GB2248941A - Multimeter with speech synthesizer - Google Patents

Abstract

A multimeter includes a speech synthesizer (24) to audibly communicate measured values of preselected parameters. The output signal of a measuring unit (21) is converted (23) into a digital signal and combined (31) with control signals from selection units (15, 20, 26) for the type and ranges of parameters, and language, and an address word is produced which corresponds to the address in a memory (33) where digital audio signal information corresponding to the measured and selected variables is stored. This information is retrieved (29), converted to an analog audio signal (34) and acoustically reproduced (25). <IMAGE>

Description

SPEAKING MEASURING APPARATUS The present invention relates to a measuring apparatus for values of electrical parameters, comprising an input unit, a selection unit, a measuring unit and a communication unit.

BACKGROUND OF THE INVENTION Measuring apparatuses of the type described hereabove are widely used in electric and electronic laboratories where they are commonly employed to measure AC and DC voltages or currents, resistances or inductivities of electric or electronic circuits. In response to different specific requirements of the users, there exist separate measuring devices for each of the above mentioned parameters but also combined devices which comprise a selection switch - in order to preselect the nature of parameters to be measured.

All of those measuring devices which are used manually in order to measure electrical parameters of certain points of the electric circuits of e.g. an electric appliance to be repaired or of test boards or the like have one feature in common: their input contacts must be connected by cables with the points to be measured or with a reference point, whereby in general the input terminals of the device are comprised of female plugs and one end of each cable carries a male plug. The other end of at least one cable carries a touch head which is brought into contact with the point to be measured.

Typically, the user would bring the touch heads into position and read thereafter the indication of the display unit, analog or digital, wherefore he needs to turn his attention away from the contact point of the touch head in order to look at the display unit.

During measurements on complicated electronical circuit boards, where the packing density of electronical components can be very high, it frequently happens that during the change of observation from the contact point to the display, the touch head slips away from the desired location. If it arrives at a different location, the result is a simple measurement error which will remain in most cases without serious consequences. It is, however, also possible that the slipping of the touch head causes short circuits between points of different potential, which can in certain cases destroy a chip or other components.

Further, the known devices are somehow combersome to use and require often time consuming double checking of measurements which seem incorrect. With a device such as known from the prior art, each time when a new measurment is to be carried out, the user has to install the touch heads first on the measuring point and then look on the display.

OBJECT OF THE INVENTION It is therefore an object of the present invention to create a measuring apparatus which does not give rise to the drawbacks of the known devices and in particular, which helps to avoid distructive incidents during measurements.

It is another object of the present invention to create a measuring apparatus which helps to avoid time consuming unnecessary tasks or actions of the user.

It is a particular object of the present invention to create a measuring apparatus which permits to maintain the users attention at all times during the measurement concentrated on the point of contact of the touch head or of whatever particular utensil is used.

SUMMARY OF THE INVENTION These and other objectices are obtained with a measuring device of the type as mentioned above, which is further characterized in that said communication unit comprises a speech synthesizer and an interface for adapting output signals of the measuring unit to the required format of signals for the speech synthesizer.

With such speech synthesizer it is possible to relief the user from the necessity to withdraw his attention from the contact point in order to direct it to the display device because the measured value is communicated to him in audible manner.

Even though an optical display unit may not be required anymore in an apparatus according to the present invention, advantageously said communication unit may still comprise an analog or digital optical display unit capable of displaying values of the measured parameters simultaneously or alternatively to the audible communication of said values through said speech synthesizer.

Whereas optical analog or digital displays produce information in a way which is understandable for users who speak whatever language, audible communications are in principle subject of their expression is a certain language. Advantageously therefore, a measuring apparatus according to the present invention may have a communication unit which comprises a language selection unit to preselect the language in which said synthesizer is to reproduce said measured values.

According to a particular embodiment of the present invention, the interface of the communication unit which connects the measuring unit to the speech synthesizer may comprise an analog/digital converter and an address table.

Typically, said measuring unit is connected to a parameter selection unit for the type of parameters to be measured and/or for ranges of values of said parameters, and in that said parameter selection unit is connected also to said interface unit.

For optimal applicability of a measuring apparatus according to the present invention, said speech synthesizer is connected to a loudspeaker which is incorporated in the measuring apparatus.

Alternatively or additionally it may also have output ports for ear phones, which may be useful for applications where many independent users work in the same room and where confusion may occur if several independent measurements are carried out simultaneously by different users.

According to a possible embodiment of the present invention, said speech synthesizer may include a control unit which is connected to a memory in which a plurality of speech signals corresponding to the identification of said parameters and/or to a plurality of discrete values of said electrical parameters are stored.

