A heat pipe heat exchanger for transferring heat from a high temperature fluid such as, for example, exhaust gas of a boiler, to a low temperature fluid comprises a first flow path (13,14,15,16,17) along which the high temperature fluid flows, a second flow path (18,19,20,21,22) along which the low temperature fluid flows, and a rotor (28) formed by a plurality of heat pipes (8) disposed across the two flow paths with such intervals that the high temperature fluid or the low temperature fluid ca...

The amount of money which should be charged upon reception of a pay television signal or a like information signal, is calculated by a charging device comprising a calculator (25) for calculating the amount of charge and an encoder (28) for encoding the charge and time instant (date) using by a key code specific to the charging device to form a check code which should be reported together with the charge. The date data may be indicated either by a timepiece (26) or by a time signal multiplexed o...

A key distribution method and system for distributing a key over an insecure communication channel between first and second systems. Both first and second systems generate respective random numbers, calculate key distribution codes based on that random number, public information and information secret to the respective systems, and transmits the distribution codes to the other system. The same key is generated by both systems based on public information, the locally generated random number and t...

In digital communications, a multi-mode block-coded modulation/demodulation method carries out adaptive one-way transmission of a multi-mode digital signal by using, between at least two different modes, different settings for level number, level code, set-partitioning method and modulation method that are component elements of a multi-level block-coded modulation system.

A transmission method with compensation for fading distortion or frequency offset distortion in digital communications using pilot signals, comprises the steps of: receiving modulated radiofrequency signals, demodulating the digital signals carried by said radiofrequency signals, extracting pilot signals from the received radiofrequency signals or demodulated digital signals, finding a spectrum of the extracted pilot signals, finding fading components or frequency-offset components from said spe...

A fuel injection valve has only one set of coil and armature to control both of the amount of fuel and the injection of fuel from the injection nozzle.

A data converter applicable to data communications protects messages against errors and modifications by a third party. What is required for the detection of errors and modifications is simply causing a transmit station to add a particular pattern and a receive station to detect the particular pattern.

A cryptographic system comprises a modulo-2 adder having a first input receptive of a sequence of binary digits to be scrambled and a second input receptive of a sequence of scrambling binary digits for generating a sequence of scrambled binary digits. A function generator having a memory is provided for storing a predeterminable sequence of binary digits in addressible storage locations and reading the stored binary digits in response to an address code represented by combined first and second ...

An enciphering key distribution system comprises a transmitter having an address generator for generating the addresses of those subscribers to which a first enciphered TV signal is to be distributed. An enciphering generator generates a second enciphering, in response to the individual addresses, on a one-to-one correspondence with the individual subscribers. A multiplier produces a product which is associated with all the subscribers. An adder adds the first enciphered signal to the product. T...

The invention provides separating agents for optical isomers which have a high optical resolving power inherent in polysaccharide derivatives and high solvent resistance, and which can be produced through short process steps; a process for producing the same, and a method for separating optical isomers. The invention also provides separating agents for optical isomers, wherein the surface of a polysaccharide derivative supported on a carrier or the surface of a pulverized or granulated polysacch...