CA1252653A - Speech aid for laryngectomy patients - Google Patents
Speech aid for laryngectomy patientsInfo
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- CA1252653A CA1252653A CA000515902A CA515902A CA1252653A CA 1252653 A CA1252653 A CA 1252653A CA 000515902 A CA000515902 A CA 000515902A CA 515902 A CA515902 A CA 515902A CA 1252653 A CA1252653 A CA 1252653A
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- frequency
- pulse generator
- power source
- basic frequency
- basic
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Abstract
SPEECH AID FOR LARYNGECTOMY PATIENTS
ABSTRACT
A speech aid for laryngectomy patients is described and comprises an electromechanical transformer with a power output stage connected upstream, a pulse generator for the production of a basic frequency, manually operated switches and electrical filters designed to vary the pulse frequency as a function of time. The power output stage in this respect comprises an electronic switch which is controlled by the basic frequency and a controlling pulse generator which switches the electronic switch off at least with temporal priority over the basic frequency.
ABSTRACT
A speech aid for laryngectomy patients is described and comprises an electromechanical transformer with a power output stage connected upstream, a pulse generator for the production of a basic frequency, manually operated switches and electrical filters designed to vary the pulse frequency as a function of time. The power output stage in this respect comprises an electronic switch which is controlled by the basic frequency and a controlling pulse generator which switches the electronic switch off at least with temporal priority over the basic frequency.
Description
,1 h~
The invention relates to a speech aid for laryngectomy patients.
Electrical speech aids of this type produce a mechanical vibration which is applied externally and passes through the soft tissues of the neck into the area of the mouth and throat and may be modulated by means of tongue and throat movements into comprehensible speech. Speech aids of this type in most cases have the shape of torches, are held in the hand and have their front portions, which contain the electromechanical transformer, pressed against the neck. Rechargeable batteries are in most cases used as a source of power.
An essential drawback of the appliances known up to now lies in that either very large batteries have to be used making long-term use of the device tiring, or the batteries must be frequently recharged and therefore that a soare device must be available.
In addition, if speech which is suitably articulated and comprehensible is to be produced fluctuations in the loudness and intonation of normal voice production must be matched. Thbse floctuations vary from voice to voice.
In order to produce speech which sounds completely natural a large number of tone parameters must be varied and this has to be carried out manually by the user. This makes learning how to handle the appliance more difficult and also increases its size and heaviness as a result of the multiplicity of components which are required.
Starting from the above-mentioned prior art, the object of the present invention is to provide a speech aid whose cost and size are as low as possible and which is light as a result of low power consumption whils~
ensuring high-quality voice production.
This object is solved in that in an appliance according to the preamble of claim 1 the power output stage is provided with an electronic switch which is controllPd by the basic frequency, and in that the adjustment means ;5~
comprise a pulse generator controlling the electronic switch, which generator switches off the electronic switch at least temporally with priority over the basic frequency. This embodirnent of a power output stage ensures that all the power which flows frorn the battery into the power output stage is supplied to the electromechanical transforrner and therefore that no energy is converted into heat. The fact that the electronic switch is switched off with temporal priority over the basic frequency ensures that the basic frequency, i.e. the actual voice sound, i5 not disturbed.
In a preferred embodiment the controlling pulse generator has a basic frequency which is above the upper limit frequency of the electro-mechanical transforrner and oroduc0s a rectangular signal, the pulse generator being connected to an aojustment member in such a way that its pulse ratio is determined by the adjustment member. In this preferred embodirnent, the basic frequency is therefore interrupted by a high frequency signal so that - following low-pass filtering by the transformer -the power but not the frequency of the signal is modified.
In a further preferred embodiment the controlling pulse generator is formed as a univibrator, i.e as 8 timing member, which is triggered by the basic frequency and is connected to an adjustment member in such a way that its time constant is determined by the adjustment member. In this way a specific coherent time area i5 faded out by each oscillation of the basic frequency as a result o~ which the basic ~requency is maintained and the power of the signal may be modified.
In order to make the speech sound less monotonous, it is possible to increase loudness at the beginning of speech and let it fade away towards the end of a sentence. Skilled users carry this out by pressing and removing the appliance. In order to enable unskilled users to achiPve this natural manner of speaking and also to make it easier for skilled users, in a preferred embodiment of the invention the controlling pulse generator is provided with a first auxiliary filter which is coupled to the on/off switch such that on switching on the closing period of the electronic switch rises to the maximum value set by the adjustment member with a predetermined ;5.3 tirne constant nnd decreases with a predetelrnirled time constant on switching off. The time constants are preferably approxirnately 50 ms.
In a further preferred embodiment of the invention, the intonation, as well as the loudness, is controlled during switching on and off. This is achieved by providing the pulse generator for the production of the basic frequency with a further filter which is coupled to the on/off switch such that on switching on the basic frequency increases from a relatively low value to a set pulse generator Yalue with a predetermined time constant and decreases with a predetermined time constant on switching off. The time constants are preferably 50 ms in this case as well.
In order to be able to use the appliance for all voices, the electronicfilters which are conventionally provided and are designed to vary the pulse frequency as a function of time must be permanently adjusted to specific values. This is achieved in accordance with the invention in that the electronic filters designed to vary the pulse frequency as a function of time comprise removable connections for programming to predetermined values. This ensures high-quality voice production which is adapted to the particular manner of speaking with a minimal expenditure on components -so that the weight of the appliance is kept low.
