RU2012027C1 - Method for multichannel measuring of time moments of recorded events and device for implementation of said method - Google Patents

Abstract

FIELD: measuring devices. SUBSTANCE: device has AND gate, clock, clock pulse counter, commutator, request generator, vernier generator, shaper of "reset" signals, counter of events, decoder, shaper of "start-stop" signals, three vernier counters, shaper of "record" signals, three registers of memory gate. EFFECT: increased functional capabilities. 2 cl, 1 dwg, 1 tbl

Description

 The invention relates to physics, in particular to a method for measuring moments of time of registration of events in nuclear-physical and astrophysical experiments.

A method and apparatus for multichannel measurement of time intervals between recorded events is widespread in a nuclear physics experiment (A. Tsitovich, Nuclear Radio Electronics. Moscow: Nauka, 1967, p. 288). Sequential measurement of time intervals between each neighboring event recorded on N independent channels leads to the need to organize N ² channels for sorting time intervals. Moreover, each time interval is measured with a certain accuracy, and when they are summed up, the accuracy of fixing the current time is lost. The equipment for the direct measurement of time intervals turns out to be complicated; it is difficult to increase the number of channels for the arrival of events.

 The closest technical solution is the method of directly measuring the time of arrival of events on N independent channels (Pimonov A. A. Photon Counting System. Messages Special Astrophysical Observer, 1979, N 25, p. 31). This method gives a gain in the number of necessary channels by a factor of N, ensures constant measurement accuracy of the current time throughout the entire measurement cycle. In this case, the time intervals between the registered events can be easily determined during further mathematical processing of the initial data array. The method is based on the fact that at the moment of an impulse from a registered event, the current state of the binary clock and the channel number on which the events were received are recorded in a storage device, from where then the accumulated data is transferred to a computer for further mathematical processing.

 The known device, selected as a prototype, contains a master oscillator, a binary clock, a storage device and a control unit. A disadvantage of the known method and device is that they do not provide scheduling of input and output streams, i.e., when the number of received events exceeds the number of memory cells during the data transfer to the computer, the loss of previously recorded events occurs and this fact is not recorded anywhere, which leads to the appearance of fatal distortions of statistical results. In addition, sequential reading from one counter without interruptions into the device memory leads to difficulties in achieving high temporal resolution due to the impossibility of avoiding reading information at the moments of change in counter states.

 The aim of the invention is the measurement of time instants of recorded events arriving on many parallel channels with high time resolution and accuracy over a long interval.

 The goal is achieved by the fact that the method described is based on the principle of vernier measurements, in which two scales are used to obtain high resolution and measurement accuracy over an extended time interval. One is the main one, providing measurement over a long interval, but with a rough division price.

 The second is vernier, providing high resolution and measurement accuracy for a short interval between adjacent divisions of the main scale. The combination of two scales allows you to solve the problem.

 In the device, the goal is achieved in that the main time stamp scale, hereinafter referred to as the clock, is formed by a low-frequency clock, to which the clock counter is connected. The vernier time stamp scale is formed by a high-frequency vernier generator. Choosing the frequency of the vernier generator, a multiple of the clock, we get a combined scale of time stamps.

 A comparative analysis of the described solutions with the prototype shows that the method differs from the prototype in that a vernier time stamp is formed by a high-frequency vernier generator, from the output of which pulse markers arrive in parallel to the counting inputs of several nonius counters. Before the start of measurement, all nonius counters are simultaneously reset and the count of nonius time stamps starts, and upon registration of incoming events, the nonius counters are stopped one by one, which makes it possible to measure the time moments of arrival of all events, starting from the specified "zero". The number of events for which recording times between adjacent clock ticks can be measured is limited by the number of nonius counters. The interval between two adjacent vernier marks defines the time resolution, and between the nonius tap marks determines the temporal resolution, and between the beat determines the duration (measure) of the measurement of vernier counters. The measurement accuracy is determined by the stability of the frequencies of the vernier and clock oscillators. Before the start of the whole measurement process, the clock counter is reset, which then counts the clock marks, and the readings are taken and transmitted to the computer from both the clock and nonius meters at the end of each measurement clock.

