DE3049530A1 - Therapy beat frequency generator - uses frequencies and waveforms stored in digital form and produced by microprocessor - Google Patents

Abstract

The beat frequency generator is designed to produce a wide range of stable frequencies and beat frequencies with variable waveform for therapeutic purposes. This is achieved by means of a microprocessor which produces the required frequencies and waveforms, from a temporary memory where they are stored in digital form. A central processing unit (13) produces waveforms and frequencies which are stored in digital form in a temporary store (17,19). A clock oscillator (15) controls the program counter (21).

Description

Device for electrical stimulation therapy

The invention relates to a device for electrical stimulation therapy at least one circuit with a pair of electrodes, at least one amplifier, a clock oscillator, a program memory and an input unit as well as a Control unit.

Such devices for electrical stimulation therapy and in particular for Interference current therapy, i.e. therapy in which there are at least two electrical circuits each with a pair of electrodes medium-frequency voltages with frequencies in the range can be applied by a few thousand hearts, moving around a low frequency amount differ from a few to a few hundred hearts, so that it is stimulating and therefore therapeutic effective beats with the corresponding low frequency arise in the body, are known. Such devices basically work satisfactorily and show an astonishing effectiveness and treatment success.

Problems arise with known analog devices in this regard on that the difference or beat frequency, especially venn this is quite small should not be sufficiently stable because it is affected by external influences, such as temperature, supply voltage, humidity, material aging and scatter values is influenced by series components. With the advent of electronic digital technology In principle, the problem of stability was largely solved by digitization. Sufficient stability of the beat frequency can be achieved digitally. In the However, digital technology can only be achieved with very extensive technical and financial resources Effort low beat frequencies are generated. For this purpose, a high-frequency, quartz-controlled oscillator is used, the frequency of which in two different ways, i.e. divided down by two different divider ratios using digital modules will. The smaller the frequency differences of the medium-frequency oscillations should, the higher the oscillator frequency must be and the larger and more expensive the effort for dividing the frequency down and for generating it is smaller Frequency differences of the medium-frequency output oscillations.

This problem arises especially when a dense frequency spectrum to be made available for treatment, so on the one hand different beat frequencies should be provided with a small distance and on the other hand in particular a treatment of this frequency spectrum quasi-continuously, possibly periodically, should be run through, so the beat frequency for example between 5 and 20 Hz should be run through in a time of 10 to 15 seconds. The required for this high resolution, i.e. the distance between two adjacent ones to be traversed one behind the other In digital technology, beat frequencies are only possible with a great deal of effort accessible. For example, with two circuits with medium frequencies in the range of approx. 4000 Hz and a desired resolution - that is the smallest frequency spacing of the two center frequencies or the smallest "pitch" "to change the beat frequency - from 0.1 Hz with a clock frequency of 160 MHz can be worked. The use of a clock oscillator and frequency divider having such a high frequency is both technical and economical Regarding the serial production of interference current devices not justifiable.

Another problem is that with the previously described Devices is not possible, with a reasonable technical effort different Waveforms, both of the medium-frequency output signals and of the beats to reach.

In order to solve the latter problem, in known devices such proceeded that various waveforms on conventional known storage means can be saved and retrieved as required.

This storage can be analog or in completely the same way after digital technology and in particular digital memories become known, be carried out digitally, with both times basically the respectively mentioned specific problems and disadvantages remain. The storage can for example on records, tape recorders, core memories, by means of magnetic disk technology or in conventional solid-state storage devices such as highly integrated Half 1 ei terspei chern, so ROMs, so read-only memories, PROMs, so programmable Read memories or EPROMs, i.e. erasable and programmable read memories take place in the appropriate known manner and the readout based on also conventional addressing technology, for example by pressing a button in a long-known way take place. The disadvantage here is - besides the mentioned analog or digital-specific problem in particular that for the The necessary treatments require a very large amount of memory. Aucn With cheap memories, like tapes, there is a risk that the signal will not cross accessed for a long time (years) with the same, good and therapeutically necessary quality can be. In addition, undesirable fluctuations in the frequency arise due to the poor synchronization of tapes.

The invention 1 is therefore based on the object of known devices of the type mentioned in such a way that with justifiable technical Expenditure of the most varied of curve shapes, especially when using interference current therapy both the medium-frequency output signals and the generated beats Sufficient frequency stability and high resolution, i.e. a small distance between neighboring ones usable frequencies, are achievable.