Thus,- the appearance of a certain analog measuring result which has been translated into digital form, may be fed into this control unit of the communication unit for producing command signals which are adapted to retrieve a particular address in the memory of the synthesizer unit in which the appropriate audio information is stored in digital form and for sending this information to a digital/analog converter and further to the loudspeaker. Where measuring devices are used which have a selection unit for different ranges of values and/or for different parameters to be measured, the interface may also be connected to said selection unit in order to combine the output signal of the measuring unit with the output signal signal of the parameter or range selection unit, before sending a command signal to the control unit which takes into the account the output signals of both, the parameter selection unit and the measuring unit and, where applicable also of the language selection unit.

As it may be desirable to have the audible communication of the measured values repeated from time to time, the apparatus according to the present invention may comprise a timing circuit for applying command signals to the synthesizer in consecutive intervals independent from the measured values.

In order to produce audible communications of the measured values only when it is desired, at least one of the touch heads which may be connected to said input unit for communicating the electrical parameters to be measured to the measuring unit, may comprise a trigger for actuating the audible communication of the measured parameter values.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will hereinafter be described in detail with reference to the drawings, whereof Fig. 1 is a perspective view of a measuring apparatus according to the present invention; and Fig. 2 is a block diagram of the apparatus of Fig.l.

DETAILED DESCRIPTION OF THE INVENTION Fig. 1 illustrates a typical multi-function, multi-range measuring apparatus as commonly used in electric and electronic laboratories, and which has been modified according to the present invention. The only visible modifications of this device are screen 11 which covers a loudspeaker incorporated in the interior of the housing 14 of the apparatus which is commonly called a multimeter, and optionally an output port for ear phones designated by reference numeral 13.

The traditional visible components of the multimeter are a positive terminal 3 and a negative terminal 4 for connection of measuring cables, a selection swich 5 for the preselection of types of parameters 6, 7, 8 and 10 as well as for a certain range of values e.g. 6, 6a, 6b within a given selected parameter, a display 2 which, in the illustrated case, is an analog display in form of an angular sector scale, and an on/off switch 12. Reference number 15 is an AC/DC switch.

Terminals 3 and 4 receive, as mentioned above, measuring cables which carry at their near ends pIugs to be engaged with said terminals and at their far ends they carry e.g. touch heads which have metallic tips which are put in contact with any point of e.g. an integrated circuit board or the like in order to measure the potential of this point with respect to a reference point with which the other touch head is in contact. It is well known, of course, to provide the second cable with a claw in order to more reliably fix it to a reference point if such is desired.

- Fig. 2 shows a block diagram of a measuring apparatus according to the present invention. Positive and negative input ports 27 and 28 lead the electrical parameter to be measured into the measuring unit 21 which has previously been set in order to adjust the measurement unit to the expected order of magnitude of the parameter to be measured. The preselection of this order of magnitude as well as of the nature of the parameter and the AC/DC selection takes place through selection unit 20.

Conventionally, the measuring unit is connected to a display unit 22 which may be embodied by scale 2 of Fig.1.

According to the invention an interface 32 is provided which comprises a converter unit 23 such as an A/D converter which converts the analog output signals of the measuring unit 21 into digital signals. As after preselection of the order of magnitude and of the nature of the parameter the output signal of the measuring unit is only a relative signal situated between minimum and maximum of the scale 2, it is necessary to take into account the information of the selected type of parameters and the range thereof in order to obtain the correct final communication of the measured value.

The A/D converter 23 translates the analog output signal of the measuring unit 21 into a digital word, which is sent to an address table 31 which receives also the output signals of the parameter selection unit 20 and the language selection unit 26. The information provided by the AC/DC switch 15 of Fig. 1 is considered to be included in the output signal of the parameter selection unit 20, since its impact on the further signal processing is analog to the one of the output signal concerning the selected parameters and ranges.

In the address table 31 the digital word of the converter 23 and the output signals of the two selection units are combined and translated into an address of a memory in which audio information signals corresponding to a plurality of linguistic words of discrete values of the measured parameters and possibly of the nature of the parameters are stored. The language selection unit 26 may e.g.

operate such as to add a control digit to the address word which control digit determines a sector of the memory 33 in which digital audio signal information according to the selected language is stored. The number of languages to select may be chosed according to the specific requirements and is only limited by the size of the memory 33. The output signal of the parameter selection unit 20 may be processed similarly to the one from the language selection unit.

