FR2536863A1 - WAVEFORM VISUALIZATION APPARATUS, AND ASSOCIATED METHOD - Google Patents

Abstract

THE WAVEFORM DISPLAY APPARATUS INCLUDES A DISPLAY MEANS, FOR EXAMPLE A CATHODIC-RAY TUBE32, AN AMPLIFICATION MEANS, FOR EXAMPLE A VARIABLE GAIN AMPLIFIER30 AND A DELAYED SCAN CIRCUIT26, TO AMPLIFY THE D-SHAPE '' SIGNAL WAVE DISPLAYED ON THE DISPLAY MEDIA, A DISPLAY POSITION CONTROL MEDIUM, FOR EXAMPLE A DIGITAL-ANALOGUE CONVERTER22, A DIFFERENTIAL AMPLIFIER24, AND A POINTER MEMORY52, ALLOWING TO CONTROL THE POSITION OF THE VISUALIZATION WAVE DISPLAYED ON THE DISPLAY MEDIUM, AND A PROCESSOR58 WHICH CONTROLS THE MOVEMENT SPEED OF THE DISPLAY POSITION OF THE SIGNAL WAVEFORM AS A FUNCTION OF SAID AMPLIFICATION MEDIUM.

Description

2536863-

  The present invention relates to a display device

  waveform sation that displays the waveform of a signal

  and amplifies the displayed waveform.

  Oscilloscopes and logic analyzers are measuring instruments that contain a waveform display device for displaying the waveform of an input signal and the waveform of a synchronization signal logic in YT (time amplitude) mode, and these instruments are used

  to measure various characteristics of electronic devices.

  To measure in detail the waveform of a signal displayed on the display device, it is necessary to amplify the waveform displayed along the time axis or amplitude, '

depending on the purpose of the measurement.

  A conventional waveform display device increases the amplitude of a waveform signal or a scanning signal (sawtooth waveform or waveform in

  steps) by increasing the gain of a green amplifier

  tical or horizontal to increase the amplitude or time axis of the displayed waveform If you add a variable level of direct current to the waveform signal to move a display position of the waveform signal, the direct current level is amplified at the same time as the wave form signal When the direct current level is modified in the case of an amplification of a value equal to the value of an unamplified case, the displacement value of the amplified displayed waveform is greater than that corresponding to the unamplified case The speed of displacement of the amplified displayed waveform is constant with respect to the form signal d whole wave; however, the speed of movement increases with respect to the display means if the DC level is varied by the same value. Thus, it is necessary to adjust

  a display position gently and it is difficult to display

  expensive a desired waveform part into a desired part of the

display medium.

  The conventional waveform viewing apparatus, in particular the oscilloscope, has a delayed scanning function so that the desired part of the signal waveform can be viewed by amplifying the time axis.

  this delayed scanning function, a scanning signal A (ba-

  main layout) is compared to a DC level for the purpose of determining a delay time (the desired part), and a sweep signal B (delayed sweep) begins after the delay has elapsed. position of the displayed waveform of the scanning B by adjusting the level of direct current, the speed of movement relative to the display means may become high when the ratio (or the difference) of the scanning speeds A and B becomes large if we modify the level of direct current by the same value It is therefore difficult

to adjust the display position.

  The conventional waveform display device displays a pointer making it possible to measure the voltage or the time of a desired point of the displayed waveform When the displayed waveform is amplified in the manner described above , the pointer display movement speed may become large relative to the display means, and the measurement may become

inconsistent.

  It is therefore an object of the invention to provide an apparatus

  waveform display that maintains substantially

  aunt the speed of movement of a waveform or pointer displayed with respect to the display means even if the waveform

displayed is amplified.

  Another object of the invention is to propose an apparatus

  waveform display that changes the speed of movement

  ment of a waveform or a pointer displayed in relation to the entire waveform as a function of an amplification rate in order to keep the speed of movement substantially constant

  relative to the display means, regardless of the amplification rate

  fication. Another object of the invention is to propose a method

  waveform display to keep sensitive-

  constant with respect to the display means the speed of

  moving a waveform or a visualized pointer> independent

especially the amplification rate.

  These objects of the invention, as well as other objects, are accomplished by controlling the speed of movement of a display position relative to the entire waveform of a signal as a function of the amplification rate A processor calculates the amplification rate of a displayed waveform, and display position control means slows down the speed of movement of the display position relative to the form waveform of the signal under control of the output signal of the processor when the displayed waveform is amplified Thus, the speed of movement of the displayed waveform or pointer is substantially constant with respect to the display means, independently of display amplification, and it's easy to control the

  display position In this description, the expression "rate

  amplification "means both the ratio and the difference of the unamplified waveform and the amplified waveform

in time or in amplitude.

