FR2472799A1 - Analogue data memory for analogue and alphanumeric display - converts analogue data to digital form and displays on CRT at higher sweep rate for display with alphanumeric data - Google Patents

Abstract

Low frequency analogue medical measurements are gathered (11) then converted to a digital representation by an analogue to digital converter to be multiplexed (12) with numerical data. The multiplexed data is then passed to a central data display facility (13,14) and stored in memory to be reconverted back to analogue form (A) and repetitively applied to the vertical deflection amplifier of a cathode ray tube at higher sweep rate giving easy viewing. A sequence controller (S) controls the analogue display and alphanumeric display. The alphanumeric characters are formed from a character generator ROM in matrix form giving serial binary bits which control the intensity of the cathode ray tube to form the characters on the screen in sync. with the horizontal sweep and high rate vertical sweep produced by the sequence control when the alphanumeric area of the screen is reached.

Description

The subject of the present invention is a memory device ensuring the display of analog and digital information on the same screen.
In a certain number of applications, it is necessary to view both analog information and digital information. It is of course possible to use two different devices for these two types of information. It may nevertheless be desirable to have them on the same display element, both in terms of the compactness of the resulting device and in practical terms for the user; indeed, the device then presents a greater simplicity of appearance, which is particularly appreciated when the user is not a professional electronics engineer.

Furthermore, the display of parameters whose evolution is slow creates difficulties: if the speed of the display is that of the evolution of the parameter considered and that a display device is used without memory, we only get a very punctual vision of the value of the parameters at each instant, almost excluding tt, ut2, information on its evolution. To overcome this -difficulty, we use a device comprising memory or at the level from the display screen, either in the electronic circuit order
Finally, certain applications are made in an electromagnetically disturbed medium, which requires special precautions in the processing of analog information.
These different aspects are found in a certain number of applications, in particular in the case of the visualization of physiological parameters such as electrocardiogram, blood pressures, temperature, etc., and this on devices located in a hospital environment, ready for each patient. .

Different systems are known which use several screens, in particular separate screens for analog and digital information, which does not meet the criteria of compactness and convenience for medical users. In addition, this solution is expensive. Furthermore, with regard to the display of slow parameters, it is known to use cathode ray tubes with memory for the display device itself, which have the drawback of being very expensive; it is also known to use in the electronic control system a set of shift registers with M positions looped over themselves, in number equal to the number (N) of display lines, which gives a matrix of M x N points; this results in a bulky and therefore expensive electronic device.

The present invention relates to a display device meeting these various requirements and at a low cost.

For this purpose, this device mainly comprises - a display element, comprising a cathode tube
dique; - a first set, ensuring the processing of in
analog training, including:
analog to digital converter, memory
digital and a digital-to-analog converter this set receives the analog information and supplies it to the vertical amplifier of the cathode ray tube, and this at a frequency sufficient to obtain, thanks to the retinal persistence, an impression of permanence of the image - a second set ensuring the processing of
alphanumeric information, including
memorization of information and its presentation
tation in the form of alphanumeric characters ;;
this set receives the alphanumeric information
and supplies them to the Wehnelt circuit of
cathode ray tube ; - a sequencing device controlling the
previous sounds as well as the amplifiers
horizontal and vertical of the tube, so that a
share be assured the sequencing of information
to the cathode ray tube and on the other hand
the information is stored in the two
sets at times when are not taken
this information to the tube.

Other objects, characteristics and results of the invention will emerge more clearly from the following description, illustrated by the appended drawings which represent FIG. 1, a general diagram of the device according to
the invention - Figure 2, a diagram illustrating the sequence
cement of the display of the different informa
tions - Figure 3, the diagram of an embodiment
of the sequencing device used in the
device according to the invention - Figure 4, an embodiment of the assembly
analog information processing used
in the device according to the invention - Figure 5, the diagram of an embodiment
of the information processing set al
phanumeric, used in the device according to
the invention.

 In these different figures, the same references relate to the same elements.

