CA1098594A - Transversal filter - Google Patents
Transversal filterInfo
- Publication number
- CA1098594A CA1098594A CA293,739A CA293739A CA1098594A CA 1098594 A CA1098594 A CA 1098594A CA 293739 A CA293739 A CA 293739A CA 1098594 A CA1098594 A CA 1098594A
- Authority
- CA
- Canada
- Prior art keywords
- filter
- signal
- shift
- reactive
- output
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000003990 capacitor Substances 0.000 claims abstract description 47
- 239000000758 substrate Substances 0.000 claims abstract description 7
- 239000000463 material Substances 0.000 claims abstract description 4
- 239000004065 semiconductor Substances 0.000 claims abstract description 4
- 230000003321 amplification Effects 0.000 claims description 9
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 9
- 230000004044 response Effects 0.000 claims description 7
- 238000001208 nuclear magnetic resonance pulse sequence Methods 0.000 abstract description 8
- 238000010586 diagram Methods 0.000 description 21
- 238000001444 catalytic combustion detection Methods 0.000 description 10
- 238000005070 sampling Methods 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000875 corresponding effect Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000009499 grossing Methods 0.000 description 2
- JCYZMTMYPZHVBF-UHFFFAOYSA-N Melarsoprol Chemical compound NC1=NC(N)=NC(NC=2C=CC(=CC=2)[As]2SC(CO)CS2)=N1 JCYZMTMYPZHVBF-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- OYFJQPXVCSSHAI-QFPUQLAESA-N enalapril maleate Chemical compound OC(=O)\C=C/C(O)=O.C([C@@H](C(=O)OCC)N[C@@H](C)C(=O)N1[C@@H](CCC1)C(O)=O)CC1=CC=CC=C1 OYFJQPXVCSSHAI-QFPUQLAESA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
- H01L29/76—Unipolar devices, e.g. field effect transistors
- H01L29/762—Charge transfer devices
- H01L29/765—Charge-coupled devices
- H01L29/768—Charge-coupled devices with field effect produced by an insulated gate
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H15/00—Transversal filters
- H03H15/02—Transversal filters using analogue shift registers
- H03H15/023—Transversal filters using analogue shift registers with parallel-input configuration
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Ceramic Engineering (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Networks Using Active Elements (AREA)
- Filters That Use Time-Delay Elements (AREA)
Abstract
Abstract of the Disclosure A transversal filter with a charge shift device is disclosed for realizing a given filter function. The charge shift device includes a sub-strate of doped semiconductor material having arranged on one surface thereof a series of shift elements, each shift element having a plurality of capacitor elements in correspondence to the number of shift pulse sequence lines employed with the charge shift device. A serial input is provided for the filter to which an input signal is connected. Capacitor elements connected to one of the shift pulse sequence lines have non-reactive amplifying output units connected thereto. At least one of the capacitor elements connected to at least one of the other shift pulse sequence lines has an additional non-reactive amplifying unit connected thereto All of the non-reactive amplify-ing units also connect with an output of the filter.
Description
S~4 The presen~ invention rela~es to a transversal filter comprisinga charge shift device, wherein, on one surface of a substrate consisting of doped semiconductor material there is arranged a series of capacitor elements, each consisting of at least one insulating layer capacitor. For the oper-ation of the filter, the outer electrodes of each capacitor element are connected to one of a number of (at least two) shift pulse sequences which are displaced in phase relative to one another. The filter has a serial in-put to which the signal to be filtered is applied. In the case of capacitor elements intended for a selected member of the shift pulse trains, non-reactive amplifying outputs are provided which are connected to a filter out-put from which the signal to be filtered can be obtained. The amplification factor of each of these amplifying outputs corresponds to an assigned value of the pulse response of the filter function provided by the filter.
Transversal filters of the type described above are known (IEEE
Journal of Solid-State Circuits, Vol. SC-8, No. 2, ~pril 1973, pages 138 to 146 and Bell-Northern Research 11.4, pages 240 to 243). The charge shift devices consist of CCDs. l`he non-reactive~ amplifying outputs can be achieved either by means of the so-called split-electrode method or by means of true amplifiers having high-ohmic input impedances. In the case of the split-electrode method, each relevant capacitor element consists of two insu-lating layer capacitors which are arranged next to one another and are coupled by means of a doped zone in the substrate. The capacitance ratio of these two insulating layer capacitors is selected in dependence upon the desired amplification factor. The non-reactive, amplifying outputs are pro-vided only in the case of specific capacitor elements, and in fact only in those intended for one and the same predetermined shift pulse sequence. All the other non-reactive, amplifying outputs are connected to a filter output from which the filtered signal can be obtained. The amplification factor of each non-reactive amplifying output corresponds to an assigned value of the pulse response of the filter function which is to be provided by the filter.