  The following description, intended for illustration

  of the invention, aims to give a better understanding of its characteristics and advantages; it is based on the appended drawings, among which: FIG. 1 is a schematic diagram of a digital oscilloscope with an embodiment of the invention;

  Figure 2 shows a flowchart for explaining

  quer the operation of Figure 1; -

  Figures 3 A, 3 B 1, 3 B 2, 3 C, 3 D 1, 3 D 2, 3 E 1 and 3 E 2 show detailed flowcharts to explain the

operation of Figure 1; -

  Figure 4 is a block diagram of part of a second embodiment of the invention; Figure 5 is a block diagram of part of a third embodiment according to the invention; and Figure 6 is a block diagram of part

  of a fourth embodiment according to the invention.

  We refer to FIG. 1, on which -is represented

  felt a block diagram of a digital oscilloscope (device

  waveform memorization) using a visualization device

  waveforms according to the invention An input signal applied to an input terminal 10 is suitably adjusted in amplitude by an attenuator 12, and the signal thus adjusted is

  applied to a preamplifier 14 The attenuation rate of the

  nuateur 12 is controlled as a function of a digital signal coming from an omnibus line 16 comprising data, address and control lines A trigger circuit 18 detects a trigger point of the output signal of the amplifier 14 in based on trigger information from bus line 16, and circuit 18 applies a trigger signal to bus line 16 and to scan circuit A Scan circuit A begins to produce a main scan signal

  and a non-suppression signal in response to the trigger signal

  ment, the speed of the main scanning signal being controlled as a function of a scanning speed instruction coming from the bus line 16 A digital-analog converter (DA) 22 produces an analog signal corresponding to a digital signal coming from the bus line 16, and the converter 22 can be

  for example an integrated circuit of the "ITS 80 141" type.

  logic is compared to the main sweep signal from the circuit

  cooked 20 scan A by a comparator (differential amplifier

  tiel) 24 which produces a delayed trigger signal from a circuit

  cooked 26 scan B In response to this trigger signal, scan circuit 26 B begins to produce a delayed scan signal and a non-cancellation signal depending on a

  sweep speed instruction from bus line 16.

  Since a delay time, namely a display position, is

  determined by the D-A converter 22 and the differential amplifier

  tiel 24 in the delayed scanning mode (B), these blocks 22 and 24 act as display position control means The scanning circuit 26 B acts as an amplification means since

  amplifies the time axis of a displayed waveform A switching

  28 selects the scanning circuit 20 or the scanning circuit 26, B, respectively in the main scanning mode (A) or the delayed scanning mode (B) The scanning signal selected by the switch 28 is applied to a plate deviation

  horizontal of a cathode ray tube (CRT) 32 via a

  mutator 29 and a horizontal amplifier 30, where the TRC 32 is the display means The amplifier 30 can amplify the time axis of the displayed waveform by increasing its gain according to an instruction from the line omnibus 16, so that the variable gain amplifier 30 can operate

  amplification means A circuit 34 of Z axis (intensity control

  site) receives non-suppression signals from circuits

  20 and 26 and controls the electron beam of the TRC 32.

  The output signal from amplifier 14 is

  applied to a vertical deflection plate of the TRC 32 via the

  middle of two switches 36 A and 36 B grouped together; and a vertical amplifier 38, or it is applied to an analog-digital converter MA & -N) 40 via the switch -36 A. The converter AN 40 samples the analog output signal coming from the amplifier 14 under command d a clock signal coming from a generator 42 of clock signals, and the converter 40 transforms, the sampled signal into a digital signal The converter AN 40 can be an integrated circuit

  of the type "TDC l O Ol J" The frequency of the clock signals of the general

  The clock signal generator 42 is controlled by an in-

  clock transmission from the bus line 16 A circuit 44 for memorizing waveforms stores the digital signal coming from the AD converter 40 as a function of a sequentially varying write address signal which comes from the bus line 16, in the writing mode In the reading mode, the digital signal stored in the circuit 44 for memorizing waveforms is read under control of a signal of address sequentially varying, which comes from a generator 46 d reading address, and the digital signal read is transformed into an analog signal by a converter NA 48, which can be an integrated circuit of the type "AD 7528" The address generator 46 can be a counter which counts the signal of clock An analog signal coming from the converter NA 48 is applied to the vertical deflection plate-of the TRC 32 via the switch 36 B and the vertical amplifier 38 A converter DA 50 transforms the address signal coming from the address generator 46 into an analog signal to produce a sweep signal (staircase waveform) which is applied to the horizontal deflection plate of the TRC 32

  via switch 29 and horizontal amplifier 30.