Yoice production may be particularly "clean" if - as in the case of a further preferred- embodiment o~ the invention - the electronic filters comprise a single digital filter with a control logic and an adjustable pulse generator. In this respect the pulse generator for the production of the basic frequency is formed as a digitally controlled oscillator. The digital fi!tPr preferably operates ,according to the z-transformation principle. As a result of this digital construction programming is partîcularly simple and voice production is not dependent on the battery voltage which drops over time, since the operating frequencies of the appliance are essentially independent of voltage. In addition this embodiment ensures a particularly low power consumption as digital components may nowadays be constructed using MO~ techniques. The whole appliance may therefore be embodied as an integrated circuit with the result that the weight of the appliance may be cDnsiderably reduced.
l;~S'~t;S3 Further preferred embodiments of the invention are described in detail below with reference to the drawings, in which:
Flg. 1 shows the basic construction of an output stage of the invention;
Fig. 2 shows a first embodiment of the output stage of Fig. l;
Fig. 3 shows a further embodiment of the output stage of Fig. l;
Fig. 4 shows an output stage of Fig. 2 with loudness control during switching on and off;
Fig. 5 shows a basic circuit for tone production with analog cornponents and - -Fig. 6 shows a block diagram of the digital embodiment of the invention.
As shown in Fig. 1, the basic frequency comprises a substantiàlly rectangular signal which increases from 0 V to a voltage corresponding substantially to the battery voltage and falls away again after a predetermined period. This signal is supplied to the input of the electronic switch 10 which is controlled by a pulse generator 20. In ordsr to make control possible in such a way that the pulse generator 2û can only switch the electronic switch off and not on, the signal is supplied to the pulse generator 20 with the basic frequency, which generator then switches the appliance off giving priority to the basic signal.
The signal is supplied fror,n the electronic switch lû to a terminal of the electromechanical transformer which is preferably embodied as a magnetic system. The other terminal of the transformer 1 is connected to the current source. A protective diode is connected across the terminals.
A preferred embodiment of the arrangement of Fig. 2 will now be described in detail.
s~
In this circuit the signal is supplied with the basic frequency to a first input of a NAND-gate. The output of the NAND-gate 23' is connected in parallel to two inp~lts of a further NAND-gate 23". The output of the NAND-gate 23" is supplied on one hand to the gate connectisn of a field ef ~ect transistor 10 (VMOSFET) and, on the other hand, via a capaci tor Cf to the second input of the first NAND-gate 23'. The cathodes and anodes of two diodes Dl and D2 are located on this second input of the first NAND-~ate 23'; the anodes and cathodes are respectively connected to an end of a potentiometer 22 via resistances Rl and R2. The centre tapping of the potentiometer lies on the output of the first NAND-gate 2~
In addition, the electronic switch 10 has one terminal connected to earth and the other terminal connected to the first terminal of the electro-mechanical transformer 1. The electromechanical transformer 1 has its second terminal connected to the positive supply potential. The transformer 1 is also bridged by a diode in a known manner.
The mode of operation of the circuit of Fig. 2 will now be described indetail. As soon as the input signal at the first input of the first NAND-gate 23' increases to 8 positive level, the output of this NAND-gate falls to 0 V, provided that the second input of the NAND-gate 23' is at "1".
Since the output of the first NAND-gate 23' decreases to "D", the output of the second NAND-gate 23" increases to "1" as a result of which the transistor 10 is driven. As a result of the increase in the output of the second NAND-gate 23" the first pole of the capacitor Cf is raised to a high potential so that a current flows through the potentiometer 22, the resistor Rl and the diode Dl. The capacitor Cf is therefore discharged.
As soon as the latter has, been charged to the threshold value of the first NAND-gate 23', the output of this gate increases to "1", the second NAND-gate 23" is closed (the transistor 10 is cut off) and the first pole of the capacitor Cf drops to a low potential. The capacitor is thereby charged via the potentiometer 22, the resistor R2 and the diode D2 until its potential again exceeds the threshold value of the first NAND-gate 2~' whose output again drops to "0". The process is then repeated. It is evident from the above that the period of time during which the transistor 10 is driven is determined by the potentiometer 22, the resistor Rl and ~SZ~
the diode Dl and that the switching off tirne of the transistor 10 is determined by the other portion of the potentiometer 22, the resistor R2 and the diode D2. By adjustment of the potentiometer 22 it is not therefore the frequency which is determined but the pulse ratio of this pulse generator.
When the first input of the first NAND-gate 23' is at "0", its output is at "1" irrespective of the potential at its second input and consequently the output of the second NAND-gate 23" is E3t "0" so that the transistor remains cut off. This ensures the above-mentioned "priority control".,, A further preferred embodiment of the invention will now be described with reference to Fig. 3. This Figure shows a pulse generator 20 comprising two NAND-gates ~4'9 24", an OR-gate 24" ', a capacitor Cf and an adjustable resistor 22'. This component which i5 known per se represents an univibrator which is triggered by a flank increasing from "0"
to "1" and remains switched for a predetermined period of time ~,vhich is determined by the adjustable resistor 22' and the capacitor Cf. In this respect it i5 also ensured with this circuit that the output "11' may only be present at the OR-gate 24" ' if there is a "1" at the input of the first NAND-gate 24'., It is obviously possible to use conventional univibrators in integrated circuits instead of this circuit which is known per se. The output of the OR-gate 24" ' is connected to the gate input of the field effect transistor 10 (not shown in this case).
