher number of code elements.

The formation of these basic units according to the addition law of the binomial coefficients is explained below using an example that shows the formation of a k-of-m code from a 1 = of-n code (a = 1).

According to the law of addition of the binomial coefficients, with mr = E- y = m or advertised These basic units (mr units) are connected in pairs via decoupling circuits to the next higher coding units according to the relationship summarized. According to a further development of the invention, these decoupling circuits are designed so that to convert a code with a total of P code elements (P <m) and q + -l code elements (q + 1-von-p = code) identified therefrom into the code of the next higher order with P -f- 1 code elements and q + 1 identified code elements (q + 1-of-p -j- 1 code) all P outputs of the q + 1-of -p coding unit directly to p outputs of q + 1 -von-p -E- 1 coding unit are switched and that, furthermore, to convert the code corresponding to the aforementioned law of addition with p code elements and q code elements (q-von-p-code) into the q + 1-vonp + 1- Code all P outputs of the q-of-p unit via appropriately polarized directional conductors to the same p outputs and all P outputs or at least Pq -i-1 outputs of the q-of-p unit via appropriately polarized directional conductors together to the still free Output of the q + 1-of-p - [- 1 coding unit are switched.

For reasons of consistency, it is advantageous to use all decoupling circuits to be built up in the same way; and with the maximum number 2 - (m-1) of the required guide to interpret.

The invention will be further explained using an example: FIG. 2 shows an encoder constructed in accordance with the invention for converting the 1-of-252 code into the 5-of-10 code. A coding unit with six code elements was chosen as the basic unit (mr unit). Inserting these values into equation (1), the number of different types of m, units and the number of m, units of each type result from the following relationship: So you get 17nr units for the code 5-of-6, 4 mr-units for the code 4-of-6,. 6 mr units for the code 3-of-6, 4 m, -units for the code 2-of-6, 1 m, -unit for the code 1-of-6.

The number of different types of m, units is always equal to the number of terms in equation (1). In the example chosen, this number is five. In general, when converting a 1-of-n code into a k-of-m code and when forming basic units with mr code elements, this number is mrmr + 1. The number of m, units of a certain type required then results from the corresponding coefficient of equation (1).

The m, units represented by rectangles in FIG. 2, each with six code elements, are in principle constructed in a known manner according to FIG. 1, but equipped differently according to the number of identified code elements (1 ... 5). These mr units with six code elements are combined in pairs to form coding units with seven code elements. These newly acquired coding units, each with seven code elements, are combined again in pairs to form coding units with eight code elements, these again in pairs to form coding units with nine code elements, and these finally to form the final unit for the 5-of-10 code. The combination takes place via decoupling circuits, which are represented by circles in FIG. 2: The structure of such a decoupling circuit is shown in FIG. of-8 code according to the relationship shown. In the transition from the 4-of-7 code to the 4-of-8 code, the number of code elements identified in a certain way (e.g. character stream steps) remains the same. In terms of circuitry, this can be achieved most easily if the structure of the particular combination of the 4-of-7 code is retained unchanged and only at certain, e.g. B. an unmarked code element (e.g. separating current step) is added to the last digit. In the circuit shown, all seven inputs E "1 to E" 7 connected to the outputs of the preceding unit for the 4-of-7 code are therefore directly connected to seven outputs A 1 to A 7 of the unit for the 4-of-8 Code switched. The eighth output A 8 of the 4-of-8 code unit therefore always remains primed in this case and supplies an unmarked code element (isolating current step).

