DE1947862C3 - Device for the digital transmission of analog data of a function with sampling of the function along a sequence of predetermined values of the independent variables - Google Patents

Description

The invention relates to a device for digital transmission, in particular storage of analog data of a function, in particular a one-dimensional function y = / (. V), in which a feeler element of a measuring device determines the independent variable (λ) l of a scale with preferably equally large increments Δλ- sampled and transmission channels, in particular memories for digital transmission of the function values j> ₀ , y _u J ₂ · " ) 'nv)' n belonging to the sampled x-values, are provided.

State of the art

In the known devices of the type described, there is the disadvantage that the number of tactile steps no reliable measure of the independent variance

trained maximum memory (VZ), which represents the 35 loaned, if during the scanning of the sequence of up-down counters (VRZ) by a λ> values uncontrolled backward and repeat step leads and a comparison stage (d) for forward steps, im The following errors also exist, the counter readings of VRZ and VZ , which just mentioned, occur. If these counter readings are the same, the gate circuit occurs, for example, when the independent variable represents a (J) for the passage of the grain distance from the probe (T _x ) , in particular during scanning

at low speeds due to the fact that the runner of the scanning device does not travel the distance continuously, but by jerking,? .. _u . at the transition from static to sliding friction, moves back one or more tactile steps and then traverses this section forwards again.

ending step pulses (St,) releases (Fig. 5).

3. Apparatus according to claim 1, characterized in that the device for generating the decrease signal consists of a zero value discriminator (k) which is connected to the output of the up-counter (VRZ) , and that the up-down counter (VRZ) Via an AND stage (g) step signals only from backward steps (Sr) and repeat forward steps (S ₁₀ ) . Such areas of the function y = f {x) are then scanned three times, namely in a first forward, in a reverse and a second forerun. In the

are supplied by the first input of the 50 determination of the x-values from the number of the memory AND stage (g) with the feeler element (T _x ) for the values then wrong results are obtained.

In order to avoid such errors due to a temporary retraction of the feeler element, one can, as described in

G
known devices happens to each measured

Step pulses (S _v , S _n S _w ) connected while
the second input is at the output of an OR stage (A), the first input of which is via an inversion stage (j) with the feeler element (T _x ) and its function value y " also the value x _{n of} the independent second input via an inversion stage {/ ') digitize with the variable and the value pair .v ", y"

is transmitted or saved for further processing the number of measuring points is large, as is the case in the evaluation of photographic mass spectrograms

Output of the zero value discriminator (k) is connected (Fig. 6).

4. Device according to one of claims 1
to 3, characterized in that the output ⁶ ° is the case, this also results in a correspondingly large one

gg

of the discriminator (D) for first forward steps [Sv) is connected to the control input of an analog-digital converter (ADC) for the associated function values (y) (FIG. 2).

5. Device according to one of claims 1 to 3, characterized in that the output of the discriminator (D) for first forward steps (Su) with the first input of an AND stage (a) data volume and a large amount of means for digital transmission or Storage. In order to avoid this effort and at the same time to record the scanning distance as precisely as possible, one can, as is also known, use a forward / backward counter which suppresses the backward steps. In this way, the error directly caused by backward steps can be eliminated, but not the error.

which results from the repetitive forward steps following the backward steps (reference 1). In the case of incrementally operating digital position controls, it is also known to collect all position data to be entered in the counting memory according to size and direction as the distance from the setpoint r of the respective previous position. This measure can also avoid errors caused by repetitive forward steps, however, this method also has the disadvantage of undesirable in the case of a large number of nominal position values great effort (citation 2).

task

The invention is based on the object of creating a device of the type specified at the outset which, with a simple structure, avoids incorrect evaluations iei of digital transmission as a result of incorrect steps, namely both backward and repeat forward steps.

Solution of the task

This object has been achieved according to the invention in that one of the feeler element for the independent Variable controlled discriminator provided for first steps forward with up / down counter is, which is followed by a device for generating a decrease signal, which i; via a Gate circuit a passage for the step pulses coming from the feeler element for the independent variable locks as soon as the up / down counter is triggered by a decrease in the feeler element Backstep pulses experience a reset and the passage is only released after the up-down counter returned to its initial position before resetting by means of forward-stepping pulses and thus the decline signal disappears.