A preferred embodiment of the circuit of Fig. 2 will now be described with reference to Fig. 4 in which the loudness of the voice reproduction, i.e. the power supplied tp the transformer 1, increases on switching on with a predetermined time constant and falls away again on switching off with a predetermined time constant. In this embodiment of the invention one pole of an on/off switch S is connected to the positive supply voltage and its other pole i~ connected to the first terminal of a capaci tor C. The other terminal of the capacitor C is connected to an earthed resistor R
and to one pole of a light-emitting diode whose other pole is earthed. The light-emitting diode is optically coupled to the gate of a field effect transistor T both of whose other terminals bridge the resistor Rl. ~he field effect transistor T operates in this case as a controllable resistor whose resistance value is dependent on the liyht current emerging from the light-emitting diode.
The mode of operatinn of the circuit is as follows:
When the user presses the on/ofF switch S, the capacitor C is connectedto the supply voltage. It is charged via the resistor R1 and the light-emitting diode by means of the time constant determined by its capacitance and the current which is flowing. During th;s charging period, the photoelectric current emitted by the light-emitting diode drops and slowly cuts the field effect transistor off again so that its resistance value increases. Since the field effect transistor T is connected in parallel with the resistor R1 which jointly determines the drive time of the transistor ~0, the loudness set by the potentiometer 22 increases gradually after switching on to its predetermined value.
On switching off the loudness gradually decreases. Care must be taken to ensure that the field effect transistor has, when the light-emitting diode is not emitting any light current, a resistance value which is high enough to ensure that the duration of connection of the transistor 10 is only determined by R1.
Control may be carried out by a generator using analog or digital techniques.
The circuit of the speech aid upstream of the output stage will now be described with reference to, Fig. 5.
As this drawing shows, the circuit comprises a voltage-controlled oscillator 12 (VCO) whose output represents the signal with the basic fre{luency. The control input of the VCO 12 is connected to four summing resistors R
whose other ends are connected to the outputs of four components E, D, I
and M. The output frequency of the VCO 12 is therefore produced as a function of the sum Df the output voltages of the above components. The components E, D, I and M ~re described in detail below.
~s~
The cnmponent E comprises a resistance network Rf~ with several resistors connected in series whose points of connection are located on respective sockets RF1 - RFn. The network is connected at one end to the supply voltage and at its other end to a ballast resistor and simultaneously to one of the summing resistors R. The output voltage of the cornponent E is modified according to the way in which the individual resistors in the network RF are connected across the terminals RF1 - RFn via short-circuiting bridges. This output voltage determines the "end frequency" as will be described in detail below.
The component D compri~es two similar resistance networks RS with connections RSi - ~Sn and RD with connections RD1 - RDn. The first resistance network RS is connected at one end to the supply voltage and at its other end via a ballast resistor to the first pole of a switch 51. The first pole of the resistance network RD is connected to earth and its other pole to the second contact of the switch S1. The summing pole of the switch S1 is connected to an earthed capacitor CD and to a summing resistance R.
The component D operates as follows:
If the switch 51 is in the position shown in Fig. 5, the capacitor CD is charged via the resistance network RS to the voltage value determined by the ballast resistor at the output o~ the resistance network RS, which value is then added to the input of the VCO 12. If the switch is moved into its second position (not shown) the capacitor CD is completely discharged Yia the network RD.
As the outputs of the components E and D are added, the total voltage from the components E and D never falls below the value determined by the component E.
Tne component I will now be described. The component I comprises a resistance network RI with connections Rl1 - Rln (as described above) and has one end connected to the positive supply voltage and the other end connected to a series connection of two resistors which is again earthed so iS~;~
that a series connection of three resistance cornpenents is produced. The central resistance cornponent has both terminals connected to two terrninals of a switch S2 whose summ;ng terminal is connected via a resistor RIS and an earthed capacitor CIS to a summing resistor.
The component operates as follows: if the switch 52 is in the position shown in Fig. 5, the output voltage of the component I is determined by the voltage drop at the resistance network Rl. If the switch 52 is moved into its second position, the voltage drops with the time constant determined by the res;stor RIS and the capacitor CS to a relativel-y low voltage which is determined by the voltage drop via the resistance network Rl and the resistor connected downstream.
The mode of operation of the component M will now be described. If the switch S is in the position shown in Fig. 5, the battery is uncoupled and the supply voltage V+ is 0. If the switch S is moved into its second position, the charging capacitor CL is rapidly charged (as a result of the low battery impedance), while a capacitor CT connected to earth is only gradually charged via a resistor RT. The voltage at the capacitor CT is supplied to a summing resistor R.
The overall mode of operation of the circuit is as follows: the switch S ls mechanically connected to the switch 51 in such a way that in the rest condition they are in the position shown in Fig. 5. If the user presses the switch 5~51 the VCO control voltage increases from a value determined by the total output voltage of the components E, D and I to the total sum value. A short time constant is selected in this respect for ths component M, preferably 5û ms~ After this rapid increase in the input voltage for the VCO 12 the latter then falls again slowly, as a function of the time constants from the capacitor CD and the resistance network RD, to an end value which is substantially the sum of the output voltages from the components E, I and M. This slow decrease in the total voltage causes a slow drop in the output frequency of the VCO 12 so that the normal fall in the level of the voice during a sentence heard in natural speech is ensured.