An object of the present invention is to provide a transversal filter of the type described above which is able to provide different r~
. ~ , . .
~85~
additional filter properties as compared to a corresponding transversal filter of the conventional type which provides the same filter function.
The object is realized in that for at least one of the other capacitor elements there is provided at least one non-reactive, amplifying output which is connected to a filter output. Preferably the amplification factor of this output likewise corresponds to an assigned value of the pulse response of the filter function.
The fundamental advantages of the invention are as follows.
With a predetermined, arbitrary filter function, in comparison to correspond-ing transversal filters of conventional type, it is possible to considerablyreduce the surface space requirement and also, if the same surface space is retained, it is possible to considerably increase the reproduction accuracy of the filter function by means of additional, non-reactive, amplifying out-puts. Furthermore, different filter properties can additionally be ~lchieved simply ky modifying the shift pulse train frequencies during operation.
According to a broad aspect of the invention there is provided a transversal filter with a charge coupled device ~CCD) for realizing a filter function, comprising: a substrate comprised of doped semiconductor material having arranged on one surface thereof a series of capacitors each comprising a surface electrode and the substrate below each surface electrode as a counter electrode, each surface electrode being spaced from said surface by an insulating layer, at least three shift pulse lines supplying shift pulses displaced in phase relative to one another, said at least three shift ~ls~ I; ~ s e being respectively connected to at least first, second, and third groups of surface electrodes, a serial input means at one end of the CCD for connection to a signal to be filtered, the surface electrodes from the first group each having a non-reactive amplifylng output means connected thereto, the amplifying OlltpUt means also connecting to a filter output from which a filtered signal can be obtained, an almplification factor of each of said amplifying outputs corresponding to an assigned value of a pulse response of the filter f~mction to be realized by the filter, and at least one of the surface electrodes from the second group and at least one of the surface . :
,~
electrodes from the third group each having an additional non-reactive amplifying output means provided therefor which is connected to the filter output.
Figure 1 schematically illustrates a conventional transversal filter I in comparison to two exemplary embodiments II and III of the invention, which have likewise been shown schematically;
Figure 2 illustrates in diagram IV shift pulse trains plotted over time t, and beneath in a diagram V, ~he time curve of an arbitrarily selected signal which is to be filtered;
Figures 3 to 7 each illustrate a matrix-like plan, and Figure 8 shows, in two diagrams-VI and VII, the output signals of a conventional transversal filter in comparison to the output signal of an exemplary embodiment of the invention, plotted over time t.
In Figure 1, the conventional transversal filter is referenced 1. The charge shift device illustrated at: 10 consists of a CCD for two-phase operation. This means that each element of this CCD consists of two adjacent capacitor elements. These shift elements are individually provided with the reference numerals 1 to 4. The capacitor elements themselves are individually provided with the references 11, 12, 21, 22, 31, 32, 41 and 42. The capaci-tor elements 11, 21, 31 and 41 are intended for the one, and the other capacitor elemeDts for the other of the two shift pulse sequences 01 and 02 which are displaced in phase relative to one another. The serial input of the CCD is symbolieally represented and referenced E. In the case of each capacitor element which is intended for a shift pulse sequence, there is provided a non-reactive, amplifying output Kll, K21, K31 and K41. All the outputs are connected to a filter output A. In Figure 1, I, the outputs are provided in the capacitor elements 11, 21, 31 and 41. In place of these capacitor elements, such outputs could equally well be provided in the capacito~r elements 12, 22, 32 and 42. The symbols Kll, K21, K31 and K41 are to simultaneously represent the amplification factors of the relevant, non-reactive, amplifying outputs. The CCD 10 can generally be a CCD for n phase operation, where n = 2, 3, 4, 5 ----Each element of the CCD then contains n , adjacent capacitor elements, and n shift pulse sequences displaced in phase relative to one another must therefore be connected for operation.
In the exemplary embodiments II and III in Figure 1, in each capacitor element of the charge shift device there is provided a non-reactive, amplifying output, each of which is connected to a common filter output A.
In the two exemplary embodiments, the same non-reactive, amplifying outputs Kll, K21, K31 and K41 as in I have been employed. In the case of filter II, as with I, only these outputs are employed. If II is compared with I, it , will be seen that in II only four capacitor elements 11, 12, 21, and 22 are required. Everything else remains the same. Thus with II a surface space -3a-, , .
. . . .
5~
reduction of approximately 50% is achieved in comparison to I. When a CCD
for n phase operation (n = 2, 3, 4, 5 ...) is used, the surface space require-ments of II can be reduced by the factor l/n in comparison to I.
