Self-testing metrologic system for an analog signal transmitting device
The present invention relates to a self-testing metrologic system for a device
transmitting an analog signal, in particular a radiofrequency signal.
The invention is located in the field of analog signal transmitters, and more
5 particularly radiofrequency signal transmitters/simulators.
Such devices are notably used for testing proper operation of adapted electronic
equipment for reacting in a predictable way to a radiofrequency signal of a given wave
form, for example in the field of aeronautics for testing pieces of equipment onboard an
aircraft.
10 For this purpose, systems are known, which allow transmission of radio frequency
signals according to a predetermined template, comprising time modulation, frequency
and power information, for example provided via a man-machine interface, and the testing
of the response of an onboard piece of electronic equipment towards the transmitted
radiofrequency signal. In the case of an unsuitable response, the onboard piece of
15 electronic equipment is considered as faulty, which may cause it to be dismantled and
replaced, having an impact on the operational availability of the aircraft.
However, an unsuitable response may also be due to a fault in the transmitted
radiofrequency signal relatively to its initial specification provided by the template.
In other technical and industrial fields, as soon as a device uses an analog signal
20 transmitter with accurate specifications in terms of a time modulation, frequency and
power template, it is useful to be able to validate the transmitted analog signal relatively to
these set template values. This is valid for radiofrequency signals, but also for signals in
the laser frequency, ultraviolet, infrared optical domains.
Such a template comprises permanent or pulse time modulation information
25 allowing definition of a pulsed transmission mode or a continuous transmission mode.
In a pulsed mode, the time modulation template defines pulse durations and
repetition periods associated with an transmission frequency. The modulation template
defines a continuous transmission mode by a permanent condition.
There exists a need for temporally fine and accurate measurements of analog
30 signals transmitted by a transmitter device.
For this purpose, the object of the invention is a self-testing metrologic system of
an analog signal transmitting device able to transmit a said analog signal in a pulsed
mode or a continuous mode according to a given template comprising time modulation,
frequency and power information characterizing said transmission mode, characterized in
35 that it comprises metrologic analysis means comprising:
2
- means for comparing the signal transmitted by said transmitting device with time
modulation and power information at the rate of the pulses defined by time modulation
information of said template, said comparison means being able, during a continuous
mode transmission, to detect a difference relatively to the information of said template as
5 soon as it appears, and
- means for temporally storing in memory anomalies in the case of a detection of a
difference by the comparison means.
Advantageously, the proposed system allows self-testing for validating proper
operation, relatively to a template comprising time modulation, power and frequency
10 information of a device transmitting analog signals. Advantageously, validation is carried
out at the very high rate of the pulses and gives the possibility of providing anomaly
information in the case of a difference relatively to the template and more generally a
piece of validation or malfunction information intended for an operator.
Thus, notably when a transmitting device is a simulator used in validating the
15 operation of a piece of electronic equipment with an intended response relatively to a
received radiofrequency signal, it is possible to highlight possible malfunction of the
radiofrequency signal transmitter, which may then be distinguished from a malfunction of
the tested piece of electronic equipment.
The self-testing system according to the invention may have one or more of the
20 features below, taken independently or as a combination:
- the system comprises means for signaling anomalies stored in memory;
- said comparison means include:
- computing means able to obtain information on anomalies from the memory
storage means, and to control said means for signaling anomalies stored in memory,
25 - at least one electronic module for analyzing the signal transmitted in a
pulsed mode, and
- an electronic module for analyzing the signal in a continuous mode;
- the system further comprises detection means able to provide information on the
transmitted power and a permanent or pulsed modulation envelope of said signal
30 transmitted by the transmission device;
- said electronic module for analyzing the signal transmitted in a continuous mode
receives as an input a piece of validation information on the transmitted power and said
module is adapted for detecting a power loss relatively to a rated power threshold
corresponding to a piece of power information specified by said template;
35 - the system further comprises a comparator able to compare said information on
transmitted power and a level depending on the transmission frequency of the signal
3
specified by said template and on said power threshold corresponding to the piece of
power information specified by said template;
- said at least one electronic module for analyzing the signal transmitted in a
pulsed mode further comprises means for detecting a pulse above a threshold
5 corresponding to the piece of power information specified by said template;
- said at least one electronic analysis module further comprises means for
detecting an anomaly when said transmitting device should not transmit a signal
according to time modulation information provided by the template;
- the system comprises means for validating a component generating a
10 transmission frequency of said transmitting device and means for inhibiting switching to a
transmission mode in a continuous mode or in a pulsed mode in the case of negative
validation;
- the system comprises man-machine interface means with which it is possible to
obtain a template comprising time modulation information, transmission power
15 information, and transmission frequency information of the analog signal to be transmitted;
and
- the system comprises means for obtaining a piece of information with which it is
possible to select a said template from among a plurality of templates stored in memory.