Since the user generally needs to turn his attention away from the measuring point anyway to the multimeter for preselection of the nature of the parameters to be measured, it may be expected that he does not need to be audibly reminded of the selected parameter at each measurement. It is therefore possible to omit the audible communication of the identification of the nature of the selected parameter. It is clear, however, that it is also possible to include the identification of this parameter in each audible communication.

The address word is communicated to control unit 29 which retrieves the digital audio information which is stored in memory 33 under the given address. Hereafter, the digital audio information is fed to a digital/analog converter 34 where an analog audio signal is produced which is sent to the loudspeaker 25 for audible reproduction of the linguistic word corresponding to the measured value, including the identification of the measured parameter or not.

A timing circuit 30 is connected to the control unit 29 which produces tact signals for triggering repeated applications of the command signals of the control unit 29. This timing circuit serves to produce repeated audible communications of the measure values irrespective of the fact whether the touch head is maintained at the same point or moved on to another point. Thus, repetitive measurements may be carried out on the same point without the necessity of disengaging and reingaging the touch head to the point which would be required if only one audible communication would be produced when the touch head contacts a particular point.

The timing unit 30 may have a second task, which consists in a cut-off function which terminates the audible communication of the measured value after a desired, possibly pre-selectable number of repetitions of the same measurement.

The touch heads may alternatively comprise trigger buttons in order to call an audible communication of the measured value in cases where this is desired.

Another optional feature which may be provided in a measuring apparatus according to the present invention is a volume regulator for the loudness of the acoustically communicated information.

It may also be desirable to provide means for acoustically indicating if the measured value of the selected parameter is higher than or too small for the selected range of the parameter. In that case an acoustical alarm communication such as: "Please select a higher (or lower) range" may be produced. Such alarm may be implemented in the same principle way as the other audible communications described hereinabove, whereby the signal of the measuring unit 21 is first compared in a comparator with a range of desired signals and if lack of correspondence is found, the nature of a too high or too low signal is determined in response to the observation if the measured signal is higher than a maximum or lower than a minimum signal. In both cases the address which is attributed to the converted digital signal concerns an information relating to the above mentioned alarm messages.

The invention has been described herein with reference to an embodiment, it being understood that the scope of the invention extends over any modification which may appear obvious to the expert in the art.

Claims (10)

1. Measuring apparatus for values of electrical parameters, comprising an input unit, a selection unit, a measuring unit and a communication unit, characterized in that said communication unit comprises a speech synthesizer (24) and an interface (32) for adapting output signals of the measuring unit (21) to the required format of signals for the speech synthesizer (24).

2. The measuring apparatus of claim 1, characterized in that said communication unit comprises an analog or digital display unit (22) capable of displaying values of the measured parameters simultaneously or alternatively to the communication of said values through said speech synthesizer (24).

3. The measuring apparatus of claim 1 or 2, characterized in that said communication unit comprises a language selection unit (26) for the language in which said synthesizer (24) is to reproduce said measured values.

4. The measuring apparatus of claim 3, characterized -in that said interface (32) of the communication unit comprises an analog/digital converter (23) and an address table (31).

5. The measuring apparatus of any one of claim 1-4, characterized in that said measuring unit (21) is connected to a parameter selection unit (20) for the type of parameters to be measured and/or for ranges of values of said parameters, and in that said parameter selection unit (20) is connected also to said interface unit (32).

6. The measuring apparatus of any one of claim 1-5, characterized in that said speech synthesizer (24) is connected to a loudspeaker (25) which is incorporated in the measuring apparatus (1) or which may be connected to the apparatus through output ports (13).

7. The measuring apparatus of any one of claim 1-6, characterized in that said speech synthesizer (24) includes a control unit (29) which is connected to a memory (33) in which a plurality of speech signals corresponding to the identification of said parameters and/or to a plurality of discrete values of said electrical parameters are stored.

8. The measuring apparatus of any one of claims 3-7, characterized in that said control unit (29) is adapted to produce speech signals for the loudspeaker (25) in response to the output signals of the measuring unit (21) and the output signals of the parameter selection unit (20) and of the language selection unit (26).

9. The measuring apparatus of any one of claim 1-7, characterized in that said interface (32) comprises a timing circuit (30) for applying command signals to the control unit (29) in consecutive intervals independent from the measured values.

10. The measuring apparatus of any one of claim 1-7, characterized in that it comprises touch heads which are connectable to said input unit (3, 4, 27, 28) for communicating the electrical parameters to be measured to the measuring unit (21), at least one of said touch heads comprising a trigger for actuating an audible communication of the measured parameter values.