The filter III differs from the filter I in that in the case of the capacitor elements 12, 22, 32 and 42, additional non-reactive amplifying outputs K12, K22, K32 and K42, are provided which are connected to the filter output A. Thus with III, double the number of non-reactive, amplifying out-puts are provided as with filter I. When a charge shift device for n phase operation (n = 2, 3, 4, 5 ...) is used, up to n times as many outputs can be provided in a filter III as in a filter I.
The method in which the pulse train frequency of the shift pulse train for the charge shift device in filters II and III is selected is of fundamental significance. Two situations are of particular significance: on the one hand the pulse train frequèncy is selected to compare with the pulse train frequency fO for the fil-ter I, resulting in a doubling of the output frequency with which the filtered signal incoming at the filter output A is emitted (when a charge shift device for n phase operation is used it can be increased n times), or else the pulse train frequency of the shift pulse train is selected to be equal to foi2 (generally fO/n), whereby the output frequenc~
with which the filtered signal arrives at the ou-tput A is equal to fO. The output frequency at the output A is in any case double (generally n times) the sampling frequency with which the signal to be filtered is sampled at the input E.
Thus a tot~l of four such cases can be differentiated for the filters II and III in Figure 1. If the pulse -train frequency of the shift pulse train for the filter 1 in Figure 1 is referenced as above fO, that for filter II is referenced fII, and that for filter III is referenced fIII, these situations can be differentiated as follows: fII = fo' fIII = fo' fII = fo/n and fIII =
fo/n. In the specia] case of the exemplary embodiments, n = 2. The shift pulse train is to be understood as the pulse train with which an information . .
charge is forwarded from element to element of the charge shift device.
Figure 2, which shows two diagrams IV and V, provides further explanation. In diagram IV, over the time t the pulse train sequence of the shift pulse train for the charge shift device 10 is schematically represented by lines. The pulse train duration is referenced To~ Beneath, in diagram V, an arbitrarily selected form of a signal to be filtered is represented over the time t. The pulse train frequency of the shift pulse train is governed by f0 - l/To. The signal to be filtered is sampled in filter I with the pulse train frequency fO. The sampled signal values are referenced Sll, S21, S
and Slll. If the filter I were operated with the pulse train frequency 2fo~
additional signal values would be sampled. These additional signal values are likewise entered in Figure 2 and referenced S12, S22, S32 and Sl~2. How-ever, -these additional signal values are of no significance in the following.
In the filter I, the capacitor elements are provided with two-digit references xy, where x indicates the serial number of the element of the charge shift device, counting towards -the input E, and y indicates the serial number of the capacitor element in an element again counting towards the input E
(in the charge shift device 10~ y assumes the values 1 and 2 although generally it assumes the values 1 to n). Correspondingly, in filter I, the non-reactive, amplifying outputs are referenced Kxy. Accordingly, for example, the output K21 is the output provided in the capacitor element 21.
; The signal values which have been evaluated with the amplification ; factors will now be generally represented in the form Kxy . s~lv. The signif-icance of xy has already been given. For suv, u signifies the serial index of the sampling times tl, t2 etc. (see Figure 2), and v is a number from 1 .
to n, and additional~y indicates sampling times between tu and tU~l when the filter I is operated with a pulse train frequency of n . f0. Only the situa-tion n _ 1 is of significance for the following.
Figures 3 to 7 each illustrate a matrix-like scheme of the evaluated signals Kxy . suv. In each diagram only the columns with v = 1 are of "'.
5~
significance. The columns with v = 2 could be omitted. In each diagram the evaluated signal values K . s which are relevant to the output signal have each been surrounded by a circle. Specific circles are connected to one another by lines. This indicates that the values K y . suv in these circles connected by lines must be added in order to form the output signal.
The diagram in Figure 3 relates to the filter I in Figure 1. It has been assumed that the signal value Sll input at the time tl has reached the capacitor element 11 in the charge shift device. The capacitor element 11 then contains the signal value S21, the capacitor element 31 the value S31, and the capacitor element 41 the signal value S41. These signal values are read out from the charge shift device in parallel and the sum of the 11 11' 21 21' K31-S31 and K41-S41 is obtained at the filter output A. In the diagram, each of these evaluated signal values is surrounded by a circle and these circles are connected to one another by lines which indicate that these evaluated signal values must be added for the signal formation.
With the next pulse train, all these signal values are shifted towards the left by one capacitor element, whereby the capacitor element 11 now contains the signal value S21, and the capacitor element 41 contains a newly added signal value S51. ~aturally the charge shift device must be provided with an output stage following the capacitor element in order that each signal value contained therein can be read out with the next pulse train. This also applies to the exemplary embodiments II and III of the invention. A suitable output stage is, for example, an electrode having an implanted barrier. The signal values S2l9 S31, S41 and 551 are again read out in parallel and the 11 21~ K21.s31, K31.s41 and Kl~l.s5l is available at the filter output -A. This sum is again shown in the diagram in Figure 3. By continuing the diagram along the same lines, all the signal values of the filtered signal ~ -can now be determined in a simple manner. In the dlagram in Figure 3, the first three signal values of the filtered signal are referenced Al, A2 and A3.