 Figure 1 is therefore the overall diagram of the device according to the invention.

 In this figure, there is shown a first assembly, marked 11, which carries out the acquisition of information of the analog type which is intended to be displayed on the screen of a display element 18, such as a cathode ray tube, this information-being received on entries identified 10.

This information can be, as mentioned above in the case of medical applications, physiological functions such as electrocardiogram, blood pressure, respiration, pulse, etc. The realization of the acquisition circuits constituting the assembly 11 is for example described in the French patent application No. 79 29 156 filed in the name of the Compagnie Générale de Radiologie (CGR).

 This analog information is directed on the one hand to a set A of processing circuits and on the other hand to circuits 12 for multiplexing and digitizing this information.

Indeed, it is necessary to process this information, for monitoring purposes for example, by comparing it to predefined thresholds or to values previously reached. This monitoring can be carried out using a circuit 13, which can be constituted either by a set of logic circuits, or by a programmed computer such as a microprocessor. The circuit 13 transmits its results to a set N for processing alphanumeric information and possibly, via an output referenced 14, to a centralized surveillance system, processing the information originating from several diseases, in the case of medical surveillance.

The set A processing the analog information controls an amplifier 15, called the vertical amplifier because it controls the vertical deflection of the light spot in the cathode ray tube 18. The set N controls a set 17 which is the control circuit of the electrode
Wehnelt of tube 18, in order to cause the extinction of the spot when necessary.

 The assembly is controlled by a sequencing device S, which receives external input from an input 19, for example from an operator, which sends orders corresponding to elements 13, 15, 16, A and N. This sequencer S has for the function of ensuring the sequencing of the information intended for the tube 18 on the one hand, and on the other hand of ensuring the control of the memorization of the information in the sets A and N and the reading of the information memorized in these same sets , at different times. The role of the sequencer S will be better understood with the aid of FIG. 2.

On the left side of FIG. 2, a first signal, referenced H, which is the signal, has been represented as a function of time (t).
supplied by the horizontal amplifier 16 - a second signal, referenced V, which is the signal
supplied by the vertical amplifier 15; - three control signals 21, 22 and 23 on which
it will be returned in the following description.

 These different signals have the same time axis (t) plotted on the abscissa.

The right part of the figure illustrates the screen of the cathode ray tube twice: the first time (24), this one is placed vertically in order to illustrate the displacement of the spot along the axis
Ox, due to signal H; the second time (25), it is placed horizontally to illustrate the displacement of the spot along the axis Oy, due to the signal V.

For greater clarity of description, the various signals are described in the case where information shown by way of example is displayed on the screen on the right-hand side of the figure, namely - a first jumper display of a analog signal A1, occupying approximately 2/3 of the screen of a
vertical line 29 to vertical line 28 - a second analog signal A2, also displayed
as a jumper, coming under the signal A1 :: - two horizontal reference lines, intended
to facilitate reading, framing the A2 signal
and referenced 26 and 27; - four sets of affi digital information
on the right side of the screen, between the
line 28 and a vertical line 30, one at the
below the others, and referenced N1 to N4 - two digital information displayed in the par
left tie of the figure, between line 29 and a
vertical line 31, on either side of the signal
A2 and referenced N and N6.

 The alphanumeric characters displayed in zones N1 to N6 can have variable sizes, that is to say occupy all or part of the reserved zone; an alphanumeric zone can be used to display a single parameter or several parameters.