According to the invention, this object is basically achieved with a device solved for stimulation current therapy of the type mentioned in that a microprocessor as central control and processing unit for generating the desired curve shapes and frequencies based on the program memory, input and control unit Information and instructions are provided that the microprocessor at least a buffer is assigned in which the waveforms and frequencies in shape of instantaneous values can be temporarily stored, and that a frequency divider and a Unit for temporal address assignment is provided, which reads out the im Intermediate storage Cached instantaneous values of the curve shape due to Ensure the information required by the microprocessor to create the curves. In a preferred embodiment, it is further provided that the unit for the temporal Address assignment of at least one counter controlled by the clock oscillator or divider having.

For special use in interference current therapy, whereby the Device with at least two separate circuits and associated amplifiers is equipped, is according to the invention according to a preferred embodiment of the device intended. that each circuit has a buffer for buffering the Instantaneous values for the waveforms of the output voltages is assigned.

According to the invention, in contrast to the prior art, neither a Divide down, especially in frequency current therapy, using different divider ratios, from a high output frequency to the desired frequency or frequencies carried out, an analog storage of the most diverse to be used Curve shapes made.

Rather, by means of the device according to the invention, due to of a few output data and programs that exist in known memories are, in which case a relatively limited storage capacity is sufficient, the desired Curve shapes and treatment processes formed and stored in a buffer in the form of instantaneous values of the curves to be output are stored and from these in a determinable Read the clock. The instantaneous values of the curves are therefore in a determinable cycle retrieved in such a way that at the exit, that is, the applied to the body to be treated Electrodes the required waveform and frequency and with 1 interference current handling 1 ung the required curve shapes, frequencies and, after linear addition of the Instantaneous values of the two resulting curves inside the body are the beat frequency and the shape of the beating curve. By means of the clock oscillator, which in advantageous Embodiment having a quartz oscillator, generated clock frequency, and the frequency divider generated control signals after given values in the divider can be determined, addresses are formed by means of the device according to the invention, from which the corresponding instantaneous values for the curve formation are taken.

The device according to the invention eliminates the problems and disadvantages overcome the known devices and in particular a large variety and Freedom of therapy in electrical stimulation therapy and, above all, in the Interference current therapy achieved with little effort.

A major advantage of the device according to the invention is that that z. B. in the case of interference current, the lower limit for the frequency of the beat can be made as small as you want. Basically, the lower limit for the Beat frequency can be freely selected. The number of instantaneous values is basically determined by different waveforms of different stimulation current therapies the required curve accuracy of the generated oscillation and also with interference current the shape of the curve and the fidelity of the desired beat curve. Advantageous one proceeds in such a way that the number of instantaneous values does not go through all at the same time these variables are determined, but rather only by those of the named Size that is striven for with the greatest accuracy, i.e. the highest number at instantaneous values or support points for the output curve.

According to the invention it is achieved in particular that on the one hand any The shape of the output curve and, moreover, also in the case of interference current therapy any beat waveform can be generated by mapping the Instantaneous values is controlled according to the desired curve shape. According to the invention can therefore use simple means for very many different instantaneous values for a period can be cached and simultaneously a multitude of different Curve shapes of both the output curves and, in the case of interference current, the Beat curves can be achieved in known devices either a extremely elaborate frequency telephones or extremely large storage capacities would have required. In the case of non-sinusoidal curves such as a triangular beat In the case of known devices, technically very complex non-mechanical devices are also required Control devices.

According to a preferred embodiment of the invention, one of the quartz oscillator ge control # frequency divider 1, which can be freely set by the microprocessor, is provided, so that a different number of support points or instantaneous values over a period can be reached. According to a further preferred embodiment of the invention provided that the unit for temporal address assignment one of the clock oscillator and frequency divider-controlled counter and that the unit for temporal Address assignment to another controlled by the clock oscillator and frequency divider Has counter and an adder. By the clock oscillator and frequency divider Controlled counters are initially saved in the buffer memory Time-controlled instantaneous values retrieved. Through the further counter and the adder can be variations of the stored waveform and interference current in particular Displacements of the two curves against each other and thus the beats, above all but variable beats can be achieved. According to a further preferred embodiment it is provided that the unit for the temporal address assignment is a further, has freely programmable memory. By storing a linear In the case of an interference current, the function is a reproduction of the stored waveforms reached, while when storing a non-linear function a non-linear one Shift of one of the two curves for interference current and in order to a change in the shape of the beat that deviates from the original shape can be achieved can.