The output frequency fA with which the filtered signal is withdrawn is . .
: . . , : . . : . :
governed by fA = fo The diagram in Figure li relates to the filter II in the case where fII = fo. If the signal value Sll input at the input E at the time tl has been forwarded to the capacitor element 11, the capacitor element 31 contains the signal value S21. Both signal values are read out in parallel and the value Al = Kll.sll + K31.s21 of the filtered signal is available at the filter output A. These signal values are shifted towards the left by one capacitor element following half the pulse train time, whereby the capacitor element 12 contains the signal value S21 and the capacitor element 22 contains a newly input signal value S31. Both signal values are read out at this time and the value A2 = K21.s21+K~l.s31 of the filtered signal is obtained at the filter output A. These two signal values are displaced towards the left by one capac-itor element for the full pulse train period, and at this time the value A3 =
Kll.s21+K31.s31 of the filtered signal etc. is obtained a-t the outpu-t A. Here the output frequency fA is governed by fA = 2fo~ whereas the sampling frequency fE~ wi-th which the signal to be filtered is sampled, is governed by fE = fo The diagram in Figure 5 likewise applies to the filter II, although ; now in the even-t in which fII = fo/2. If the signal value Sl1 input at the input E at the time t1 has been forwarded to the capacitor element 11, the capacitor element 31 now contains the value S31 since now sampling is carried out only following every second instant of time. At this time the value Al =
Kll.sll+K31.s31 of the filtered signal is obtained at the filter output A.
Following the time To = 1/fo, a shift by one capacitor element towards the left has occured, as a result of which the value A2 = K21.s31+K41.s51 is present at the output A a-t this time. ~ow the output frequency fA is fA =
fO, whereas the sampling frequency fE = fo/2 The diagram in Figure 6 relates to the filter III in the event that fIII = fo. The diagram illustrates the formation of the signal values of the output signal for the first three signal values A1, A2 and A3. The following signal values can easily be determined by continuing the diagram accordingly.
, Here fA = 2fo and fE = 0 The diagram in Figure 7 likewise applies to filter III, but in the case when fIII = fo/2- Again the formation of the first three signal values Al, A2 and A3 can be gathered from the diagram. By continuing the diagram accordingly it is easily possible to determine all the following signal values of the filtered signal. In this case fA = fo and fE = fo/2 In Figure 8, diagram VI illustrates an eYample of a filtered signal as is withdrawn from the filter output A of the filter I in Figure 1 during operation with the pulse train frequency f0. By way of comparison, diagram VII illustrates the output signal at the filter output A of the filter III in Figure 1 for the same input signal, this filter being operated with the pulse train frequency fIII = fo. It can clearly be seen tha-t a smoothing of the filtered signal is achieved with filter III in comparison to filter I. The information appears with double (n times) the frequency. This filtered signal per se no longer contains information as the output signal of the filter I, and is merely represented in a more favorab]e form, thus simplifying further processing. Thus, smoothing with an RC element can be sufficient -to enable the signal to be represented in the base band, i.e. to eliminate the higher frequency components contained in the sampling signal.
In the two exemplary embodiments, all the capacitor elements are pro~ided with non-reactive, parallel outputs. It should be noted that this is not required. In order to achieve new filter properties for the filter I, it is sufficient for at least one of the other capacitor elements to possess a non-reactive, amplifying output. In many embodiments, and likewise the described embodiments, the amplification factor of this output corresponds to an assigned value of the pulse response of the fil-ter function.
Although various minor modifications may be suggested by those versed in the art~ it should be understood that we wish to embody within the scope of the patent warranted hereon, all such embodiments as reasonably and properly come within the scope of our contribution to the art.
Transversal filters of the type described above are known (IEEE
Journal of Solid-State Circuits, Vol. SC-8, No. 2, ~pril 1973, pages 138 to 146 and Bell-Northern Research 11.4, pages 240 to 243). The charge shift devices consist of CCDs. l`he non-reactive~ amplifying outputs can be achieved either by means of the so-called split-electrode method or by means of true amplifiers having high-ohmic input impedances. In the case of the split-electrode method, each relevant capacitor element consists of two insu-lating layer capacitors which are arranged next to one another and are coupled by means of a doped zone in the substrate. The capacitance ratio of these two insulating layer capacitors is selected in dependence upon the desired amplification factor. The non-reactive, amplifying outputs are pro-vided only in the case of specific capacitor elements, and in fact only in those intended for one and the same predetermined shift pulse sequence. All the other non-reactive, amplifying outputs are connected to a filter output from which the filtered signal can be obtained. The amplification factor of each non-reactive amplifying output corresponds to an assigned value of the pulse response of the filter function which is to be provided by the filter.