  Each address of a point storage circuit 52

  tor corresponds to a particular address of the memo circuit 44

  waveforms, and a predetermined signal, for example "1", coming from the bus line 16 is stored in an address of the memory circuits 52 which corresponds to a position of the pointer In the reading mode, the generator address 46 delivers the same address signal to the storage circuits 44 and 52 and to the converter NA 50, and the pointer storage circuit 52 applies the output signal to the address generator 46

  when the pointer position is addressed When the general-

  address generator 46 receives the output signal from the pointer memory circuit 52, the address generator 46 maintains

  the address signal valid at this time for a pre-

  determined, i.e. the counter stops counting.

  Then, the address generator 46 again changes the address signal sequentially Since the output signals of the

  N-A 48 and 50 converters are maintained for the pre-

  determined at the pointer position, the electronic beam of the TRC 32 stops at the pointer position of the waveform displayed for the predetermined duration so as to modify the intensity The intensity modulation point corresponds to the

  pointer superimposed on the waveform displayed The general

  address erator 46 and pointer storage circuit 52

  act as display position control means per-

  putting to control the pointer display position.

  An indicator 54 displays the scanning delay time B. the voltage existing at the pointer position, etc., as a function of a signal from the bus line 16 A keyboard 56 connected

  on the bus line 16 acts as a personal input device

  setting various points of the setting for the attenuator 12, the trigger circuit 18, the scanning circuit 20 A, the D-A converter 22, the scanning circuit 26 B, the amplifier

: *: 2536863

  horizontal 30, the generator 42 of clock signals and the circuit

  cooked 52 pointer memory A central processing unit

  ment (UCT) 58 connected to the omnibus line 16 is for example a microprocessor of the "Z 80" type> and it performs various commands and arithmetic operations using a direct access memory, or random access memory, (MEV) 62, operating of temporary memory, according to the program stored in a fixed memory, or read only memory, (MEM) 60 The microprocessor "Z 80" is completely described in TZ 80 / Z 80 A CPU Technical Manual "and" Z 8400 / Z 80 CPU Product Specification ", published by Zilog As described below, V'UCT 58 acts as a processor making it possible to obtain the rate (ratio or difference) of the scanning speeds A and B - under command of the program contained in the MEM 60

  As will be understood from the description

  given above, the switches 3 '6 A and 36 B connect directly-

  the amplifiers 14 and 38 and the switch 29 positions the switch 28 in the real time mode, so that the instrument of FIG. 1 operates in the same way as a conventional oscilloscope. In the storage mode, the switches 29, 36 A and 36 B select different terminals from those corresponding to the real time mode It should be noted that the elavier-56 has right and left keys used to move the waveform or

  the pointer displayed to the right or to the left.

  FIGS. 2 and 3 A to 3 E present flow charts making it possible to explain how the position of display of the waveform or of the pointer displayed in the display device is controlled.

  visualization of waveforms of figure 1 We suppose that-

  the device of figure 1 visualizes a waveform of a signal

  on the TRC 32 in real time mode or storage mode.

  On the flowcharts, 'UCT 58 performs processing and

  determinations according to the program contained in the ME% 60.

  FIG. 2 is a complete flowchart of the position control In a step 70, the UCT-58 determines whether the current mode is real time mode (delayed scanning is possible) or storage mode (the pointer can be display), and the CPU 58 also determines whether or not the display is magnified, i.e.

2536863 -

  if the delay mode has been chosen or if the gain of amplifier 30 has been set to a large value If the display is amplified, the CPU 58 calculates the amplification rate (ratio or difference)

  and sets a travel speed as a function of the amplification rate

  The resulting movement speed slows down relative to the waveform of the signal when the amplification rate is large, and a large value of the movement speed means that the movement is slow. The movement speed value

  is loaded, as an initial value, into a counter of 1 CPU 58.