With such a device it is possible to take all the wrong steps in either the digital transmission suppress them or, in order to be able to take them into account in the later evaluation, to mark them specially.

The device for generating the decline signal can be based on the utilization of various criteria. To distinguish between first-time forward steps and false steps, for example, the at the upward and downward counting of the scanning steps, the maximum count reached in each case is saved and the increase or non-increase of the maximum counter reading as a criterion for each key step can be used to determine whether there is a first forward step or a miss. One can set up to generate the downward signal also in such a way that downward steps are counted separately that the difference between backward steps and repeat forward steps is formed and that at each forward step the zero or non-zero difference is used as a criterion for this whether it is a first-time forward step or a repeat forward step.

60 Description of exemplary embodiments

An embodiment of the invention is shown in the drawing and will be described in more detail below described. F.s shows

Fig. 1 the diagram of a one-dimensional function y = / (A-),

2, 3 and 4 block diagrams of a device according to the invention for digital transmission or Storage of analog data of the function shown in Fig. 1, in three different embodiments, 5 and 6 show the discriminator of the circuit according to FIGS. 2, 3 or 4 in two different embodiments and

7 shows a pulse diagram to illustrate the mode of operation of the circuit according to FIGS. 5 and 6. The exemplary embodiments illustrate the use of the invention in the digital evaluation of photographic spectrograms, as they are supplied by a mass spectrometer in mass spectrometry. The mass spectrum is in the form of a line spectrum L in which mass lines M appear. The position of any mass line M _n is measured by the distance .v "of this mass line from a selected initial value .Y ₀ on a .v-scale Sk parallel to the x-direction of the photographic plate F : the degree of blackening of the relevant mass line M _n represents the function value To measure the values of χ and y , a photoelectric measuring device T designed as a sensing device is provided, under which the photographic plate F with the scale 5A- is moved in the direction of the arrow P.

For digital storage of the analog measured values of the one-dimensional function y - /(.v), a double probe T _x , T _{y of} the measuring device 7 ″, of which the first scans the .v scale Sk, the second scans the photo plate F with the mass spectrum , Corresponding values of .v and 3 'in a sequence of measured value pairs .Y ₀ , y ₀ ; .Y ₁ , .V ₁ ; .Y ₂ , y » "' ^a b · In the example shown, this scanning is carried out with constant increments Av the independent variable .v. To determine the steps, the .v-scale Sk is provided with graduation marks r , which, starting with the initial value .Y ₀ , follow one another at regular intervals corresponding to the increment Δ.ν. When the scale moves, these scale marks r move past the feeler element T _x and generate step signals in the feeler element which, in a manner to be described in more detail, are used to resolve a digital transmission in the form of digital storage of the function value associated with the relevant .v value, e.g. B. of the value. \ "Associated function value ν", are used in a digital memory Sp .

For the subsequent evaluation of the digital storage it is essential that one knows not only the instantaneous value of the analog function value y ", but also the associated value of the independent variable, the value .v _n , of each measuring point. For this purpose, as is done in known devices, for each measured function value y _n , the value .Y _{n could also be} digitized and the value pair .Y _n ,) ',, transferred or stored for further processing. If the number of measuring points is large, as is the case with the evaluation of photographic mass spectrograms, then there is also a correspondingly large amount of data and a large amount of resources for digital transmission or storage. In order to reduce this effort, in the exemplary embodiments shown _{, the function along the value sequence .Y 0} , .Y ₁ , Xn · ·· X _n ], xJi of the independent variable x is sampled in a manner known per se, and only the _{Function values v n} , ) \, .1 »" -.1 ¹ H], V _n belonging to the sampled .γ-values are stored in a sequence determined by the sampling, while the value .v "belonging to any stored function value y» of the independent variables χ by counting the

stored function values from a reference value of the independent variables, preferably acquired by digital storage or given by a known function value, e.g. B. from the initial value .V _{0 is} detected. This saves - with the exception of a single sampling point - the transmission or storage of the amount of data of the independent variables that is necessary to identify the position of all sampling points. If the .v values were run through by the scanning device in an undisturbed forward sequence, then one only needed to count the digital storage values run through in order to determine the position .v "of any storage value y _n . In particular at low scanning speeds, however, it happens that the measuring object, in the present example the photographic plate F, does not pass continuously in the same direction at the measuring point, the probe element T _x and Ty , but by jerking, e.g. B. at the transition from static to sliding friction, also goes back one or more increments of travel and then runs through this distance forwards again, as has already been explained above. As is known, the error caused thereby can be reduced by using a forwards-backwards indicator which suppresses the backward steps. In this way, the error caused directly by the backward steps Sr can be eliminated, but not the error which results from the repeat forward step c Sir following the backward steps Sr.

In order to rule out this error as well, such as B. is illustrated in Fig. 2, in the devices according to the invention, an additional distinction is made as to whether the forward steps are first-time forward steps S, · or repeat forward steps S, _r . For this purpose, a discriminator D controlled by the measuring device Γ, which distinguishes between first forward _{steps Sr on the one hand and downward switching S r} and repeat forward steps S »· on the other hand, is provided, which only emits signals for real, ie first-time forward steps S.

The r in the Taslgüed T _x of the scale lines derived signals S _r, S _r and S ₁ are the discriminator D via two channels V. S supplied. In the example shown, step signals S ₁ -, S _r and S "are generated in feeler T _x as the scale lines r advance. Of these step signals, only the forward messages pass through the first channel V , namely during the first forward steps and during the repetitive forward steps, while the second channel S carries signals of all steps, i.e. also the signals S _{r of} the backward steps. In the discriminator D _{, only first forward steps S r} corresponding signals are derived from these signal groups in a manner to be described below.

The signals ν derived in the feeler element T _y from the degree of blackening of the mass lines M are fed to an analog-to-digital converter ADC after amplification in an amplifier V _y .

In the exemplary embodiment shown in FIG. 2, the backward _{steps S r} and the repeat forward steps S, r are suppressed as false steps in the digital storage. For this purpose, the analog-to-digital converter ADW, as described in more detail below, is only driven by the signals S, obtained in the discriminator D from the first forward steps, so that the ADC only sends digital output values corresponding to the associated analog function values y to the digital memory during the first forward steps Sr Sp there.

In the exemplary embodiment shown in FIG. 3, steps in digital storage are also suppressed. For this purpose, the ADC is driven by all the step signals S ₁ -, S 1, S _n - from the second channel S or by the only forward steps S _r , S "- corresponding signals from the first channel V and the associated function values y are used as corresponding digital output values given to an AND stage α whose first input is connected to the output of the discriminator D and whose second input is connected to the output of the ADC , so that at the output of the AND stage α functional values are only available for storage when the first forward steps S - corresponding signals are available.

In the embodiment shown in FIG

Errors in digital storage are not suppressed, but are specially identified by an additional bit. For this purpose, the ADC of all step signals S,., S ,, S ". controlled and the associated function values y are given to the digital memory Sp by corresponding digital output values. In addition, error-step signals S ₁ , S ". given to the digital memory Sp in order to identify the digital values v, which correspond to errors, by an additional bit. The incorrect step pulses are obtained at the output of an AND stage Λ, the first input of which is connected to the output of the discriminator D via an inverting stage c and the second input of which is connected to the second channel S.

In FIGS. 5 and 6, two different embodiments for the discriminator D for deriving the signals S, ·, are shown. FIG. 5 shows an embodiment in which the discriminator D is provided with a maximum memory in the form of a precounter V7 . which always leads a forward-backward counter VRZ by one step and whose status is compared with the status of the VRZ in a comparison stage d which, if the status of the VRZ and the status of the VZ are equal, gives a gate pulse to an AND stage /, the second of which Input all step _{signals S 1} -, S _r , S " are fed from the feeler T _x via the second channel S, so that the desired, only first forward steps S, corresponding signals are available at the output.

6 shows an embodiment for the discriminator>, in which the difference S _r -S ", between backward steps S _r and subsequent forward steps S _{w is} measured and step signals are only output if this difference S _r -S ₁ , -equal Is zero and there is a step forward. For this purpose, an up / down counter VRZ is provided, to which, via an AND stage jr, the step signals S,., S _r , S ″. of channel S only those step signals are fed in for which the VRZ is either not set to zero or for which a reverse message from channel V is present. To achieve this, the second input is the AND stage,? connected to the output of an OR stage h , the first input of which via an inverting stage / with the first channel V and the second input via a

Inverse stage 1 is connected to a null value discriminator k located at the output of the VRZ .

The upper input of the I'RZ, which is initialized with the value O at the beginning of the process, receives from the

AND stage g the counting pulses, while its left input can switch this counter to counting up or counting down. This input is designed so that it counts down for the logic signal 1 and counts up for the logic signal 0.

The counting pulses for this counter can only be sent to the counting input if the left input of the AND stage g, i.e. the output of the OR stage h, is at logic 1. So that the output of the OR stage h accepts this logic 1, it is either necessary that the steps are backwards (signal V - 0, ie output of the inverter stage ι equal to 1) or that the up / down counter has a result other than 0 indicates and thus the output of the zero value discriminator indicates k = logical 0, ie the output of the inverter ι indicates logical 1. Since in the present circuit the up-down counter will only show the value 0 or negative results with its output, this ensures that the pulses reaching the counting input can only be repeat up or down steps.

A further AND stage m is connected to its first input at the output of the zero-value discriminator A. Its second input is supplied with all step signals SY, S _r , S _w from the channel S and its third input is supplied with the forward messages. At the output of the AND stage m , therefore, only forward step signals occur when the zero value discriminator k indicates zero. However, this is only the case if it is not a matter of step signals from repeat forward steps S _w . At the output of the discriminator D , as in the embodiment according to FIG. 5, only steps from first forward steps S _v occur.

If a return of the measuring device T on the photographic plate / is to be feared only by short distances, the maximum memory VZ or the counter VRZ can be limited to processing the last, ie least significant, counting positions, which considerably reduces the cost of implementation.

Various modifications are still possible within the scope of the invention; in particular is an application Useful wherever there is a return option when scanning an independent changing consists.

5 ADW BezUjjszeichenliste a Analog-to-digital converter b AND level C. AND level D. Reverse stage IO d Discriminator F. Comparison level f Photo plate G AND level A. AND level »5 OR level k Reverse stages L. Zero value discriminator M, M _n Line spar'.trum m Mass lines ao P. AND stage with three inputs S. Direction of arrow Sk first channel Sp scale Sv Digital storage first step forward and related Sr signal Su: Step backwards and the associated signal Repeat forward step T Mistakes 3 ° T _X , Ty photoelectric measuring device V Tactile elements V _x second channel Vy amplifier VZ amplifier 35 VRZ Advance counter V = / (Jf) Up / down counter V one-dimensional function .V Function value and associated signal *O independent mutable 40 * 0 «- ^V l» - ^V 2 Initial value of .v Δ.ν ··· AT _n -I, ^A 'n sample values of .v J'ui Vi, 3'2 Increments of χ ") 'n-ii Jn associated function value

For this purpose 3 sheets of drawings

«09 611/1

Claims (1)

Patent claims: J. Device for digital transmission, in particular storage of analog data of a function, in particular a one-dimensional function y = f (x), in which a probe element of a measuring device scans the independent variable (x) along a scale with preferably equally large increments Δλγ and transmission channels, In particular, memories are provided for the digital transmission of the function values y ₀ , J ₁ , y ₂ · "J'n-i, yn belonging to the scanned x values, characterized in that one controlled by the feeler element (T _x ) for the independent variable Discriminator (D) for first forward steps with up-down counter (VRZ) is provided, which is followed by a device for generating a downward signal (VZ, d in Fig. 5; k in Fig. 6), which is connected via a gate circuit (/ in Fig. 5; m in Fig. 6) blocks a passage (S - S _v ) for the step pulses (S _v , S _r , S _w ) coming from the feeler element (T _x ) for the independent variable (x) as soon as the Forwards-backwards k up counter (VRZ) is reset by backstep pulses (S _r ) triggered by a decrease in probe element 15 along (T _x ) and only enables passage after the up / down counter returns to its starting position with forward step pulses (S _w ) reaches before resetting and thus the decline signal disappears. 2. Device according to claim 1, characterized in that the device for generating the downward signal is connected as an up counter , the second input of which is connected to the output of an analog-to-digital converter [ADlV) for the associated function values (y) (Fig . 3). 6. Device according to one of claims I to 3, characterized in that the output of the discriminator (D) for first forward steps (St.) is connected via an inverting stage (i ·) to the first input of an AND stage (b) , whose second input on the feeler element (T _x ) for the step pulses (Sv, Sr, Sie) is present, while its output for identifying the incorrect steps (S _n S _u ) is connected to a memory (Sp) for the function values (y) (Fig . 4).