 A comparison of the described technical solutions with the prototype allows us to conclude that they meet the criterion of "novelty." Technical solutions are known in which the time moments of events are measured, but it was not possible to avoid reading information at the moments when the counter states changed. This is achieved in the described technical solutions and it becomes possible to record the total number of events received during each clock cycle. In the study of other well-known technical solutions in the art, the features that distinguish the described invention from the prototype were not identified and therefore they provide the claimed technical solutions with the criterion of "significant differences". Synchronously with the measurement of time instants in the described method, the numbers of the channels through which the events are received are also recorded. By designating, respectively, the channels through which events for “1” are currently being received, and for which there are no events for “0”, and recording them in the corresponding cells of the random access memory, we obtain the necessary information about each registered event. An approximate type of recorded data is presented in the table.

 The recorded data is transmitted to a computer for further mathematical processing. During the transmission of data, the status of the counters and cells of the random access memory must be unchanged, and the measurement process must be continued.

 This is realized by the presence in "Quantochron" of the second, identical to the first, part of the device in which the measurement process continues, while from the first already accumulated data is transmitted to the computer. These parts are called the rulers "1" and "2", respectively.

 The described method makes it possible to study the statistical characteristics of the streams of events arriving on many channels with high time resolution and accuracy over long time intervals due to the formation of a nonius scale of time stamps and the parallel arrival of pulse-tags to the counting inputs of several nonius counters.

 The invention is illustrated in the block diagram.

 The block diagram contains an OR 1 circuit, a clock generator 2, a clock counter 3, a switch 4 bars, a shaper 5 of service requests for a computer, a vernier generator 6, a shaper 7 of signals "Reset", a counter 8 of events, a decoder 9 of the event number, a shaper of 10 signals "Start-stop", vernier counters 11,12,13 - 1,2,3, respectively, shaper 14 signals "Record", memory cells 15,16,17 - respectively 1,2,3.

 The table shows an exemplary view of the recorded data in the described manner.

 The method is as follows. After switching on, a command counter 3 is reset from the computer, which then counts the first clock pulse received from the output of clock generator 2. The same pulse, received at the input of the switch 4 bars, sets the first ruler into measurement mode and the second into data transfer mode COMPUTER. In the first line, the counter of 8 events and all vernier counters 11,12,13 are reset to zero. The “Start-stop” signal generator 10 issues a “Start” signal to the control inputs of all the vernier counters of the first line, and they simultaneously start counting the pulses coming from the output of the vernier generator 6. The event counter receives a resolution signal due to events arriving at its input from circuit output OR 1. As soon as an event presence signal is received at any of the N inputs of the OR circuit, it will appear on its output and will be counted by a counter of 8 events. At the output of the event counter, code "1" is set. This code, through the decoder 9 and the start-stop signal generator 10, causes the Stop signal to be generated for the first nonius counter, and the Record signal generator gives a signal to record the input code combination into the first cell of random access memory (RAM) in the form of zeros and units (table). When a signal about the second event arrives, it, similarly to the first, is counted by the event counter, at the output of which the code "2" is set. As a result, the second nonius counter is stopped and the input code combination is written to the second RAM cell. All subsequent events of 3,4,5, etc., lead to a stop of the corresponding vernier counters and recording of input codes in the corresponding RAM cells.

 As a result, in the time interval between two adjacent clock marks, the recording times of events and the channel numbers along which these events occurred are recorded. The second pulse of the clock time stamp, similarly to the first, is counted by the clock counter and switches the first ruler to the data transfer mode to the computer, and the second to the measurement mode. Thus, the computer records data on the content of the clock, vernier counters, event counter and RAM cells of the first line, while the second line takes measurements, etc. The described method and device make it possible to study the statistical characteristics of the sources of events received by many channels with high time resolution and accuracy over long time intervals.

Claims (2)

 1. The method of multichannel measurement of moments of time of registration of events, which consists in fixing and storing the numbers of channels on which the events arrived, and at the same time measuring the moments of time of registration using a binary clock, characterized in that, in order to obtain high time resolution over a long interval , the formation of the clock and nonius timestamps, calculated respectively by the clock and the group of nonius counters, which are simultaneously reset and run for I count vernier time stamp on the label clock, stopping turn as events are received.  2. A device for multichannel measurement of moments of time for recording events, containing a storage device, a binary clock and a control unit for a device and transmitting data to a computer, characterized in that the binary clock consists of a clock generator and a clock counter of a vernier generator connected to it with two identical groups of vernier counters with control circuits for these counters, including the “Reset” and “Start-stop” signal conditioners, as well as two identical event counters and two memory devices, forming respectively the first and second line with a common commutator and OR circuit.

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