 The evolution of the signals H and V is as follows: from the initial instant (0) to an instant t11 the signal H is zero, which corresponds to a positioning of the spot vertically at the place desired to describe the signal A1; from time tl to time t2, the signal H is a sawtooth allowing the spot to move to line 28, in order to display the signal A1; from time t2 to time t31 the spot returns to the vertical line 29, this return being used to draw the line 27; from time t3 to time t4, the signal H is zero, which allows vertical positioning of the spot along line 29 for the tracing of signal A2; from time t4 to time t5, signal H allows the spot to move towards line 28 so that signal A2 is traced; from time t5 to time t6, signal H allows the spot to be moved to line 30 for the display of alphanumeric information; during this period, the vertical amplifier supplies a very tight sawtooth signal V so as to carry out a scanning in vertical lines very fast and to obtain a good definition and a good readability of the digital information; this is symbolized by a few saw teeth in the middle of the area t5 to t6; from instant t6 to instant t7, the signal H allows the spot from line 30 to return to line 29, this duration being used from an instant tg which corresponds to the passage up to line 28 for draw line 26; from time t7 to time t8, the spot is positioned for the recording of alphanumeric information in the areas N5 and N6; in the same way as between the instants t5 and t6, the signal H causes the deflection of the spot from the line 29 to the line 31 for a duration extending from the instant t8 to an instant t10 which is identical to the instant origin of the diagram, while the vertical amplifier provides a rapid sawtooth signal, diagrammed in the same way. The period tg of the display, that is to say the duration separating the instants to and tlo, is such that an impression of permanence of the image is ensured, thanks to the phenomenon of retinal persistence; for example, this period is of the order of 20 to 25 ms.

FIG. 3 is the diagram of an embodiment of the sequencing device represented in FIG. 1. It will be recalled that the purpose of the sequencer S of FIG. 1 is, on receipt of external commands (19), on the one hand to ensure the sequencing of the information towards the display device, illustrated by FIG. 2, and on the other hand to control the recording in memory of the analog information and of the alphanumeric information, only at the instants when these are not read and directed for display towards the horizontal and vertical amplifiers and the Wehnelt circuit of the cathode ray tube.

In the embodiment described in FIG. 3, the sequencer is mainly constituted by an arithmetic and logic unit S1 (U.A.L.), a microprogrammed memory S2 and a set of buffer memories S4 to 87.

 The function of the buffer memories is to record the information intended for the sequencer in the input direction and to keep it available to the arithmetic and logic unit S1, and in the output direction, to ensure the storage of the orders of the sequencer coming from the unit S1 and which are taken up by the other elements of the device when these are available. The information inputs to the sequencer correspond to the command shown diagrammatically by an arrow 19 in FIG. 1; these are the various operating commands that the user of the device can display and that it is up to the sequencer to carry out, for example, the choice of one of the physiological functions to be displayed on one of the analog channels shown as an example in Figure 2 (A1 or A2), or the speed of the display or the freezing of the information displayed, that is to say until the user sends a counter-order, the information displayed at a determined time is no longer modified, only the maintenance of the image being ensured, etc. In the direction output of the information to the other elements of the device, the sequencer comprises a buffer memory S5 recording information intended for the horizontal and vertical amplifiers, as well as the sequencing commands intended for the alphanumeric circuit N. The last two buffer memories S6 and S7 are assigned to the information intended for set A of FIG. 1.

 The sequencer therefore comprises the arithmetic and logic unit Slr which can be produced for example using a sequential lbit microprocessor of the MC 14 500 B type, in connection with a memory which can be produced for example using 'a PROM type read-only memory containing a sequencing firmware as defined in FIG. 2.

 The memory S2 is connected on the one hand in parallel to the unit S1 (thick line in the figure) in order to transmit the instructions to be executed to it and on the other hand1 also in parallel (thick line in the figure), to each of the buffer memories S4 to S7 to which it provides addresses where the received data are stored (address connection 31 to the buffer memory S4) where supplied by it (address connections 32, 33 and 34, respectively to the buffer memories Sg , S6 and S7).

In the case where the unit S1 is produced simply by means of a sequential microprocessor of the type mentioned above, the sequencing device must also comprise a few auxiliary circuits constituting a waiting loop whose role is to allow get rid of sequentiality, as well as a counter S3 and a clock Sg: the waiting loop S8 is addressed by the memory S2, the counter S3 addresses the memory; : the clock Sg controls the unit S1 and the counter S3 and receives the command from the waiting loop I1 it should be noted that this clock constitutes the time base of the entire device; it must therefore send a synchronization signal to the other clocks likely to exist in the various elements of the device of FIG. 1, in particular the microprocessor 13, which is represented diagrammatically in FIG. 3 by an arrow 35.