Other features and advantages of the invention will become apparent from the
20 description which is given thereof below, as an indication and by no means as a limitation,
with reference to the appended figures, wherein:
- Fig. 1 is an example of an application of a self-testing metrologic system
according to the invention in a platform for validating electronic equipment;
- Fig. 2 is an exemplary embodiment of a self-testing metrologic system according
25 to the invention.
The invention will be described hereafter in its particular application in the field of
validation of onboard electronic equipment.
Nevertheless, this application is by no means limiting, the invention being applied
with any device transmitting an analog signal or electromagnetic wave with a given
30 specific frequency, in order to validate the transmitted signal relatively to a given
modulation, power and frequency template.
Fig. 1 illustrates an example of a platform P, comprising a system 1 fitted out with
metrologic self-testing of a transmitting device 4 according to the invention, the platform
allowing validation of a piece of electronic equipment 2 from signals transmitted by the
35 transmitting device 4.
4
The equipment 2 is for example electronic equipment onboard an aircraft which
has a given operation in response to a radiofrequency signal of a given specification.
Thus, in a usual test operation, a radiofrequency RF signal transmitting device is
used noted as 4. The RF signal is transmitted and received by the piece of equipment 2 to
5 be validated. A means 6 for testing proper operation of the piece of equipment 2 in
response to the RF signal, according to known suitable techniques not described in detail
here, is associated with the piece of equipment 2.
The system fitted out with self-testing 1 also comprises, in addition to the
transmitting device 4, a man-machine interface (MMI) 10 allowing an operator to input
10 diverse data, notably specifications of the radiofrequency signal to be transmitted by the
transmitting device 4.
Advantageously, according to an embodiment of the invention, the MMI 10 is
connected to computing means 12, for example a microcontroller, which, in addition to
controlling the transmitting device 4 according to specifications, also allow control of the
15 means 14 for metrologic analysis of the radio frequency signal at the output of the
transmitting device 4, and for comparing this radiofrequency signal relatively to a
modulation, power and frequency template defined by set template values 16 provided at
the input of the MMI 10. As already mentioned above, the template specifies time
modulation information allowing definition of the pulsed mode and of the continuous
20 transmission mode (also called CW (Continuous Wave) mode) of the radio frequency
signal, power information and frequency information of the radiofrequency signal. For a
pulsed mode, the time modulation information gives the possibility of defining the duration
of the pulses Dl and the repetition periods PRI associated with a transmission frequency
FE. The continuous mode is indicated by a time modulation information indicating
25 modulation in the permanent condition.
The analysis and comparison means 14 are associated with means 22 for
temporal storage in memory of the results of the metrologic analysis, in particular the
presence of a difference relatively to the modulation and transmitted rated power
template.
30 Further, the system comprises means 20 4 signaling to an operator the results
stored in the temporal memory storage means 22, by cyclically reading the state of the
temporal memory storage means 22.
The system fitted out with self-testing 1 gives the possibility of validating the
operational state of the transmitting device 4 and of detecting the slightest anomaly
35 relatively to the template, and of providing information relating to the anomalies to an
operator with view to maintenance of the transmitting device 4.
5
Fig. 2 illustrates an exemplary embodiment of a self-testing metrologic system 30
of a transmitting device in the radiofrequency range which is also called a radiofrequency
illuminator.
In the example of Fig. 2, the radiofrequency illuminator consists of units illustrated
5 in dotted lines which are respectively:
- a control unit 32, able to provide information (reference clock) to a programmable
synthesizer 34, which provides a radiofrequency signal corresponding to a programmed
template provided the a man-machine interface 35;
- a radiofrequency chopper 36, which applies time modulation according to the
10 programmed time template, regardless of whether this is the pulsed mode or the
continuous mode, followed by a radiofrequency amplifier 38 and an output coupler 40.
The radiofrequency illuminator produces a radiofrequency signal transmitted via an
antenna 42 to a receiver not shown.
The set template values 45 which are present at the input of the man-machine
15 interface 35 provide time modulation information, rated transmission power information
and a transmission frequency FE.
In a pulsed mode, processing of radiofrequency signals is contemplated, having
pulses of duration Dl which may be less than 100 ns, in a range of transmission
frequencies FE from 1 GHz to 20 GHz for example.
20 According to the invention, the system 30 further comprises computing means 44
in the form of a programmable microcontroller, able to execute software packages 46,
depending on the configuration file 48.
In an embodiment, a plurality of programmed templates are stored in memory in a
configuration file 48, and the set template values 45 allows an operator to select a
25 template from among a plurality of templates stored in memory. As the templates may be
programmed, it is possible to add new templates or change parameters of the templates
stored in memory.