  When the right or left key (the position key to move the displayed waveform or pointer) has been pressed, the display position moves by a predetermined value in the direction determined by the key pressed Once this movement has been completed, a step 72 is followed. Step 70 will be described more fully in relation to FIGS. 3 A a

3 E 2 below.

  In step 72, the integrated counter of the CPU 58 decreases (counts down) by one the count value. The CPU 58 determines whether or not the content of the counter is less than or equal to zero, i.e. say whether the speed of movement is maximum or not, in step 74 If the content is not less than or equal to zero, the CPU 58 returns to step 72 If the content is less than or equal to zero, there is connection to a step 76 Thus, steps 72 and 74 are repeated until the content of the counter becomes less than or equal to zero in order to increase the speed of movement to the maximum as and when time elapses In step 76, V'UCT 58 determines whether or not the pointer mode has been positioned during step 70 A step 78 is followed if this is the case (yes), or a step 80 is followed if it is not (no) In step 78, i'UCT 58 returns to step 70 if the pointer mode is currently selected, or else the processing stops if it is not the case In the step at 80, the processing stops if the scanning mode A has been selected, or else step 70 is followed if this is not the case In other words, when the pointer mode was initially selected, and this mode has been canceled, processing is taking

-2536863

  9, end via steps 76 and 78 since it is not necessary to move the pointer for an amplified display When the scanning mode A has been chosen, step 80 leads to an end, since

  the scanning mode selected is not the delayed scanning mode.

  (display amplification) The processing returns to step 70, coming from step-74, in the only case where the position

  display is moved to amplified display The processing time

  For example, step 72 is 10 ms.

  As described above, when the speed of movement

  ment has a high value, it takes a long time in steps 72 and 74 for the content of the counter to cancel, and the speed of movement of the display position is slow compared to the waveform of the signal Since the value of the speed of

  displacement depends on the amplification rate, the displacement speed

  The display position is substantially constant with respect to the TRC 32, regardless of the amplification rate, and it is easy to adjust the display position. Step 70 will be discussed again in relation to FIGS. 3 A to 3 E 2 In a step 82 of FIG. 3 A, the CPU 58 determines whether the two right and left keys of the keyboard 56 are pressed or released When the two keys are released

  (not pressed), the displacement value and the displacement speed-

  ment of the display position are set to zero in a step 84,

  and the processing returns to the flowchart of figure-2, that is

  i.e. step 72 is followed The value and speed of movement

  ment are memorized in the MEV 62 Step 84 fixes the initial condition relating to the following displacement of the display position,

  when a first condition is transformed into a second condition

  editing, the first condition being that at least one of the right and left keys is pressed and the second condition being that the two keys are not pressed When at least one of the keys is pressed, a step 86 is followed and 1 'UCT 58 determines whether the two right and left keys are pressed or not If the two keys are pressed, a step 88 is followed and the processing returns to the flowchart of FIG. 2 after fixing of the parameters according to the mode chosen In d In other words, when the two keys are pressed, the display position cannot be moved However, the pointer-is moved to the center of the waveform displayed in the pointer mode, and the instant at which the two keys were pressed is considered a benchmark for the delay time of the delay mode. According to the invention, it is important that one of the keys is

  pressed In this example, a step 90 is followed.

  In step 90, V'UCT 58 determines whether the value of

  display displacement stored in MEV 62 is or is not zero.

  When the displacement value is zero, the display has not been moved after the right or left key has been pressed, i.e. the first displacement of the display position has not yet started in step 70 In this case, a step 92 fixes the displacement value at "50" (the minimum speed) When the displacement value is not zero, a step 94 fixes the

  travel speed at zero (maximum speed) As above

  above indicated, the speed of movement corresponds to the prepositioned value of the counter of 'UCT 58, and the speed is smaller the higher the value. Thus, steps-90 to 94 set conditions such that the movement initializes will at very slow speed Such an operation is useful for

  fine adjustment of the display position, since the display position

  chage is moved from the minimum value when the key has been temporarily pressed (during a period during which the counter integrated in 'UCT 58 has counted to 50) A step 96 is followed after steps 92 and 94, o the CPU 58 determines whether the cursor mode has been selected or not The flowcharts in FIGS. 3 B 1 and 3 B 2 are followed (B in FIG. 2) if the pointer mode has been selected> and the flow diagram in FIG. 3 D is

  monitoring (D in Figure 2) if this is not the case.

  In the pointer mode, the CPU 58 determines whether or not the movement speed is "50", that is to say if the movement of the display position was carried out initially, in a step 98 of the figure 3 BI When the displacement has been carried out initially, a step 104 is directly followed in order to prevent

  that the travel speed setting point be modified.