 FIG. 4 is the diagram of an embodiment of the assembly A of FIG. 1, processing the analog information. For greater clarity, this description is made in the particular display case shown in FIG. 2.

On this diagram we find successively, receiving analog signals coming from block 11 of FIG. 1 - an element 40 ensuring the interface between these information
analog mations and the rest of set A,
essentially fulfilling an adap function
tation of the input signals - a multiplexing device 41, receiving the
different analog signals from
the interface 40 in parallel and performing the se
lection of the signals to be displayed among the different
high input signals, on external control
of the operator via the selector S, and the multi
plexing of these signals, using a commuta
analog counter, so as not to provide the
ment as a series type information ;; - an analog-digital converter 42, rece
before the analog signal from the mul
tiplexer 41, performing a sampling and a
digitization of the signal, which it supplies in parallel on n bits (thick line on the -figure) - a buffer memory 43, receiving the digital signal
previous risk, always in parallel (line
thick) ;; - a set of memories 45 and 46, respectively
assigned to each of the two display channels
analog A1 and A2, each accompanied by a
address selector, respectively 44 and 47, re
receiving information from the me
buffer memory 43 in parallel on n bits - a buffer memory 49, receiving the information
parallels coming out of memories 45 and 46 for
display element nation - a 50 digital to analog converter receiving
digital information in parallel on n
bits, coming from the buffer memory 49 - a mixer 51, receiving the analog information
serial gics from converter 50 and
ensuring the filtering of these signals, as well as their
mixing using an analog switch, in order to position them in relation to the reference lines 26 and 27 (FIG. 2) and supplying the signals A1 and A2 to the vertical amplifier 15 of FIG. 1.

 The assembly also includes a buffer memory 48, connected in parallel to the output of memories 45 and 46; it is intended for external devices using the information contained in memories 45 and 46, for the purposes of recording and centralized monitoring, carried out for example using repeaters. The buffer memory 48 therefore contains all the analog information intended for display, but this in digital form. I1 is known to forward this buffer memory by a demultiplexing device and digital-analog converters, themselves followed by filters, in order to obtain two different analog channels, carrying information to external devices. Another solution consists in using the this information is available in digital form in parallel on n bits: we then connect a device serializing the information and transmitting the information asynchronously to the external device. If the latter is at a certain distance, it is necessary to add transmission elements such as optical fiber or differential device providing the signal on a pair of connections, these closing for example on an optical coupler to achieve a electrical isolation. Such a mode of transmission notably has advantages of simplicity and reliability, the latter being linked to the fact that the information transmitted is digital.

These different elements are all controlled by the sequencer S which, as mentioned above, has the function of controlling the recording in memories 45 and 46 of information relating to the analog signals to be viewed only when not carried out in these same memories a reading to the display element.

This synchronization carried out by the sequencer S is illustrated by way of example in FIG. 2 by the control signals 21 to 23 for the control of the analog-digital converter 42. The signal 21 represents the orders for converting the analog information of the channel 1 sent by the sequencer S to the converter 42; these orders are, for example, in the form of impulse signals. Between the instants tl and t2, a conversion order has been represented, between t2 and t3 another, between t4 and t5 another, between t5 and t6 four orders, and finally between t8 and t10 two conversion orders. Similarly, the control signal 22 represents the conversion orders received by the converter 42 for channel 2. Two orders are represented between tl and t2, two others between t4 and t5, three between t5 and t6, one between tg and t7 and finally one between t8 and tlo. As these conversions are carried out, they are recorded in the buffer memory 43. The control signal 23 represents, in the same form, the orders for copying from memory 43 into the respective memories of the two channels 45 and 46 , these copies being preceded by the copying of the contents of the memories into the output buffer memory 49; these copy orders occur between time t2 and time t3, that is to say when line 26 is drawn, therefore where memories 45 and 46 are not read by the element of display, as well as for the duration going from instant t5 to instant t6 where the digital display of the right part of the screen is carried out and therefore where the memories are not addressed in reading either, and finally between times t8 and t10 where a digital display is again performed, on the left side of the screen this time (zones N5 and N6).