Further advantages and features of the invention emerge from the claims and from the following description in which an embodiment of the invention for the interference current therapy is explained in detail with reference to the drawing. It shows: FIG. 1 a block diagram of the embodiment for interference current therapy the device according to the invention; Figure 2 is a more detailed circuit diagram, too for use in interference current therapy; and FIG. 3 shows a representation of the temporal Assignment of the instantaneous values of two output curves retrieved from the buffer for interference current therapy.

According to the block diagram of Figure 1, the inventive Apparatus initially has an input unit 11. There is also a clock generator 15 or an oscillator is provided, which generates the individual clock frequencies.

The core of the device according to the invention are shown in FIG Exemplary embodiment for the 1 interferential current therapy initially two intermediate stores 17 and 19 for specific curve shapes. Will not be interference current therapy but It goes without saying that only stimulation current therapy is carried out with a pair of electrodes only such a buffer is required.

To control the buffers 17, 19 or to retrieve data stored there Curves, or more precisely their instantaneous values, is a unit for the temporal assignment of addresses 21 provided by the microprocessor 13 taking into account a by the Clock generator 15 generated clock is controlled.

The buffers 17, 19 are each a digital-to-analog converter 23, 25, which contain the instantaneous values digitally stored in the intermediate memories convert it into an analog signal. The analog signal can then still over amplified by an amplifier (not shown) and then applied to the respective pairs of electrodes (also not shown) given for treatment.

From Figure 2 it can be seen that the input unit in addition to operating elements 31 in the illustrated embodiment, a program memory 33 and a data memory 35 has. In these memories are data or program elements; as well as algorithms saved, based on which, depending on the request entered via the control elements of the practitioner with the microprocessor digital representations of any desired Curve shapes can be generated. You will be in between.

17, 19 store the RAMs, i.e. random access memories with direct access, which can be read / write memories, cached and from there via the unit for the temporal address assignment 21 in a controlled manner Way.

The input unit also includes a timer 37 with which in on The duration of treatment can be determined in a known manner.

The clock generator 15 initially has a quartz oscillator 39 as a clock oscillator and also a frequency divider 41.

For a more detailed explanation, the buffers 17 are shown in FIG or 19 with Spl for curve 1 or output 1A1 and p2 for curve 2 or denotes the output 2A2. In particular, the central unit of the invention for the temporal address assignment of a device for interference current therapy is detailed in Figure 2; shown.

From the quartz oscillator 39 via the adjustable divider 41 is first a counter Zl controlled, which in turn, due to the counting process, the individual desired Instantaneous values for generating a desired curve shape from the memory Sp 1 and via the digital-to-analog converter 23 the output A1 and thus the associated Electrode pair supplies. For the shape of a sine curve, the analogue generated curve is in Figure 3 next to the number I for three oscillations at different times shown. T means a period of oscillation of curve 1, for example the voltage at the first pair of electrodes.

The counter reads the current one at time t, for example Voltage value w1 (Figure 3) associated digital value from memory Sp1, where this digital value is then converted into the analog voltage value w1. When counting through, at times t. the assigned voltage values w. generated until the counter at its final value t and the associated voltage m value w, which is equal to zero, has arrived, the counter is then reset and the counting process with reading out the individual voltage values again from begins again.

The counter Z I is also connected to the clock 37.

The counter I continues to be connected to the buffer store via an adder C Sp2 connected. If the adder z is not activated for addition, the memory Sp2 the curve shape stored there in the same way as the one stored in memory Sp1 Curve retrieved.

In particular, it would be with both memories after the counter ran out start counting again with the same period duration.

In order to be able to generate a different period in memory 2 in particular and thus being able to assign a different frequency to curve 2, the divider 41, which can be set by the microprocessor 13, a further counter Z II is controlled. By the counter Zli are freely and flexibly settable memory contents of the memory Sp3 fed to the adder S, causing a variation in the retrieval of the memory Sp2 for the second curve can be generated. For example, when storing a linear function in memory Sp3 a repetition of the beat waveform is achieved.