  11 i A step 100 is followed after the first displacement, and V'UCT 58 determines whether the amplification mode has been chosen or not, that is to say

  whether or not the gain of the horizontal amplifier 30 has been increased.

  If the amplification mode has been chosen, a step 102 is followed ,.

  during which the speed of movement is fixed at a

  value, for example "5", based on the increased gain of the amplifier

  tor 30 In the mode without amplification, a step 104 is followed in order to maintain the speed of movement at the 'value "O" fixed in step 94 The CPU 58 acts as a processor allowing

  '' calculate the amplification rate in steps 100 and 102.

  In a step 104 ′, UCT 58 determines whether or not the input signal is stored in the waveform storage circuit 44, since the pointer mode is only available when the waveform stored in the circuit 44 for storing waveforms is displayed on the TRC 32 Then, the processing returns to the flowchart of FIG. 2 when the input signal is not stored, and a step 106 is followed in the only case o the input signal is stored The CPU 58 determines whether or not the right key of the keyboard 56 is pressed in step 106, and a step 108 in FIG. 3 B 2 and the flowchart in FIG. 3 C are respectively follow if this is the case (W in FIG. 3 B 1) and if this is not the case (C in FIG. 3 B 1), In step 108 of FIG. 3 B 2, 'UCT 58 determines whether the speed of movement is zero or not A step 110 is followed in the case where the speed of movement is zero This case

  is not that of the first shift or the amplification mode.

  When the speed of movement is not zero, that is to say in the case of the first movement (the speed of movement is

  "50") or in the case of amplification mode (the speed -of movement-

  ment is "5"), step 112 is followed In this embodiment, the display area of the TRC 32 is divided into 1024 positions on the axis

  of time, and the area includes the display positions "01 'to" 1023 ".

  Thus, the memory circuits 44 and, 52 respectively store

  1024 data, and each address corresponds to a position -

  'particular display The CPU 58 determines whether the present position of the pointer is less than "1021" with reference to the information 12 stored in the storage circuit 52 during a step 110 If the result of the determination is "yes", a step 114 is followed in order to move the pointer by three steps to the right (three display positions divided) If the result is "no", a step 116 is followed in order to move the pointer to the position display "1023 (right end) Since

  step 110 is followed when the display position of the pointer

  tor is moved with high speed (maximum), the speed of movement is zero and steps 70 to 78 of figure 2 are repeated after a return to the flowchart of figure 2 once the pointer has been moved in the step 120 (which will be discussed below) If the pointer movement value for a process in step 70 is small, the movement speed is slow However, the movement speed is brought to

  increase by increasing the displacement value of the pro-

  stop considered in step 114 When the display position is moved three steps to the right in a case where the present pointer position is greater than or equal to "1021", the display position is greater than "1023" '(right end) This

  impossibility is corrected by steps 110 and 116.

  When the movement speed is not zero, the CPU 58 determines whether or not the present pointer position is less than "1023" (right end in step 112) If the

  present position is not the right end of the display

  chage, a step 118 is followed in order to move the pointer by one step to the right and, thus, to decrease the speed of movement of the pointer When the present position of the pointer is the end

  right, the pointer position is not moved and the

  ment returns directly to the flowchart of FIG. 2 In step 120, the CPU 58 transfers the address, storing a predetermined signal such as "1", in the circuit 52 for memorizing

  pointer by moving it from the present position to the posi-

  tion fixed by step 114, 116 or 118 In other words, "1" is transferred to an address which is the address present plus three (step 114), to the address "1023" (step 116), or to an address which is the address present plus 1 (step 118) After step 120,

13 -

  the flowchart of figure 2 is followed.

  FIG. 3 C is the flowchart corresponding to the case where the right key is not pressed in the pointer mode In a step 122, the CPU 58 determines whether the left key of the keyboard 56 is pressed or not This step prevents processing wrong in

  the case where the two keys have been put in the not pressed state-

  during the processing of steps 86 to 106, and the processing returns to the flowchart of FIG. 2 if the left key is not pressed. Steps 124 to 136 correspond respectively to steps 108 to 120 of FIG. 3 B The differences are that (1)

  parameters for determining the present position are respective-

  ment '2 "and" O "' in steps 126 and 128, (2) the direction of movement-

  ment of steps 130 and 134 is the left direction, and (3) the displacement position of step 132 is "O" for the displacement of the position of the pointer to the left in FIG. 3 C. The flow charts of FIGS. 3 D 1 and 3 D 2 are followed when it is determined, in step 96, that the present mode is not the pointer mode In this case, the displacement of the display position is defined by the modification of the time delay in scan B In a step 138, the CPU 58 determines whether the mode