The microcontroller 44 is capable of sending program commands to the
programmable synthesizer 34, and time modulation information of the templates to the
30 frequency chopper 36. Further, the microcontroller 44 is able to control the means for
applying metrologic analysis of the transmitted radiofrequency signal, and means for
signaling the analysis results to an operator.
The system 30 further comprises a radiofrequency power detector 50, which is a
circuit capable of detecting the energy of the transmitted radiofrequency signal. The
35 detector 50 has an operating range which encompasses the power range to be monitored
6
by adding an attenuator at the input of the circuit. For example, a power range of more
than 10dBm is contemplated.
The detector 50 receives at the input the transmitted radiofrequency signal from
the output coupler 40 and sends at the output a signal for which the amplitude depends on
5 the transmitted power and on the representative shape of the permanent or pulse
modulation envelope of the transmitted radiofrequency signal.
The detector 50 is connected at the output to a first comparator 52 which monitors
the output range of the detector in the « standby » mode, therefore in the absence of
transmission. The comparator 52 compares the amplitude of the received signal at the
10 output of the detector 50 with a threshold specific to the detector and the result of the
comparison is directly transmitted to the microcontroller 44 which may then detect a
malfunction of the detector other than the generation of radiofrequency pulses.
The output of the detector 50 is also provided to a second comparator 54 which
monitors the output range of the detector during transmission. The comparator 54
15 compares the amplitude of the signal from the detector 50 with a level computed and
transmitted by the microcontroller, depending on the radiofrequency transmission
frequency FE and on a programmed threshold S corresponding to the rated power
indicated by the template.
The respective results of the comparators 52 and 54 are transmitted to an analysis
20 module in a pulsed mode 56, comprising an electronic module 58 for monitoring the
presence of pulsed signals above the programmed threshold S corresponding to the rated
power on the one hand and an electronic module 60 for monitoring malfunction of the
radiofrequency illuminator between two transmitted pulses.
The module 58 is able to detect the presence of pulsed signals above the
25 threshold S corresponding to the rated power. Typically, as soon as a variation relatively
to the rated power in a 0.5dB range is ascertained, a piece of anomaly information is
stored in memory.
Monitoring is carried out by comparing the output of the second comparator 54
with the time modulation or modulation template information providing the pulse duration
30 Dl and the repetition period PRI, taking into account a propagation delay between the
modulation template and the output of the comparator 54. This module 58 is able to
analyze the presence of a rising edge, representative of a pulse in a time window of less
than 180 nanoseconds for example in the case of the embodiment, which gives the
- possibility of validating the pulse chopping and therefore the pulse duration Dl. An
35 anomaly detection relatively to the modulation template of less than one microsecond is
achieved. In the case of detection of an absence of pulses or on the other hand of the
7
presence of pulse(s) with a duration greater than the expected duration Dl, a piece of
anomaly information is stored in a temporal memory 62 for about 0.5 s (seconds). The
contents of the memory 62 is read by the microcontroller 44 with a repetition frequency f
of less than 0.5s, for example f=0.25s, in order to systematically read the whole of the
5 information relating to stored anomalies.
The module 60 is able to perform a comparison between the output of the first
comparator 52 and the modulation template providing the duration of the pulses Dl and
their transmission frequency FE. Thus, it is possible to detector possible parasitic pulses
outside the modulation template. In the case of detecting an anomaly, a piece of
10 information is stored in the aforementioned temporal memory 62.
The microcontroller, subsequently to reading anomalies at the pulse level,
detected and stored in the memory 62, is able to control the display means 64, giving the
possibility of displaying for an operator information relating to the operational state of the
radiofrequency illuminator, i.e. validation of the operational state or the ascertained
15 signaling of anomalies. The microcontroller 44 is connected to the display means 64.
In this embodiment, the display means 64 are produced by a set or blinking light
display, the color of which is representative of the ascertained state: green for validation of
the operational state, orange upon « standby » and red when anomalies are detected.
The duration of the displayed light signals is compatible with visual observation, for
20 example 1s. Thus, the display intended for an operator is produced in real time and allows
the tracking of the presence of anomalies detected at the pulse level. Even one anomaly
ascertained for a single pulse is reported to the operator. The latter then has the
possibility of monitoring the operation of the radiofrequency illuminator and of action,
depending on the number and occurrence frequency of the anomalies, for example by
25 stating that the radiofrequency illuminator is faulty and launching a maintenance
operation.
Further, the system 30 comprises an electronic module 66 for analysis in the
continuous transmission mode, able to detect a one-time power loss in this transmission
mode.
30 The module 66 receives at the input a piece of information for validating the
transmitted power, from the comparator 54 and detects all the variations of the output of
the comparator 54 relatively to the programmed threshold S corresponding to the rated
power. In the case of a detected variation, a piece of anomaly information is stored in a
temporal memory 68 and kept for a period of 0.5 s. Typically, as soon as a variation below
35 the rated power in a 0.5dB range is ascertained, a piece of anomaly information is stored
in memory.