An object of the present invention is to provide a transversal filter of the type described above which is able to provide different r~
. ~ , . .
~85~
additional filter properties as compared to a corresponding transversal filter of the conventional type which provides the same filter function.
The object is realized in that for at least one of the other capacitor elements there is provided at least one non-reactive, amplifying output which is connected to a filter output. Preferably the amplification factor of this output likewise corresponds to an assigned value of the pulse response of the filter function.
The fundamental advantages of the invention are as follows.
With a predetermined, arbitrary filter function, in comparison to correspond-ing transversal filters of conventional type, it is possible to considerablyreduce the surface space requirement and also, if the same surface space is retained, it is possible to considerably increase the reproduction accuracy of the filter function by means of additional, non-reactive, amplifying out-puts. Furthermore, different filter properties can additionally be ~lchieved simply ky modifying the shift pulse train frequencies during operation.
According to a broad aspect of the invention there is provided a transversal filter with a charge coupled device ~CCD) for realizing a filter function, comprising: a substrate comprised of doped semiconductor material having arranged on one surface thereof a series of capacitors each comprising a surface electrode and the substrate below each surface electrode as a counter electrode, each surface electrode being spaced from said surface by an insulating layer, at least three shift pulse lines supplying shift pulses displaced in phase relative to one another, said at least three shift ~ls~ I; ~ s e being respectively connected to at least first, second, and third groups of surface electrodes, a serial input means at one end of the CCD for connection to a signal to be filtered, the surface electrodes from the first group each having a non-reactive amplifylng output means connected thereto, the amplifying OlltpUt means also connecting to a filter output from which a filtered signal can be obtained, an almplification factor of each of said amplifying outputs corresponding to an assigned value of a pulse response of the filter f~mction to be realized by the filter, and at least one of the surface electrodes from the second group and at least one of the surface . :
,~
electrodes from the third group each having an additional non-reactive amplifying output means provided therefor which is connected to the filter output.
Figure 1 schematically illustrates a conventional transversal filter I in comparison to two exemplary embodiments II and III of the invention, which have likewise been shown schematically;
Figure 2 illustrates in diagram IV shift pulse trains plotted over time t, and beneath in a diagram V, ~he time curve of an arbitrarily selected signal which is to be filtered;
Figures 3 to 7 each illustrate a matrix-like plan, and Figure 8 shows, in two diagrams-VI and VII, the output signals of a conventional transversal filter in comparison to the output signal of an exemplary embodiment of the invention, plotted over time t.
In Figure 1, the conventional transversal filter is referenced 1. The charge shift device illustrated at: 10 consists of a CCD for two-phase operation. This means that each element of this CCD consists of two adjacent capacitor elements. These shift elements are individually provided with the reference numerals 1 to 4. The capacitor elements themselves are individually provided with the references 11, 12, 21, 22, 31, 32, 41 and 42. The capaci-tor elements 11, 21, 31 and 41 are intended for the one, and the other capacitor elemeDts for the other of the two shift pulse sequences 01 and 02 which are displaced in phase relative to one another. The serial input of the CCD is symbolieally represented and referenced E. In the case of each capacitor element which is intended for a shift pulse sequence, there is provided a non-reactive, amplifying output Kll, K21, K31 and K41. All the outputs are connected to a filter output A. In Figure 1, I, the outputs are provided in the capacitor elements 11, 21, 31 and 41. In place of these capacitor elements, such outputs could equally well be provided in the capacito~r elements 12, 22, 32 and 42. The symbols Kll, K21, K31 and K41 are to simultaneously represent the amplification factors of the relevant, non-reactive, amplifying outputs. The CCD 10 can generally be a CCD for n phase operation, where n = 2, 3, 4, 5 ----Each element of the CCD then contains n , adjacent capacitor elements, and n shift pulse sequences displaced in phase relative to one another must therefore be connected for operation.
In the exemplary embodiments II and III in Figure 1, in each capacitor element of the charge shift device there is provided a non-reactive, amplifying output, each of which is connected to a common filter output A.
In the two exemplary embodiments, the same non-reactive, amplifying outputs Kll, K21, K31 and K41 as in I have been employed. In the case of filter II, as with I, only these outputs are employed. If II is compared with I, it , will be seen that in II only four capacitor elements 11, 12, 21, and 22 are required. Everything else remains the same. Thus with II a surface space -3a-, , .
. . . .
5~
reduction of approximately 50% is achieved in comparison to I. When a CCD
for n phase operation (n = 2, 3, 4, 5 ...) is used, the surface space require-ments of II can be reduced by the factor l/n in comparison to I.