  delay, namely the scanning mode B, or an intensity modulation mode

  sity (the intensity of the display in scan A is modified by scan B) is chosen, and a step 140 is followed if the mode

  delay has been chosen If the delay mode has not been chosen, that is

  say if scan mode A has been chosen, processing returns

  in the flow diagram of FIG. 2 In step 140, the CPU 58 deter-

  mine if the present value of the speed of movement is "50", and performs a connection to a step 146 if the speed is "50" When the speed of movement is not "50", a step i 42 is chosen and the CPU 58 determines whether or not the present mode is scan mode B step 146 is followed via a step i 44 if scan mode B has been chosen, or else step 146 is carried out

  directly if this is not the case - Steps 140 and 142 cor-

  correspond respectively to steps 98 and 100 of FIG. 3 B. o, in step 140, the UCI 58 determines whether or not the present value of displacement is the first displacement, and step 142

  only leads to step 144 when the display is amplified.

  In step 144, V'UCT 58 calculates the difference between the scanning speed A and the scanning speed B, and fixes the speed of movement as a function of the difference which is defined as being the amplification rate Thus, V 'UCT 58 operates, for step 144, as a processor making it possible to obtain the amplification rate of the amplification means In step 144, V'UCT 58 can produce, instead of the difference, the ratio of the scanning speed A at the scanning speed B In step 146, the CPU 58 determines whether the right key of the keyboard 56 is pressed or not A step 148 of FIG. 3 D 2 is followed (mark X) if the right button is pressed, and the flowcharts in Figures 3 E 1

  and 3 E 2 are followed if this is not the case (reference E).

  In FIG. 3 D 2, step 148 leads to a step 150 if the scanning mode B is chosen or leads to a step 152 if

  this is not the case, i.e. if the intensity modulation mode

  sity has been chosen In step 150, V'UCT 58 determines whether the displacement value is zero or not When the value of

  displacement is zero, i.e. when the position of affi-

  chage has not yet been moved, step 156 is followed.

  When the display position has already been moved, a step 154 is followed. Step 154 leads to step 156 when the movement speed is greater than or equal to "16" (greater than or equal to the movement speed "6 "), or else step 154 leads to step 158 when the speed is greater than the speed of movement" 6 "In step 156, when the present position is less than" 1023 "(the right end) , step 160 is

  followed to move the display position one step to the right.

  Since this is the case where the movement speed is slow,

  a displacement value corresponds to a step When it is determined

  mined in step 156 the display position is "1023", ie the right end, a-step 172 is followed If the speed of movement is high, V'UCT 58 determines the display position present in the step 158 A step 164 is followed if the display position is less than "1021", or a step 166 is

  followed if the display position is greater than or equal to "1021".

  The CPU 58 moves the display position three steps to the right in step 164, and it moves the display position

  directly at "1023", that is to say at the far right, in.

  step 166 In the intensity modulation mode, step 152 leads to step 168 when the present position is less than "1019", or leads to step 170 when the position

  present is greater than or equal to "1019" Since the modu-

  intensity does not enhance the display, the moving speed is high The display position is moved by

  5 steps to the right in step 168, and it is moved to the end

  right side in step 170 In steps 168 and 170, the display displacement is defined as displacement of the intensity modulation part to be amplified, In a step 162, the CPU 58 moves the display position by depending on the point set in step 160, 164, 166, 168 or 170 The movement of the display position corresponds to

  a modification of the delay time of display B, as below

  above described UCT 58 applies a numerical value to the conversion

  weaver NA 22 via the omnibus line 16 to fix the display position The display is moved one step, three steps or five steps by adding the steps fixed to the numerical value of the present position The comparator 24 compare the

  main scanning signal from scanning circuit A-

  with the analog value coming from the converter NA 22, so that the scanning circuit 26 begins to produce the scanning signal after the set delay time has elapsed In a step 172, V'UCT 58 commands the indicator 54 d '' display time

  newly attached, and it returns to the flowchart in Figure 2.

  Figures 3 E 1 and 3 E 2 represent the flowcharts corresponding to the case where the right key is not pressed in the delay mode. In a step 174, the UCU 58 determines whether the left key is pressed or not. A step 176 is followed if this is the case, or else the flowchart in FIG. 2 if this is not the case Steps 176 to 200 correspond respectively to steps 148 to 172 of FIG. 3 D 2, and the only differences are that the direction of movement is different and the parameters for determining the present position are different due to

  of the difference in the directions of movement.