8
The contents of the memory 68 is examined by the microcontroller 44 with a
repetition frequency f of less than 0.5s in order to systematically read the whole of the
information relating to stored anomalies.
Thus, the microcontroller 44 is able to provide information on the operational state
5 of the radiofrequency illuminator both when the latter is at rest (« standby » mode) and
when the latter is transmitting either in the pulsed mode or in the continuous CW mode.
Further, the microcontroller 44 is also able to monitor the programmable
synthesizer 34, subsequently to resetting or programming a new radiofrequency signal
transmission frequency, into Jews for example via MMI 35.
10 The monitoring function of the synthesizer comprises the checking of the state of
the control 32, and the monitoring of the phase-locked loop or PLL in order to check PLL
unlocking upon taking into account the new frequency of the signal and its stability
following the change in frequency.
The circuits associated with the microcontroller further comprises means for
15 preventing switching to an active transmission mode (into a continuous CW mode or into a
pulsed mode) if the frequency of the signal is not compliant with the specification.
In an alternative embodiment, in addition to or as a replacement for the signaling
means 64, the microcontroller is able to transmit in real time information on operation and
on anomalies stored in the respective temporal memories 62 and 68, to an application
20 module or to a man-machine interface so as to facilitate a maintenance operation. For
example, through a USB link connected with a computer and a communications software
package, the microcontroller informs in real time through messages on the state of the
radiofrequency illuminator, and transmits the permanent self-testing results in the different
operating modes: initialization, standby and active transmission.

CLAIMS
1.-A seif-testing metrologic system for an analog-signal transmitting device (4)
able to transmit a said analog signal in a pulsed mode or in a continuous mode, according
to a given template comprising time modulation, power and frequency information
5 characterizing said transmission mode, characterized in that it comprises metrologic
analysis means comprising:
- means (12, 14, 44, 56, 66) for comparing the signal transmitted by said
transmitting device with time modulation and power information at the rate of the pulses
defined by the time modulation information of said template, said comparison means
10 being able, during transmission in continuous mode, to detect a difference relatively to the
information of said template as soon as it appears, and
- means (22) for temporal memory storage of anomaly information in the case of a
detection of difference by the comparison means.
2.- The self-testing metrologic system according to claim 1, characterized in that it
15 further comprises means (20, 64) for signaling anomalies stored in memory.
3.- The self-testing metrologic system according to claim 2, characterized in that
said comparison means include:
- computing means (44) able to obtain anomaly information from the memory
storage means, and to control said means (20, 64) for signaling anomalies stored in
20 memory,
- at least one electronic module (56) for analyzing the signal transmitted in a
pulsed mode, and
- an electronic module (66) for analyzing the signal transmitted in a continuous
mode.
25 4.- The self-testing system according to claim 3, characterized in that it further
comprises detection means (50) able to provide out transmission power information and a
pulsed or permanent modulation envelope of said signal transmitted by the transmitting
device.
5.- The self-testing system according to claim 4, characterized in that said
30 electronic module (66) for analyzing the signal transmitted in a continuous mode receives
as an input a piece of information for validating the transmitted power and in that said
module is adapted for detecting a power loss relatively to a rated power threshold
corresponding to a piece of power information specified by said template.
6.- The self-testing system according to one of claims 4 or 5, characterized in that
35 it further comprises a comparator (54) able to compare said information on transmitted
power with a ievel depending on the transmission frequency of the signal specified by said
10
template and on said power threshold corresponding to the power information specified by
the template.
7.- The self-testing system, according to one of claims of 4 to 6,. characterized in
that said at least one electronic module (56) for analysis of the signal transmitted in a
5 pulsed mode further comprises means (58) for detecting pulses greater than a threshold
corresponding to the power information specified by said template.
8.- The self-testing system according to one of claims 3 to 7, characterized in that
said at least one electronic analysis module .(56) further comprises means. (60) for
defecting nu anomaly when said transmitting device should not transmit any signal
10 according to the time modulation information provided by the template.
9.- The self-testing system according to one of claims 3 to 8, characterized in that
it comprises means for validating a component generating a transmission frequency of
said transmitting device and means for preventing switching to a continuous or pulsed
transmission mode in the case of negative validation.
15 10.- The self-testing system according to one of claims 3 to 9, characterized in that
it comprises man-machine interface means allowing to obtain a template comprising time
modulation information, transmission power information and transmission frequency
information of the analog signal to be transmitted.
11.- The self-testing system according to claim 10, characterized in that it
20 comprises means for obtaining a piece of information allowing to select a said template
from a plurality of templates stored in memory.