If the switch 52 of the component I is pressed down frurn its rest position to the position shown in Fig. 5, it causes a rise in the "voice frequency"
and if it is released it causes a drop in the voice frequency, the rise and fall times being determined by the timing member !~ls, Cls (the "raised"
position is therefore shown in Fig. 5). This "intonation jump" leads to comparatively natural speech reproduction.
Since the resistance networks RF, RS, RD and Rl are respectively provided with tapping points which may be short-circuited via simple bridges it is possible to programme the normal rise and fall during speaking as well as beginning and end positions and an intonation jump in the way required by the language of the user. As these values differ greatly from language to language, it is possible by means of the embodiment of the speech aid of the invention to ensure optimum "programmability" with- very little expenditure on components.
A further preferred embodiment of the invention, embodied using digitaltechniques, will now be described with reference to Fig. 6. The circuit of Fig. 6 comprises a digital oscillator 4û which substantially comprises an oscillator which may be regulated via the connections RPl and RP2, which oscillator pulses a synchronous countsr. The parallel outputs of the synchronous counter are supplied to a comparator which receives its reference values via a latch. When the values from the synchronous counter and the latch are in agreement, an output signal is supplied to the output AU. An output stage as shown in Figs. 1 to 4 can be coupled to the output AU.
The latch receives its input values from a digital filter 60 which carries out a z-transformation. The coefficients of the z-transformation are in this respect determined by a control logic 64 which comprises programming connections DEC, Ml and M2. The pulse s~ate of the filter 60 is determined by a second oscillator which comprises programming connections RTl and RT2.
The mode of operation of this circuit is as follows: the b8sic frequency is determined in the pulse generator 40 by the first oscillator. The bssic ;5~
frequency is modified as a function of the values which are supplied from the digital filter 60 via the latch to the comparator. Since the pulse frequency of the digital filter 60 is determined via the programming inputs RTl and RT2 of the oscillator 62 and the coef ficients of the z-transformation are set via the control logic 64 by means of the values at the control inputs DEC, Ml and M2, any frequency behaviour may be programmed in advance. The on/off and intonation switches described in further detail above are obviously used in this respect and are coupled in the manner known to persons skilled in the art. The adjustment of the appliance to the language of the user therefore takes place via the programming inputs RPl, RP2; RTl, RT2 and Ml~ M2, D~C.
As mentioned above, use may be advantageously made of the output stage (to be coupled to the output AU) described with reference to Figs. 1 to 4, although a conventional output stage could of course also be used.
KEY TO FlGURE 6 Synchro Zahler Synchronous counter Kompar ator Comparator Latch Latch (Accum) (8attery) Kontr. Logik Control logic Koeff. Coef ficien t
The invention relates to a speech aid for laryngectomy patients.
Electrical speech aids of this type produce a mechanical vibration which is applied externally and passes through the soft tissues of the neck into the area of the mouth and throat and may be modulated by means of tongue and throat movements into comprehensible speech. Speech aids of this type in most cases have the shape of torches, are held in the hand and have their front portions, which contain the electromechanical transformer, pressed against the neck. Rechargeable batteries are in most cases used as a source of power.
An essential drawback of the appliances known up to now lies in that either very large batteries have to be used making long-term use of the device tiring, or the batteries must be frequently recharged and therefore that a soare device must be available.
In addition, if speech which is suitably articulated and comprehensible is to be produced fluctuations in the loudness and intonation of normal voice production must be matched. Thbse floctuations vary from voice to voice.
In order to produce speech which sounds completely natural a large number of tone parameters must be varied and this has to be carried out manually by the user. This makes learning how to handle the appliance more difficult and also increases its size and heaviness as a result of the multiplicity of components which are required.
Starting from the above-mentioned prior art, the object of the present invention is to provide a speech aid whose cost and size are as low as possible and which is light as a result of low power consumption whils~
ensuring high-quality voice production.
This object is solved in that in an appliance according to the preamble of claim 1 the power output stage is provided with an electronic switch which is controllPd by the basic frequency, and in that the adjustment means ;5~
comprise a pulse generator controlling the electronic switch, which generator switches off the electronic switch at least temporally with priority over the basic frequency. This embodirnent of a power output stage ensures that all the power which flows frorn the battery into the power output stage is supplied to the electromechanical transforrner and therefore that no energy is converted into heat. The fact that the electronic switch is switched off with temporal priority over the basic frequency ensures that the basic frequency, i.e. the actual voice sound, i5 not disturbed.
In a preferred embodiment the controlling pulse generator has a basic frequency which is above the upper limit frequency of the electro-mechanical transforrner and oroduc0s a rectangular signal, the pulse generator being connected to an aojustment member in such a way that its pulse ratio is determined by the adjustment member. In this preferred embodirnent, the basic frequency is therefore interrupted by a high frequency signal so that - following low-pass filtering by the transformer -the power but not the frequency of the signal is modified.
In a further preferred embodiment the controlling pulse generator is formed as a univibrator, i.e as 8 timing member, which is triggered by the basic frequency and is connected to an adjustment member in such a way that its time constant is determined by the adjustment member. In this way a specific coherent time area i5 faded out by each oscillation of the basic frequency as a result o~ which the basic ~requency is maintained and the power of the signal may be modified.