To change the shape of the beat, for example a non-linear shift of the second curve must be entered in memory Sp3, which then results in the change in the beat shape over the treatment time. By means of the device according to the invention in the illustrated embodiment Now the following has been achieved: Due to a selected switching of the control elements 31 are in the microprocessor 13 by from the program memory 33 and the data memory 35 recorded information instantaneous values of two identical or different Curves formed. First, then from each memory Sp1 and Sp2 based on a clocks generated by means of the quartz-stabilized oscillator 39 and the divider 41 at the same time such instantaneous values are called up for the waveform that are at the outputs Al the required curve shape, frequency and, with algebraic addition, the instantaneous values of the two resulting curves the required beat with the corresponding Beat frequency and generate the waveform of the beating. By means of the microprocessor 13 is so due predetermined information stored in the frame memory 33 and data memory 35 or software - which is not part of the concept of the invention - the hardware, such as it is the subject of the invention, initialized so that at the outputs Al and A2 the required curve shapes occur.

With the mentioned clock frequencies from the oscillator 39 and the divider 41, addresses are formed in the device according to the invention, under from which the corresponding instantaneous values for the curve formation are taken.

Assuming that the curve I over the entire treatment time should have the same shape, this is achieved by removing the memory Spl the instantaneous values assigned to the required curve shape periodically with a Period T can be called up. In curve II, the instantaneous values are after a Time n x T, which is essentially determined by the counter Zlr and the memory Sp3 is, reassigned and are used for a next period n (possibly also another n ') x T repeated periodically with this new assignment. This creates an interference beat curve, whose frequency depends on the n, where n is the number of periods of the medium-frequency Is the curve according to which the instantaneous values of curve II are reassigned. There n can be chosen as desired and in particular as large as desired, no matter how big low interference frequency possible. It can be any beat waveform can be generated by assigning the instantaneous values of curves I and II, which are just is arbitrary, is selected according to the required curve shape.

According to the invention, a high level of stabilization of the beat frequency is first achieved achieved, the memory overhead for permanent storage is kept low and yet a variety of different curve shapes, such as sinusoidal shapes, rectangular output signals or also sinusoidal, rectangular and even triangular Beat forms can be achieved with or without pauses.

The in the above description, in the drawing as well as in the Features of the invention disclosed claims can both individually and in any combinations for realizing the invention in its various Embodiments are essential.

Claims (6)

PATENT CLAIMS 1. Device for electrical stimulation therapy with at least a circuit with a pair of electrodes, at least one amplifier, a clock oscillator, a program memory and an input unit and a control unit, thereby characterized in that a microprocessor (13) as the central control and processing unit to generate desired waveforms and frequencies based on program memory, Input and control unit-related information and instructions are provided, that the microprocessor (13) has at least one buffer (17, 19 or Spl, Sp2) is assigned, in which the curve shapes (I, II) and frequencies in the form of instantaneous values can be temporarily stored, and that a frequency divider (41) and a unit (21) for temporal address assignment is provided, which is an output of the in the buffer (17, 19) temporarily stored instantaneous values of the curve shape (I, II) due to information required via the microprocessor (13) to create the curves guarantee. 2. Apparatus according to claim 1 or 2, characterized in that the unit (21) for temporal address assignment of at least one woman clock oscillator (15) or divider (41) controlled counter (Zl). 3. Device according to claim 1, in particular for interference current therapy, with at least two separate circuits and each associated pair of electrodes and associated amplifiers, characterized in that each circuit (A1, A2) a buffer (17, 19 or Spl, Sp2) for buffering the instantaneous values for the waveforms (I, I i) of the output voltages (w1, w ~, w) is assigned. 4. Apparatus according to claim 3 in conjunction with one of the preceding Claims, characterized in that the unit for temporal address assignment (21) a further counter (Z @) controlled by the frequency divider (41) and an adder (#) having. 5. Device according to one of the preceding claims, characterized in that that the or the intermediate memory (17, 19 or Spl, Sp2) from a RAM, so a Read-write memory, consists or consist of RAMs. 6. Device according to one of claims 4 and 5, characterized in that that the unit for temporal address assignment (21) has a further, freely flexible has programmable memory (Sp3).