Modern digital technologies require high-quality frequency-time support. In practice, the use of digital signal synchronization devices (DSSD), the purpose of which is the formation of clock signals, has become widespread. Various methods of technical diagnostics are used to ensure the specified quality of clock signals, increase the reliability and resource of the DSSD. The paper is devoted to solving an urgent problem, which is to develop software and hardware to automate the process of technical diagnostics of DSSD. It also investigates the automated system of technical diagnostics which is constructed on technology of multichannel monitoring with use of the sensor of the adaptive digital phase discriminator protected by the patent for an invention. The authors carried out the practical development and experimental researches of the diagnostic system using the multichannel sensor and the P4000winXP software. The research results confirm the possibility of transmitting the results of measurements of clock signals using IP technologies and conducting automated processing of the obtained data in real time, which increases the reliability of the operator's decision and simplifies the diagnostic process.
State-of-the-art digital information and
communication systems, digital substations of
SMART Grid electrical networks, other technical
facilities using high technology, including the
country’s critical infrastructure, require
highquality time-and-frequency support. An important
role in such a support is played by the processes
of formation and transmission of clock signals,
which are based on modern digital information
processing technologies. In practice, the use of
digital signal synchronization devices (DSSD),
which are designed to generate and produce
synchronized signals that must meet the specified
technical requirements, has become widespread to
solve the problem of time-and-frequency support
[
Various methods of technical diagnostics are
used in order to ensure the desired quality of clock
signals, reliability improvement and service life of
the DSSD. Technical diagnostics, through the
timely identification of inconsistencies and their
causes, improve maintenance, reliability and
efficiency of operation of DSSDs [
The current approaches to solving the
problems of quality control and diagnostics of
DSSD at the stages of production, introduction
into service and maintenance do not meet modern
requirements for functionality. The existing
technical facilities in Ukraine do not have a
uniform system for transmitting accurate time
signals from reference standards and
consequently cannot meet the requirements of all
users of frequency-time information [
According to the results of the analysis of
technological processes of production and
technical operation (TPP TO) of DSSD, it is
established that the formation of clock signals
with the specified accuracy and reliability is
impossible without the use of automated control
of signal quality and diagnostics of the state of
devices and synchronization system as a whole
[112]. In the regulatory document on technical
information protection [
The automated control system of these technological processes in its structure provides for the use of an automated subsystem of control and testing, which according to DSTU 2226-93 is designed to “automate the testing of industrial products and control its performance for compliance with regulations.”
The generalized structural scheme of the automated control system of TPP TO of DSSD with the use of diagnostic results is shown in Fig. 1. The control process receives feedback through digital technologies. In this case, from the standpoint of information functioning, the control process can be represented as a process of forming data that is moved and processed. Therefore, the functional composition of the information part of the control system of TPP TO of DSSD can be represented by the following subsystems: measuring (data collection device), information processing (calculation, storage, decision making and formation of control actions) and transmission.
The analysis of the process of diagnosing
DSSD under the conditions of their production
and technical operation based on the system
approach determines the expediency of using
multichannel monitoring technology, which
provides multiple productivity of the diagnostic
process and increases the reliability of data
analysis results used to make decisions on TPP
TO technological process parameters [
Decision-making tools are specific components of an automated diagnostic system. Being a control unit, they are composed of a number of specialists and a body of knowledge, competence and methods they possess.
It is important that, in fact, it is on the basis of these sensors that a decision is made on the formation of the necessary control actions.
Measuring multichannel tools, sensors
inclusive, have reference oscillators. Reference
oscillators (RO) are based on the principle of
automatic frequency control of a quartz oscillator
with deviation control and adaptive digital phase
discriminator (ADPD) [
It is scientifically substantiated that
calculations and estimations of DSSD
characteristics need to be carried out on the basis
of directly measured in time domain discrete
samples of an error of time which form the basic,
first level [
In case of time error measurement at τ interval, starting from the t moment, time interval error function ТІЕt(τ) is used, which has the following mathematical definition: ТІЕt ( ) ТIt ( ) ТIОП ( ) Т(t ) Т(t) - ТОП (t ) ТОП (t) Т(t ) ТОП (t )- Т(t) ТОП (t), (1) where ТОП(t) – time function of the reference (sample) signal;
ТІt(τ) – time interval function, which is
determined from the expression:
ТІt ( ) Т(t ) Т(t) , (2)
that “is a measure of the τ time interval, which
begins at time t, for the studied signal (provided
that there is an ideal reference signal)” [
2н
The next levels of the hierarchy of the process of diagnosing DSSD should provide calculations of TIErms and MTIE, characteristics of instantaneous frequency, frequency fluctuations, DSSD operating modes.
For example, the MTIE estimate can be made
for the τ0 sampling period based on the results of
N measurements of evenly spaced discrete xi
samples, using the formula [
MTIE(n 0 ) 1mkaNxn(kmiakxnxi (3) (4) min xi ),
kikn where n 1,2,..., (N 1) .
It is possible to obtain the values of discrete
samples of time interval error ТІЕ measured in the
time domain by using an adaptive digital phase
discriminator (ADPD), which is protected by a
patent of Ukraine for an invention [
The multi-channel measuring tools of the automated diagnostics system have a certain number of sensors which make it possible to measure simultaneously the control of several clock signals. In the process of measurements, the control of the periodicity, amplitude and shape of the clock signals is performed. The results of these processes, presented in digital format, are processed by a microcontroller and transmitted in text format using IP technology.
The principles of construction of multichannel measuring tools make it possible to classify their implementation as intelligent sensors that work on rather complex algorithms and allow to provide the device with additional functionalities, such as signal filtering, adaptation, correction, failure detection, reconfiguration of the measuring circuit, etc.
The practical implementation of an automated diagnostic system with a multi-channel meter and the developed P4000winXP software provides the possibility of simultaneous visualization of the measurement results of four clock signals. In addition to dynamic graphs, the monitor screen displays service information (GO mode, availability and format of controlled clock signals, etc.), which expands the possibilities for analyzing the data used by the operator in the decision-making process.
Figure 3 shows an example of the visualization
of measurement results obtained in real time from
four sensors. Text data generated by two sensors
selected by the operator is displayed as dynamic
graphs in real time. The figure shows fragments
of the parameters of TIE controlled clock signals
(Channel C0 and Channel C1) of two DSSD,
which are in different modes in the observation
time interval from 443 s to 1153 s [
This example demonstrates the ability of the developed software and hardware to provide transmission using IP technology direct and independent measurement results of TIE controlled DSSD clock signals. Automated realtime data processing with centralized accumulation provides the presentation of measurement results in an operator-friendly format, which simplifies the diagnostic process and increases the reliability of decision-making.
Based on the results of scientific and innovative project developments and experimental research performed within the state budget, it can be stated that the created software and hardware for automated diagnostics of digital signal synchronization devices is the state-of-theart system developed in Ukraine. The automated system can be used effectively to monitor the timing of clock signals in various sectors of the country’s economy, as well as to enhance the information sovereignty, defense and security of the state.