Figure 5 is the diagram of an embodiment of the assembly N of Figure 1, ensuring the processing of alphanumeric information.

 This assembly includes a memory 55 which represents a matrix of image points and which supplies this information to the Wehnelt circuit 17, this information being of the binary type, namely illuminated point or black point.

 The assembly also comprises an alphanumeric character generator 56, which has the function of converting the binary signals received into a matrix of binary points, in order to fill the preceding matrix 55, according to the instructions of the assembly 13 of FIG. 1, via a buffer memory 52; the assembly 13 provides the code of the stere character, its position, if necessary its size and its presentation (positive or negative). The generator 56 supplies this information to the memory line by line, indicating the black or white points of the character stored in memory.

The set 13 also supplies the start addresses of the character, still via the buffer memory 52. These addresses are supplied to two address-generating counters, one for the vertical address (54 in the figure) and the other for the horizontal address (53 in the figure).

 Finally, the assembly 13 indicates to the sequencer S, still via the buffer memory 52, the beginning of a character. The sequencer S also controls the incrementation of the counters 54 and 53.

Claims (6)

R E V E N D I C A T I O N S  1. Memory device for viewing analog and digital information on a cathode ray tube, characterized in that it comprises - a first assembly (A), ensuring the processing  analog information and comprising: a analog to digital converter (42), a m  digital moire (45, 46) and a bare converter  analog-digital (50), this set (A) receives  selling analog information and providing  these to an amplifier (15) connected to the cir bends of vertical deflection of the cathode ray tube  (18), at a frequency sufficient to ensure the  image permanence - a second set (N) providing processing  alphanumeric information, realizing the met  moralization of information and its presentation in the form of alphanumeric characters, this in seems to receive alphanumeric information and supplying them to the Wehnelt circuit of the tube cathodic (18); - a sequencing device (S) controlling the  two previous sets (A, N) and the amplifiers connected to deflection circuits  horizontal (16) and vertical (15) of the tube (18),  so that on the one hand the sequencing is assured  information intended for the tube (18) and  on the other hand, the information is memorized in the two sets (A, N) at the times when  this information is not collected at destination  of the tube (18). 2. Device according to claim 1, characterized in that the first assembly (A) further comprises two buffer memories (43, 49) respectively at the input and at the output of the memory (45, 46), the first (43) receiving the output signal from the analog-digital converter (42) and transmitting it to the memory (45, 46) on the control of the sequencing device (S), and the second (49) receiving the output signal memory (45, 46) and supplying it to the analog digital converter (50) on command of the sequencing device (S). 3. Device according to claim 2, characterized in that the first assembly (A) further comprises a third buffer memory (48) receiving the output information from the memory (45, 46) and providing it, on command of the device sequencing (S), to external devices for copying the displayed information, the information which is transmitted to these external devices being in digital form. 4. Device according to claim 3, characterized in that the information which is transmitted to the external devices is in serial digital form.  5. Device according to one of the preceding claims, characterized in that the second set (N) comprises a buffer memory (52) receiving the alphanumeric information to be displayed, or characters, an alphanumeric character generator (56) converting a character in a binary point matrix, a vertical (54) and horizontal (53) address generator providing the coordinates of each character, and a second memory (55) receiving at the addresses indicated by the address generator the matrix supplied by the character generator (56).  6. Device according to one of the preceding claims, characterized in that the sequencing device (S) comprises: an arithmetic and logic unit (S1) controlled by instructions recorded in a third memory a set of buffer memories (S4- S7), these registering the information intended for the sequencing device (S) or supplied by the latter, to the addresses provided by the third memory (S2), a clock (Sg) ensuring the synchronization of the components of the device to memory, and a counter (S3) ensuring the execution of the instructions.