In order to make the speech sound less monotonous, it is possible to increase loudness at the beginning of speech and let it fade away towards the end of a sentence. Skilled users carry this out by pressing and removing the appliance. In order to enable unskilled users to achiPve this natural manner of speaking and also to make it easier for skilled users, in a preferred embodiment of the invention the controlling pulse generator is provided with a first auxiliary filter which is coupled to the on/off switch such that on switching on the closing period of the electronic switch rises to the maximum value set by the adjustment member with a predetermined ;5.3 tirne constant nnd decreases with a predetelrnirled time constant on switching off. The time constants are preferably approxirnately 50 ms.
In a further preferred embodiment of the invention, the intonation, as well as the loudness, is controlled during switching on and off. This is achieved by providing the pulse generator for the production of the basic frequency with a further filter which is coupled to the on/off switch such that on switching on the basic frequency increases from a relatively low value to a set pulse generator Yalue with a predetermined time constant and decreases with a predetermined time constant on switching off. The time constants are preferably 50 ms in this case as well.
In order to be able to use the appliance for all voices, the electronicfilters which are conventionally provided and are designed to vary the pulse frequency as a function of time must be permanently adjusted to specific values. This is achieved in accordance with the invention in that the electronic filters designed to vary the pulse frequency as a function of time comprise removable connections for programming to predetermined values. This ensures high-quality voice production which is adapted to the particular manner of speaking with a minimal expenditure on components -so that the weight of the appliance is kept low.
Yoice production may be particularly "clean" if - as in the case of a further preferred- embodiment o~ the invention - the electronic filters comprise a single digital filter with a control logic and an adjustable pulse generator. In this respect the pulse generator for the production of the basic frequency is formed as a digitally controlled oscillator. The digital fi!tPr preferably operates ,according to the z-transformation principle. As a result of this digital construction programming is partîcularly simple and voice production is not dependent on the battery voltage which drops over time, since the operating frequencies of the appliance are essentially independent of voltage. In addition this embodiment ensures a particularly low power consumption as digital components may nowadays be constructed using MO~ techniques. The whole appliance may therefore be embodied as an integrated circuit with the result that the weight of the appliance may be cDnsiderably reduced.
l;~S'~t;S3 Further preferred embodiments of the invention are described in detail below with reference to the drawings, in which:
Flg. 1 shows the basic construction of an output stage of the invention;
Fig. 2 shows a first embodiment of the output stage of Fig. l;
Fig. 3 shows a further embodiment of the output stage of Fig. l;
Fig. 4 shows an output stage of Fig. 2 with loudness control during switching on and off;
Fig. 5 shows a basic circuit for tone production with analog cornponents and - -Fig. 6 shows a block diagram of the digital embodiment of the invention.
As shown in Fig. 1, the basic frequency comprises a substantiàlly rectangular signal which increases from 0 V to a voltage corresponding substantially to the battery voltage and falls away again after a predetermined period. This signal is supplied to the input of the electronic switch 10 which is controlled by a pulse generator 20. In ordsr to make control possible in such a way that the pulse generator 2û can only switch the electronic switch off and not on, the signal is supplied to the pulse generator 20 with the basic frequency, which generator then switches the appliance off giving priority to the basic signal.
The signal is supplied fror,n the electronic switch lû to a terminal of the electromechanical transformer which is preferably embodied as a magnetic system. The other terminal of the transformer 1 is connected to the current source. A protective diode is connected across the terminals.
A preferred embodiment of the arrangement of Fig. 2 will now be described in detail.
s~
In this circuit the signal is supplied with the basic frequency to a first input of a NAND-gate. The output of the NAND-gate 23' is connected in parallel to two inp~lts of a further NAND-gate 23". The output of the NAND-gate 23" is supplied on one hand to the gate connectisn of a field ef ~ect transistor 10 (VMOSFET) and, on the other hand, via a capaci tor Cf to the second input of the first NAND-gate 23'. The cathodes and anodes of two diodes Dl and D2 are located on this second input of the first NAND-~ate 23'; the anodes and cathodes are respectively connected to an end of a potentiometer 22 via resistances Rl and R2. The centre tapping of the potentiometer lies on the output of the first NAND-gate 2~
In addition, the electronic switch 10 has one terminal connected to earth and the other terminal connected to the first terminal of the electro-mechanical transformer 1. The electromechanical transformer 1 has its second terminal connected to the positive supply potential. The transformer 1 is also bridged by a diode in a known manner.
The mode of operation of the circuit of Fig. 2 will now be described indetail. As soon as the input signal at the first input of the first NAND-gate 23' increases to 8 positive level, the output of this NAND-gate falls to 0 V, provided that the second input of the NAND-gate 23' is at "1".
Since the output of the first NAND-gate 23' decreases to "D", the output of the second NAND-gate 23" increases to "1" as a result of which the transistor 10 is driven. As a result of the increase in the output of the second NAND-gate 23" the first pole of the capacitor Cf is raised to a high potential so that a current flows through the potentiometer 22, the resistor Rl and the diode Dl. The capacitor Cf is therefore discharged.
As soon as the latter has, been charged to the threshold value of the first NAND-gate 23', the output of this gate increases to "1", the second NAND-gate 23" is closed (the transistor 10 is cut off) and the first pole of the capacitor Cf drops to a low potential. The capacitor is thereby charged via the potentiometer 22, the resistor R2 and the diode D2 until its potential again exceeds the threshold value of the first NAND-gate 2~' whose output again drops to "0". The process is then repeated. It is evident from the above that the period of time during which the transistor 10 is driven is determined by the potentiometer 22, the resistor Rl and ~SZ~
the diode Dl and that the switching off tirne of the transistor 10 is determined by the other portion of the potentiometer 22, the resistor R2 and the diode D2. By adjustment of the potentiometer 22 it is not therefore the frequency which is determined but the pulse ratio of this pulse generator.
When the first input of the first NAND-gate 23' is at "0", its output is at "1" irrespective of the potential at its second input and consequently the output of the second NAND-gate 23" is E3t "0" so that the transistor remains cut off. This ensures the above-mentioned "priority control".,, A further preferred embodiment of the invention will now be described with reference to Fig. 3. This Figure shows a pulse generator 20 comprising two NAND-gates ~4'9 24", an OR-gate 24" ', a capacitor Cf and an adjustable resistor 22'. This component which i5 known per se represents an univibrator which is triggered by a flank increasing from "0"
to "1" and remains switched for a predetermined period of time ~,vhich is determined by the adjustable resistor 22' and the capacitor Cf. In this respect it i5 also ensured with this circuit that the output "11' may only be present at the OR-gate 24" ' if there is a "1" at the input of the first NAND-gate 24'., It is obviously possible to use conventional univibrators in integrated circuits instead of this circuit which is known per se. The output of the OR-gate 24" ' is connected to the gate input of the field effect transistor 10 (not shown in this case).
A preferred embodiment of the circuit of Fig. 2 will now be described with reference to Fig. 4 in which the loudness of the voice reproduction, i.e. the power supplied tp the transformer 1, increases on switching on with a predetermined time constant and falls away again on switching off with a predetermined time constant. In this embodiment of the invention one pole of an on/off switch S is connected to the positive supply voltage and its other pole i~ connected to the first terminal of a capaci tor C. The other terminal of the capacitor C is connected to an earthed resistor R
and to one pole of a light-emitting diode whose other pole is earthed. The light-emitting diode is optically coupled to the gate of a field effect transistor T both of whose other terminals bridge the resistor Rl. ~he field effect transistor T operates in this case as a controllable resistor whose resistance value is dependent on the liyht current emerging from the light-emitting diode.
The mode of operatinn of the circuit is as follows:
When the user presses the on/ofF switch S, the capacitor C is connectedto the supply voltage. It is charged via the resistor R1 and the light-emitting diode by means of the time constant determined by its capacitance and the current which is flowing. During th;s charging period, the photoelectric current emitted by the light-emitting diode drops and slowly cuts the field effect transistor off again so that its resistance value increases. Since the field effect transistor T is connected in parallel with the resistor R1 which jointly determines the drive time of the transistor ~0, the loudness set by the potentiometer 22 increases gradually after switching on to its predetermined value.
On switching off the loudness gradually decreases. Care must be taken to ensure that the field effect transistor has, when the light-emitting diode is not emitting any light current, a resistance value which is high enough to ensure that the duration of connection of the transistor 10 is only determined by R1.
Control may be carried out by a generator using analog or digital techniques.
The circuit of the speech aid upstream of the output stage will now be described with reference to, Fig. 5.
As this drawing shows, the circuit comprises a voltage-controlled oscillator 12 (VCO) whose output represents the signal with the basic fre{luency. The control input of the VCO 12 is connected to four summing resistors R
whose other ends are connected to the outputs of four components E, D, I
and M. The output frequency of the VCO 12 is therefore produced as a function of the sum Df the output voltages of the above components. The components E, D, I and M ~re described in detail below.
~s~
The cnmponent E comprises a resistance network Rf~ with several resistors connected in series whose points of connection are located on respective sockets RF1 - RFn. The network is connected at one end to the supply voltage and at its other end to a ballast resistor and simultaneously to one of the summing resistors R. The output voltage of the cornponent E is modified according to the way in which the individual resistors in the network RF are connected across the terminals RF1 - RFn via short-circuiting bridges. This output voltage determines the "end frequency" as will be described in detail below.
The component D compri~es two similar resistance networks RS with connections RSi - ~Sn and RD with connections RD1 - RDn. The first resistance network RS is connected at one end to the supply voltage and at its other end via a ballast resistor to the first pole of a switch 51. The first pole of the resistance network RD is connected to earth and its other pole to the second contact of the switch S1. The summing pole of the switch S1 is connected to an earthed capacitor CD and to a summing resistance R.
The component D operates as follows:
If the switch 51 is in the position shown in Fig. 5, the capacitor CD is charged via the resistance network RS to the voltage value determined by the ballast resistor at the output o~ the resistance network RS, which value is then added to the input of the VCO 12. If the switch is moved into its second position (not shown) the capacitor CD is completely discharged Yia the network RD.
As the outputs of the components E and D are added, the total voltage from the components E and D never falls below the value determined by the component E.
Tne component I will now be described. The component I comprises a resistance network RI with connections Rl1 - Rln (as described above) and has one end connected to the positive supply voltage and the other end connected to a series connection of two resistors which is again earthed so iS~;~
that a series connection of three resistance cornpenents is produced. The central resistance cornponent has both terminals connected to two terrninals of a switch S2 whose summ;ng terminal is connected via a resistor RIS and an earthed capacitor CIS to a summing resistor.
The component operates as follows: if the switch 52 is in the position shown in Fig. 5, the output voltage of the component I is determined by the voltage drop at the resistance network Rl. If the switch 52 is moved into its second position, the voltage drops with the time constant determined by the res;stor RIS and the capacitor CS to a relativel-y low voltage which is determined by the voltage drop via the resistance network Rl and the resistor connected downstream.
The mode of operation of the component M will now be described. If the switch S is in the position shown in Fig. 5, the battery is uncoupled and the supply voltage V+ is 0. If the switch S is moved into its second position, the charging capacitor CL is rapidly charged (as a result of the low battery impedance), while a capacitor CT connected to earth is only gradually charged via a resistor RT. The voltage at the capacitor CT is supplied to a summing resistor R.
The overall mode of operation of the circuit is as follows: the switch S ls mechanically connected to the switch 51 in such a way that in the rest condition they are in the position shown in Fig. 5. If the user presses the switch 5~51 the VCO control voltage increases from a value determined by the total output voltage of the components E, D and I to the total sum value. A short time constant is selected in this respect for ths component M, preferably 5û ms~ After this rapid increase in the input voltage for the VCO 12 the latter then falls again slowly, as a function of the time constants from the capacitor CD and the resistance network RD, to an end value which is substantially the sum of the output voltages from the components E, I and M. This slow decrease in the total voltage causes a slow drop in the output frequency of the VCO 12 so that the normal fall in the level of the voice during a sentence heard in natural speech is ensured.
If the switch 52 of the component I is pressed down frurn its rest position to the position shown in Fig. 5, it causes a rise in the "voice frequency"
and if it is released it causes a drop in the voice frequency, the rise and fall times being determined by the timing member !~ls, Cls (the "raised"
position is therefore shown in Fig. 5). This "intonation jump" leads to comparatively natural speech reproduction.
Since the resistance networks RF, RS, RD and Rl are respectively provided with tapping points which may be short-circuited via simple bridges it is possible to programme the normal rise and fall during speaking as well as beginning and end positions and an intonation jump in the way required by the language of the user. As these values differ greatly from language to language, it is possible by means of the embodiment of the speech aid of the invention to ensure optimum "programmability" with- very little expenditure on components.
A further preferred embodiment of the invention, embodied using digitaltechniques, will now be described with reference to Fig. 6. The circuit of Fig. 6 comprises a digital oscillator 4û which substantially comprises an oscillator which may be regulated via the connections RPl and RP2, which oscillator pulses a synchronous countsr. The parallel outputs of the synchronous counter are supplied to a comparator which receives its reference values via a latch. When the values from the synchronous counter and the latch are in agreement, an output signal is supplied to the output AU. An output stage as shown in Figs. 1 to 4 can be coupled to the output AU.
The latch receives its input values from a digital filter 60 which carries out a z-transformation. The coefficients of the z-transformation are in this respect determined by a control logic 64 which comprises programming connections DEC, Ml and M2. The pulse s~ate of the filter 60 is determined by a second oscillator which comprises programming connections RTl and RT2.
The mode of operation of this circuit is as follows: the b8sic frequency is determined in the pulse generator 40 by the first oscillator. The bssic ;5~
frequency is modified as a function of the values which are supplied from the digital filter 60 via the latch to the comparator. Since the pulse frequency of the digital filter 60 is determined via the programming inputs RTl and RT2 of the oscillator 62 and the coef ficients of the z-transformation are set via the control logic 64 by means of the values at the control inputs DEC, Ml and M2, any frequency behaviour may be programmed in advance. The on/off and intonation switches described in further detail above are obviously used in this respect and are coupled in the manner known to persons skilled in the art. The adjustment of the appliance to the language of the user therefore takes place via the programming inputs RPl, RP2; RTl, RT2 and Ml~ M2, D~C.
As mentioned above, use may be advantageously made of the output stage (to be coupled to the output AU) described with reference to Figs. 1 to 4, although a conventional output stage could of course also be used.
KEY TO FlGURE 6 Synchro Zahler Synchronous counter Kompar ator Comparator Latch Latch (Accum) (8attery) Kontr. Logik Control logic Koeff. Coef ficien t
Claims (10)
1. A speech aid for laryngectomy patients having an electromechanical transformer with a power output stage, with at least one adjustable pulse generator for the production of a basic frequency, with at least two switches which may be manually operated for the on and off controls of the transformer and for the variation of the pulse frequency, with electrical filters designed to vary the pulse frequency as a function of time and with adjustment means for the adjustment of the output power of the power output stage, characterized in that the power output stage comprises an electronic switch controlled by the basic frequency and the adjustment means comprises a pulse generator controlling the electronic switch, which generator cuts off the electronic switch at least temporally with priority over the basic frequency.
2. A speech aid as claimed in claim 1, character-ized in that the controlling pulse generator has a basic frequency which is above the upper limit fre-quency of the electromechanical transformer and pro-duces a rectangular signal, the pulse generator being connected to an adjustment member in such a way that its pulse ratio is determined by the adjustment member.
3. A speech aid as claimed in claim 1, character-ized in that the controlling pulse generator is formed as a univibrator which is triggered by the basic fre-quency and is connected to an adjustment member in such a way that its time constant (tR) is determined by the adjustment member.
4. A speech aid as claimed in claim 2 or 3, charac-terized in that the controlling pulse generator is provided with a first auxiliary electronic filter which is connected to the on/off switch in such a way that on switching on the closing period of the electronic switch increases with a predetermined time constant (t01) to the maximum value determined by the adjustment member and on switching off falls with a predetermined time constant (t02), both time con-stants (t01, t02) preferably being 50 ms.
5. A speech aid as claimed in claim 1, 2 or 3, characterized in that the pulse generator is provided with a second auxiliary filter for the production of the basic frequency, which filter is connected to the on/off switch in such a way that on switching on the basic frequency increases from a relatively low value to the value set for the pulse generator with a predetermined time constant (t'01) and falls, on switching off, with a predetermined time constant (t'02), both time constants preferably being 50 ms.
6. A speech aid for laryngectomy patients having an electromechanical transformer with a power output stage, with at least one adjustable pulse generator for the production of a basic frequency, and at least two switches which can be manually operated for the on and off controls of the transformer and for the variation of the pulse frequency, with electronic filters for the production of time dependencies of the variation of the pulse frequency, characterized in that the electronic filter for the production of the time dependencies of the variations of the pulse frequency have interruptable connections for program-ming to predetermined values.
7. Speech aid according to claim 6, characterized in that the electronic filter consists of a single digital filter with a control logic and an adjustable pulse generator and that the pulse generator for the production of the basic frequency is constructed as a digitally controlled oscillator, the digital filter preferably working according to the principle of z-transformation.
8. A speech aid to be used by postlaryngectomy patients comprising;
a power output stage means having an electro-mechanical transformer;
means for providing a power source having a basic frequency to the electromechanical transformer;
adjustment means having at least one adjustable pulse generator for adjusting the basic frequency of said power source to form an adjusted frequency of said power source;
a first switch means moved to an off position in response to said adjusted frequency and moved to an on position in response to said basic frequency, thereby assuring that substantially all of said power source flows from said means for providing said power source to said electromechanical transformer;
a second switch means for controlling said adjustable pulse generator to adjust said basic fre-quency to said adjusted frequency; and at least one electrical filter connected to said adjustment means and varying said adjusted pulse of said power source relative to a time constant.
a power output stage means having an electro-mechanical transformer;
means for providing a power source having a basic frequency to the electromechanical transformer;
adjustment means having at least one adjustable pulse generator for adjusting the basic frequency of said power source to form an adjusted frequency of said power source;
a first switch means moved to an off position in response to said adjusted frequency and moved to an on position in response to said basic frequency, thereby assuring that substantially all of said power source flows from said means for providing said power source to said electromechanical transformer;
a second switch means for controlling said adjustable pulse generator to adjust said basic fre-quency to said adjusted frequency; and at least one electrical filter connected to said adjustment means and varying said adjusted pulse of said power source relative to a time constant.
9. A speech aid according to claim 8 wherein said adjusted frequency of said power source has a rectan-gular shape and is higher than said basic frequency of said power source so that said adjusted frequency is higher than an upper limit frequency detectable by said electromechanical transformer; and said adjustment pulse generator determining a pulse ratio of said basic frequency to said adjusted frequency.
10. A speech aid to be used by postlaryngectomy patients comprising:
a power output stage means having an electro-mechanical transformer;
means for providing a power source having a basic frequency to the electromechanical transformer;
adjustment means having at least one adjustable pulse generator for adjusting the basic frequency of said power source to form an adjusted frequency of said power source;
a first switch means moved to an off position in response to said adjusted frequency and moved to an on position in response to said basic frequency, thereby assuring that substantially all of said power source flows from said means for providing said power source to said electromechanical transformer;
a second switch means for controlling said adjustable pulse generator to adjust said basic fre-quency to said adjusted frequency; and at least one electronic filter connected to said adjustment means and varying said adjusted pulse of said power source relative to predetermined time constants by means of an interruptable connection means.
a power output stage means having an electro-mechanical transformer;
means for providing a power source having a basic frequency to the electromechanical transformer;
adjustment means having at least one adjustable pulse generator for adjusting the basic frequency of said power source to form an adjusted frequency of said power source;
a first switch means moved to an off position in response to said adjusted frequency and moved to an on position in response to said basic frequency, thereby assuring that substantially all of said power source flows from said means for providing said power source to said electromechanical transformer;
a second switch means for controlling said adjustable pulse generator to adjust said basic fre-quency to said adjusted frequency; and at least one electronic filter connected to said adjustment means and varying said adjusted pulse of said power source relative to predetermined time constants by means of an interruptable connection means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19853529533 DE3529533A1 (en) | 1984-09-05 | 1985-08-17 | CRYSTALLINE-LIQUID TRANS-4- (TRANS-5-SUBSTITUTED-1,3-DIOXANE-2-YL) CYCLOHEXANCARBONIC ACID ESTER |
| DEP3529533 | 1985-08-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1252653A true CA1252653A (en) | 1989-04-18 |
Family
ID=6278771
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000515902A Expired CA1252653A (en) | 1985-08-17 | 1986-08-13 | Speech aid for laryngectomy patients |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1252653A (en) |
-
1986
- 1986-08-13 CA CA000515902A patent/CA1252653A/en not_active Expired
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