The filter III differs from the filter I in that in the case of the capacitor elements 12, 22, 32 and 42, additional non-reactive amplifying outputs K12, K22, K32 and K42, are provided which are connected to the filter output A. Thus with III, double the number of non-reactive, amplifying out-puts are provided as with filter I. When a charge shift device for n phase operation (n = 2, 3, 4, 5 ...) is used, up to n times as many outputs can be provided in a filter III as in a filter I.
The method in which the pulse train frequency of the shift pulse train for the charge shift device in filters II and III is selected is of fundamental significance. Two situations are of particular significance: on the one hand the pulse train frequèncy is selected to compare with the pulse train frequency fO for the fil-ter I, resulting in a doubling of the output frequency with which the filtered signal incoming at the filter output A is emitted (when a charge shift device for n phase operation is used it can be increased n times), or else the pulse train frequency of the shift pulse train is selected to be equal to foi2 (generally fO/n), whereby the output frequenc~
with which the filtered signal arrives at the ou-tput A is equal to fO. The output frequency at the output A is in any case double (generally n times) the sampling frequency with which the signal to be filtered is sampled at the input E.
Thus a tot~l of four such cases can be differentiated for the filters II and III in Figure 1. If the pulse -train frequency of the shift pulse train for the filter 1 in Figure 1 is referenced as above fO, that for filter II is referenced fII, and that for filter III is referenced fIII, these situations can be differentiated as follows: fII = fo' fIII = fo' fII = fo/n and fIII =
fo/n. In the specia] case of the exemplary embodiments, n = 2. The shift pulse train is to be understood as the pulse train with which an information . .
charge is forwarded from element to element of the charge shift device.
Figure 2, which shows two diagrams IV and V, provides further explanation. In diagram IV, over the time t the pulse train sequence of the shift pulse train for the charge shift device 10 is schematically represented by lines. The pulse train duration is referenced To~ Beneath, in diagram V, an arbitrarily selected form of a signal to be filtered is represented over the time t. The pulse train frequency of the shift pulse train is governed by f0 - l/To. The signal to be filtered is sampled in filter I with the pulse train frequency fO. The sampled signal values are referenced Sll, S21, S
and Slll. If the filter I were operated with the pulse train frequency 2fo~
additional signal values would be sampled. These additional signal values are likewise entered in Figure 2 and referenced S12, S22, S32 and Sl~2. How-ever, -these additional signal values are of no significance in the following.
In the filter I, the capacitor elements are provided with two-digit references xy, where x indicates the serial number of the element of the charge shift device, counting towards -the input E, and y indicates the serial number of the capacitor element in an element again counting towards the input E
(in the charge shift device 10~ y assumes the values 1 and 2 although generally it assumes the values 1 to n). Correspondingly, in filter I, the non-reactive, amplifying outputs are referenced Kxy. Accordingly, for example, the output K21 is the output provided in the capacitor element 21.
; The signal values which have been evaluated with the amplification ; factors will now be generally represented in the form Kxy . s~lv. The signif-icance of xy has already been given. For suv, u signifies the serial index of the sampling times tl, t2 etc. (see Figure 2), and v is a number from 1 .
to n, and additional~y indicates sampling times between tu and tU~l when the filter I is operated with a pulse train frequency of n . f0. Only the situa-tion n _ 1 is of significance for the following.
Figures 3 to 7 each illustrate a matrix-like scheme of the evaluated signals Kxy . suv. In each diagram only the columns with v = 1 are of "'.
5~
significance. The columns with v = 2 could be omitted. In each diagram the evaluated signal values K . s which are relevant to the output signal have each been surrounded by a circle. Specific circles are connected to one another by lines. This indicates that the values K y . suv in these circles connected by lines must be added in order to form the output signal.
The diagram in Figure 3 relates to the filter I in Figure 1. It has been assumed that the signal value Sll input at the time tl has reached the capacitor element 11 in the charge shift device. The capacitor element 11 then contains the signal value S21, the capacitor element 31 the value S31, and the capacitor element 41 the signal value S41. These signal values are read out from the charge shift device in parallel and the sum of the 11 11' 21 21' K31-S31 and K41-S41 is obtained at the filter output A. In the diagram, each of these evaluated signal values is surrounded by a circle and these circles are connected to one another by lines which indicate that these evaluated signal values must be added for the signal formation.