In the transition from the 3-of-7 code to the 4-of-8 code, on the other hand, a marked code element (character stream step) must be added. In terms of circuitry, this is achieved in that all seven inputs E'1 to E'7 connected to the outputs of the preceding unit for the 3-of-7 code are connected to the aforementioned seven outputs A 1 to A 7 of FIG -von-8 coding unit are switched. In addition, however, all seven inputs E'1 to E'7 connected to the outputs of the unit for the 3-of-7 code are connected to the free eighth output A 8 of the unit for the 4-of-8 code via appropriately polarized directional conductor Grr 1. Code switched. The output A8 is therefore always also excited when a 3-of-7 code combination is present at the inputs E'1 to E'7 and thus supplies a marked code element (character stream step). To always mitzuerregen the output A8, it is not necessary to connect all seven inputs E 'l to about E'7 appropriately poled crystal diode on the output A 8th In the example shown, any two of these connecting lines can be omitted, that is to say two directional conductors can be saved, because at least one identified code element (character stream step) is still present on the remaining five connecting lines. In an analogous manner, directional conductors can be saved in all decoupling circuits, because at least one identified code element still occurs on P-q + 1 connecting lines.

For reasons of consistency, however, it is advisable to use all decoupling circuits with the maximum number of 2 # (m -1) guides required, d. H. in the chosen Example with 18 directional ladders each.

The encoder according to the invention is characterized by easy expandability, high operational reliability and economic structure. The easy expandability results from the division into smaller basic units (mT units) and their combination in pairs via simple decoupling circuits, which are expediently constructed identically to each other with only little additional effort, to form the next higher units. The encoder shown in FIG. 2, for example, can be used from n = 6 to n = 252 (1-of-6 to 5-of-10). The high operational reliability is given by the reduced number of blocking resistors in parallel compared to the direct coding and the better decoupling that can be achieved with it. The economy results from the lower number of guide guides required compared to direct coding. This is explained using an example. If the 1-out-of-252 code is directly encoded into the 5-out-of-10 code, 5 - 252 = 1260 directional guides are required. The number of directional conductors in the encoder according to FIG. 2 constructed according to the invention is only 958. If, for reasons of uniformity, all decoupling circuits are constructed identically (each with 18 diodes), 1026 directional conductors are required. This still means a saving of 234 directional guides, ie more than 200 /, compared to direct coding.

The arrangement hitherto described as an encoder can be used without any change can also be used as a decoder. In a manner analogous to that shown in FIG Coders can be coders for conversion without departing from the scope of the invention build any code into any other code. In any case the advantages and improvements shown can thereby be achieved.

Claims (3)

PATENT CLAIMS: 1. Extensible coder for forming a k-of-m code from an a-of-n code, in particular for large n and small a, preferably for a = 1, characterized in that the coder according to the addition law of Binomial coefficients from small, easily realizable basic coding units that can be built up in a manner known per se, each with m 1. Code elements (m, units) is constructed, the number m,. of the code elements of these basic units is smaller than the number m of code elements of the code to be formed, and that these basic units or higher-order coding units formed from them are connected in pairs via decoupling circuits to form coding units of the next higher number of code elements. 2. Encoder according to claim 1, characterized in that the decoupling circuits for combining the basic units in pairs or of higher-order coding units formed from them to coding units of the next higher number of code elements are constructed so that to transfer a code with a total of P code elements (P <m ) and q -E- 1 of which code elements marked in a certain way (q + 1-of - P code) into the code of the next higher order with P + 1 code elements and q + 1 code elements marked in a certain way (q -i- 1-of-p-f- 1 code) all P outputs of the q + 1-of-p coding unit directly to p outputs (A 1 to A 7) of the q -f- 1-of-p + 1 coding unit are switched, and that also for the conversion of the code corresponding to the aforementioned law of addition with P code elements and q code elements (q-of-p-code) marked in a certain way into the q +. 1-von-p + 1-Code all P outputs of the q-von-p-unit via appropriately polarized directional conductors (Gr2) to the same P-outputs and all P-outputs or at least Pq -E- 1 outputs of the q-von-p-unit appropriately polarized directional conductors (Gy1) are connected together to the still free output (A8) of the q + 1-of-1 coding unit. 3. Encoder according to claim 2, characterized in that all decoupling circuits similarly structured and with the maximum number of 2 - (m-1) of the required guide are designed.