  Figure 4 is a block diagram of part

  of another embodiment according to the invention This embodiment

  sation controls the display position (delay time) as a function of the amplification rate of the scanning mode B The scanning speeds of scanning circuit 20 and scanning circuit 26 are controlled respectively by a scan speed switch A 202 and scan speed switch B 204 Switches 202 and 204 are digital switches The digital output signals from switches 202 and 204 are applied to a digital divider circuit 206 that acts as a processor for the calculation digital of the ratio of the scanning speed A to the scanning speed B The digital divider circuit 206 can be V'UCT The digital output signal

  from the divider circuit 206 is loaded, as a divider ratio

  frequency sion, in a counter 208 (by an input -td) which counts a clock signal reaching it, by its input h A of a generator 210 of clock signals up to the value fixed by the divider circuit 206 to produce an output signal (carry-over and overflow signal), then count the clock signal again These operations are repeated The output signal from counter 208 is applied to a counting terminal cpt or a

  countdown terminal dept of a counter 216 via-

  respectively a right button 212 or a left button 214 -

  When the right key 212 is pressed, the counter 216 counts the output signal coming from the counter 208 in order to increase the counting value Conversely, when the left key -214 is pressed, the counter 216 counts the output signal from the counter 208 in order to decrease the count value The content of the counter 216 is transformed into an analog signal by the converter NA 22, and the analog signal is compared with the scanning signal coming from the scanning circuit A by the comparator 24 (FIG. 1 ) in order to control the delay time of the scanning circuit 26 B. Since this embodiment controls the frequency of the signal to be applied to the counter 216 as a function of the ratio of the scanning speed A to the scanning speed B, the time of delay var Ie,

  that is, the speed of movement from the home position

  chage is kept substantially constant compared to TRC-32,

  regardless of the display amplification ratio The comp-

  ters 208 and 216 can respectively be integrated circuits

  of type "1650" and "74 L 5192" Circuit 206 can produce the diff-

  reference between the two digital input signals.

  FIG. 5 shows a block diagram of part of a third embodiment according to the invention This embodiment comprises a counter 218 and a multiplexer 220 in place of the counter 208 of FIG. 4 The counter 218 counts the clock signal coming from the generator 210 of clock signals and produces 8-bit digital signals QO to Q 7 for example The multiplexer 220 chooses one of the output signals QO to Q 7 of the counter 218 under control of the signal output from the divider circuit (or a subtraction circuit) 206, and the selected output signal is applied via the keys 212 and 214 to the counting and counting down counting terminals of the counter 216 When the multiplexer 220 chooses the bit higher order, it takes a long time for the counter 216 to modify the output signal When the multiplexer 220 chooses the lower order bit, it takes a

  short time for counter 216 to modify the output signal.

  Thus, this embodiment has the same advantage as the mode

Figure 4.

  Figure 6 is a block diagram of part of a fourth embodiment according to the invention In this embodiment, there are restrictively two types of speeds

  displacement for example A counter 222 divides by N the frequency

  quence of the clock signal coming from the generator 210 of clock signals, and produces the output signal A counter 224 divides by M (M) N) the frequency of the clock signal and produces the signal

  output A switch 226 is associated with the amplification of

  chage, and selects counter 222 or counter 224, respectively

* only for a normal state or for an amplified display state.

  For the rest, the operation is the same as that of the fi-

  gure 4, and no description is given.

  As indicated above, the invention can displace

  the display position of the waveform or the visual pointer

  ses with a substantially constant speed relative to the display means independently of the amplification of the displayed waveform, since the speed of movement of the display position is adjusted relative to the waveform of the pure signal in depending on the amplification rate, for example the difference

  between the non-amplified display and the amplified display or the

  port of the non-amplified display to the amplified display, for the amplitude or the time axis of the displayed waveform Thus, it is easy to adjust the display position of the display device waveforms when the waveform displayed

is magnified.

  Of course, those skilled in the art will be able to ima-

  gin, from the processes and devices whose description

  has just been given by way of illustration and in no way limiting, various variants and modifications not departing from the scope of the invention For example, the direct current levels coming from the converter NA 22 of FIGS. 1, 4, 5 and 6 can be applied as offset voltage to the vertical amplifier 38

  or to the horizontal amplifier 30 of FIG. 1 A multiplica-

  Analog tor can be used as a processor instead of the CPU, and a voltage controlled oscillator can be used to modify the clock frequency according to the output signal of the processor The display means can be a device liquid crystal or plasma type flat display instead

of the TRC.

-1 2536863

Claims (14)

  1 waveform estimation device, characterized in that it comprises: a display means (32) which displays the signal waveform; amplification means (26; 30) which amplifies the waveform of the displayed signal;   display position control means (22, 24)   a chage which controls the display position of the waveform of the signal displayed on said display means; and a processor (58; 206) which controls the speed of movement of the waveform display position of the   signal as a function of said amplification means.   2 Apparatus according to claim 1, characterized in that the processor maintains substantially constant the speed of movement relative to said display means, independently   amplification of the signal waveform.   3 Apparatus according to claim 1, characterized in that said processor controls the speed of movement of the display position relative to the waveform of the signal-as a function of the ratio of an unamplified display to an amplified display if although the speed of movement of the display position is kept substantially constant with respect to said display means, regardless of the amplification of the waveform of the signal 4 Apparatus according to claim 1, characterized in that the processor controls the speed of movement of the display position relative to the waveform of the signal as a function of the difference between an unamplified display and an amplified display so that the speed of movement of the display position is kept substantially constant with respect to said display means, independently of the amplification of the waveform of the signal * Apparatus according to claim 1, characterized in   that said amplification means is a gain amplifier riable (30). 2536863   6 Apparatus according to claim 1, characterized in that said amplifying means is a delayed scanning circuit (26) which produces a delayed scanning signal, which is delayed by   compared to a main scan signal.   7 Apparatus according to claim 6, characterized in that   that said display position control means is a comparison   sensor (24) which compares the main scanning signal with a level   direct current to trigger said delayed scanning circuit.   8 Apparatus according to claim 7, characterized in that the processor controls the speed of variation of the DC level as a function of the amplification of the waveform of the signal.   9 Waveform display device, characterized in that it includes -   display means (32) which displays the waveform of a signal; amplifying means (30) which amplifies the waveform of the signal displayed on said display means; pointer storage means (46, 52) for superimposing a pointer on the waveform of the signal displayed on said display means; pointer position control means (52) which controls the pointer display position; and a processor (58) which controls the speed of movement of the pointer display position in accordance said amplification means.   Apparatus according to claim 9, characterized in that the processor maintains the speed of movement substantially constant with respect to said display means, independently of   amplification of the signal waveform.   11 Apparatus according to claim 9, characterized in that the processor controls the speed of movement of the display position relative to the waveform of the signal according to the ratio of an unamplified display to an amplified display so well that the speed of movement of the display position is maintained   substantially constant with respect to said display means, independent   especially the amplification of the signal waveform.   12 Apparatus according to claim 9, characterized in that the processor controls the speed of movement of the display position relative to the waveform of the signal as a function of the difference between an unamplified display and an amplified display so well that the speed of movement of the display position is kept substantially constant with respect to said display means, regardless of the amplification of the shape signal wave.   13 Apparatus according to claim 9, characterized in that said amplification means is an amplifier (30) with variable gain. 14 Apparatus according to claim 9, characterized in that said pointer storage means modifies the intensity of the waveform of the signal displayed on said display means to view the pointer.   Method for viewing waveforms, characterized in that it comprises the following operations: viewing the waveform of a signal on a display means; amplifying the displayed waveform of the signal; and move the display position of the waveform of the signal with a substantially constant speed relative said display means.   16 Method according to claim 15, characterized in that it further comprises the operation consisting in producing the ratio of an unamplified display to an amplified display for tracking the display position with the speed substantially constant by report to said display means.   17 Method according to claim 15, characterized in that   that it further includes the operation of producing the diff-   ference of a non-amplified display and an amplified display to move the display position with speed substantially   constant with respect to said display means.   18 Method for viewing waveforms, characterized in that it comprises the following operations: viewing the waveform of a signal on a display means; amplifying the displayed waveform of the signal; superimpose a pointer on the displayed waveform of the signal; and move the pointer display position with a   speed substantially constant with respect to said display means.   19 The method of claim 18, characterized in that it further comprises the operation of producing the ratio of an unamplified display to an amplified display to move the display position with the speed substantially constant   with respect to said display means.   The method of claim 18, characterized in that it further comprises the step of producing the difference between an unamplified display and an amplified display for moving the display position with speed substantially   constant with respect to said display means.