With the next pulse train, all these signal values are shifted towards the left by one capacitor element, whereby the capacitor element 11 now contains the signal value S21, and the capacitor element 41 contains a newly added signal value S51. ~aturally the charge shift device must be provided with an output stage following the capacitor element in order that each signal value contained therein can be read out with the next pulse train. This also applies to the exemplary embodiments II and III of the invention. A suitable output stage is, for example, an electrode having an implanted barrier. The signal values S2l9 S31, S41 and 551 are again read out in parallel and the 11 21~ K21.s31, K31.s41 and Kl~l.s5l is available at the filter output -A. This sum is again shown in the diagram in Figure 3. By continuing the diagram along the same lines, all the signal values of the filtered signal ~ -can now be determined in a simple manner. In the dlagram in Figure 3, the first three signal values of the filtered signal are referenced Al, A2 and A3.
The output frequency fA with which the filtered signal is withdrawn is . .
: . . , : . . : . :
governed by fA = fo The diagram in Figure li relates to the filter II in the case where fII = fo. If the signal value Sll input at the input E at the time tl has been forwarded to the capacitor element 11, the capacitor element 31 contains the signal value S21. Both signal values are read out in parallel and the value Al = Kll.sll + K31.s21 of the filtered signal is available at the filter output A. These signal values are shifted towards the left by one capacitor element following half the pulse train time, whereby the capacitor element 12 contains the signal value S21 and the capacitor element 22 contains a newly input signal value S31. Both signal values are read out at this time and the value A2 = K21.s21+K~l.s31 of the filtered signal is obtained at the filter output A. These two signal values are displaced towards the left by one capac-itor element for the full pulse train period, and at this time the value A3 =
Kll.s21+K31.s31 of the filtered signal etc. is obtained a-t the outpu-t A. Here the output frequency fA is governed by fA = 2fo~ whereas the sampling frequency fE~ wi-th which the signal to be filtered is sampled, is governed by fE = fo The diagram in Figure 5 likewise applies to the filter II, although ; now in the even-t in which fII = fo/2. If the signal value Sl1 input at the input E at the time t1 has been forwarded to the capacitor element 11, the capacitor element 31 now contains the value S31 since now sampling is carried out only following every second instant of time. At this time the value Al =
Kll.sll+K31.s31 of the filtered signal is obtained at the filter output A.
Following the time To = 1/fo, a shift by one capacitor element towards the left has occured, as a result of which the value A2 = K21.s31+K41.s51 is present at the output A a-t this time. ~ow the output frequency fA is fA =
fO, whereas the sampling frequency fE = fo/2 The diagram in Figure 6 relates to the filter III in the event that fIII = fo. The diagram illustrates the formation of the signal values of the output signal for the first three signal values A1, A2 and A3. The following signal values can easily be determined by continuing the diagram accordingly.
, Here fA = 2fo and fE = 0 The diagram in Figure 7 likewise applies to filter III, but in the case when fIII = fo/2- Again the formation of the first three signal values Al, A2 and A3 can be gathered from the diagram. By continuing the diagram accordingly it is easily possible to determine all the following signal values of the filtered signal. In this case fA = fo and fE = fo/2 In Figure 8, diagram VI illustrates an eYample of a filtered signal as is withdrawn from the filter output A of the filter I in Figure 1 during operation with the pulse train frequency f0. By way of comparison, diagram VII illustrates the output signal at the filter output A of the filter III in Figure 1 for the same input signal, this filter being operated with the pulse train frequency fIII = fo. It can clearly be seen tha-t a smoothing of the filtered signal is achieved with filter III in comparison to filter I. The information appears with double (n times) the frequency. This filtered signal per se no longer contains information as the output signal of the filter I, and is merely represented in a more favorab]e form, thus simplifying further processing. Thus, smoothing with an RC element can be sufficient -to enable the signal to be represented in the base band, i.e. to eliminate the higher frequency components contained in the sampling signal.
In the two exemplary embodiments, all the capacitor elements are pro~ided with non-reactive, parallel outputs. It should be noted that this is not required. In order to achieve new filter properties for the filter I, it is sufficient for at least one of the other capacitor elements to possess a non-reactive, amplifying output. In many embodiments, and likewise the described embodiments, the amplification factor of this output corresponds to an assigned value of the pulse response of the fil-ter function.
Although various minor modifications may be suggested by those versed in the art~ it should be understood that we wish to embody within the scope of the patent warranted hereon, all such embodiments as reasonably and properly come within the scope of our contribution to the art.
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A transversal filter with a charge coupled device (CCD) for realizing a filter function, comprising: a substrate comprised of doped semiconductor material having arranged on one surface thereof a series of capacitors each comprising a surface electrode and the substrate below each surface electrode as a counter electrode, each surface electrode being spaced from said surface by an insulating layer, at least three shift pulse lines supplying shift pulses displaced in phase relative to one another, said at least three shift pulse lines being respectively connected to at least first, second, and third groups of surface electrodes, a serial input means at one end of the CCD for connection to a signal to be filtered, the surface elec-trodes from the first group each having a non-reactive amplifying output means connected thereto, the amplifying output means also connecting to a filter output from which a filtered signal can be obtained, an amplification factor of each of said amplifying outputs corresponding to an assigned value of a pulse response of the filter function to be realized by the filter, and at least one of the surface electrodes from the second group and at least one of the surface electrodes from the third group each having an additional non-reactive amplifying output means provided therefor which is connected to the filter output.
2. A transversal filter as claimed in claim 1, characterized in that an amplification factor of said additional amplifying output means likewise corresponds to an assigned value of the pulse response of the filter function.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2658525.1 | 1976-12-23 | ||
| DE19762658525 DE2658525C2 (en) | 1976-12-23 | 1976-12-23 | Transversal filter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1098594A true CA1098594A (en) | 1981-03-31 |
Family
ID=5996474
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA293,739A Expired CA1098594A (en) | 1976-12-23 | 1977-12-22 | Transversal filter |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPH0249055B2 (en) |
| BE (1) | BE862285A (en) |
| CA (1) | CA1098594A (en) |
| DE (1) | DE2658525C2 (en) |
| FR (1) | FR2375766A1 (en) |
| GB (1) | GB1595985A (en) |
| IT (1) | IT1089198B (en) |
| NL (1) | NL7714198A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0004563B1 (en) * | 1978-03-31 | 1982-06-16 | Siemens Aktiengesellschaft | Transversal filter |
| DE2814053A1 (en) * | 1978-03-31 | 1979-10-11 | Siemens Ag | TRANSVERSAL FILTER WITH PARALLEL INPUTS |
-
1976
- 1976-12-23 DE DE19762658525 patent/DE2658525C2/en not_active Expired
-
1977
- 1977-12-12 FR FR7737366A patent/FR2375766A1/en active Granted
- 1977-12-21 NL NL7714198A patent/NL7714198A/en not_active Application Discontinuation
- 1977-12-22 IT IT3108577A patent/IT1089198B/en active
- 1977-12-22 CA CA293,739A patent/CA1098594A/en not_active Expired
- 1977-12-22 GB GB5362177A patent/GB1595985A/en not_active Expired
- 1977-12-23 JP JP15634377A patent/JPH0249055B2/en not_active Expired - Lifetime
- 1977-12-23 BE BE183813A patent/BE862285A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| FR2375766B1 (en) | 1980-08-22 |
| NL7714198A (en) | 1978-06-27 |
| DE2658525A1 (en) | 1978-06-29 |
| IT1089198B (en) | 1985-06-18 |
| GB1595985A (en) | 1981-08-19 |
| JPH0249055B2 (en) | 1990-10-29 |
| FR2375766A1 (en) | 1978-07-21 |
| BE862285A (en) | 1978-04-14 |
| DE2658525C2 (en) | 1986-02-27 |
| JPS5381045A (en) | 1978-07-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1098973A (en) | Transversal filter having at least one analog shift register, and a method for its operation | |
| CA1098594A (en) | Transversal filter | |
| US4609877A (en) | Buffer circuit with differential structure for measurement of capacitive charges | |
| JPS62214781A (en) | Signal recovery apparatus | |
| US4527261A (en) | Hiline interference eliminator | |
| US5686861A (en) | Filter circuit | |
| US4193050A (en) | Transversal filter | |
| US4745594A (en) | Offset-compensated switched-capacitor filter for TDM multichannel analog signals | |
| FI69382B (en) | KAMFILTERKOPPLING FOER SEPARERANDE AV EN FAERGVIDEOSIGNAL I SIA LUMINANS- OCH KROMINANSKOMPOSANTER | |
| US2907902A (en) | Low level signal commutator | |
| JPS6120172B2 (en) | ||
| US5306905A (en) | Method for minimizing 1/f and other low frequency noise in signal processing for focal plane array detector system | |
| US4385321A (en) | Correlated triple sampling circuit | |
| US4290034A (en) | Switched capacitor filter | |
| KR0132717B1 (en) | Semiconductor device | |
| US4366455A (en) | Switched-capacity amplifier, switched-capacity filter and charge-transfer filter comprising such an amplifier | |
| GB2235821A (en) | Integrated circuit and its connecting circuit | |
| US4126836A (en) | Balanced capacitance charge transfer device | |
| DE112017007185T5 (en) | Electronic module and power module | |
| JPH0758883B2 (en) | Type 2 filter circuit | |
| US4194172A (en) | Apparatus for filtering an electrical signal with a charge-coupled device | |
| US3517132A (en) | Gated amplifier circuit arrangement for time division multiplex switching system | |
| US4041328A (en) | Arrangement for the determination and visualization of measuring signals | |
| EP0330961B1 (en) | Telephone line interface circuit | |
| JPS59148413A (en) | Preamplifier |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |