Abstract: In a transversal filter equalizer, such as one using a tapped delay line, the present invention combines the symmetrically located pairs of tap signals, by means of adders and subtracters, to provide partial output signals which are separately controlled in amplitude and phase. These partial output signals, which have no d.c. components, are then summed with a partial signal derived from the center tap reference signal to reinsert the d.c. component and to provide the equalized output signal.

Abstract: A transversal filter has an analog shift register exhibiting a series input and a plurality of parallel outputs which are connected to a summing and/or subtracting circuit. A simple realization of signal weighting circuits assigned to the stages of the shift register is achieved in that n signal weighting devices assigned to a group of n stages are disposed in a signal path which extends from the input of the first stage of the group over all stages thereof and in that the signal weighting devices of the n stages respectively weight according to filter coefficients b.sub.1 -b.sub.n which occur in the system functionH(z)=b.sub.0 .multidot.(1+b.sub.1 .multidot.z(1+b.sub.2 .multidot.z(. . . (1+b.sub.n .multidot.z))))determining the filtered signal, where z represents the delay time per stage for each signal value. The transversal filter of the invention is useful in analog filters of communications technology.

Abstract: Update gain normalization is employed in adaptive filters to control weighting of the filter impulse response updates in order to converge properly to a desired impulse response. Singing, i.e., oscillating, of the filter is overcome by adjusting the update gain when an incoming signal power estimate used to normalize the gain exceeds a prescribed threshold value. In one example, the normalized gain is adjusted to be a fixed value for power estimate values which exceed the threshold. In accordance with another aspect of the invention, a single normalized gain value is used to adjust the update gain in two adaptive filters employed as echo cancelers in a bidirectional voice frequency repeater.

Abstract: Methods and apparatus for high speed signal sampling and recording utilizing mutual repulsion field-induced splitting of charge carriers in a charge transfer channel.

Abstract: A time domain filter having ideal high pass and low pass characteristics is provided by means of a one-shot monostable multivibrator and a flip-flop interconnected by means of an AND gate and an EXCLUSIVE-OR gate wherein the set time for the one-shot is equal to the half-period of the cut-off frequency. The time domain bandpass filter circuit having ideal bandpass filter characteristics comprises a pair of one-shot monostable multivibrators connected in cascade with each other and interconnected with a flip-flop by means of an AND gate. A further application of a modified time domain filter is that of time domain FM demodulator having an optional phase-locked loop.

Abstract: A digital peaking circuit for processing digital luminance signal in a video processing system combines parallel paths of delay elements and summing circuits to produce the desired luminance response curve with minimum hardware. Only one scaling circuit is required to achieve the desired frequency response characteristic and one multiplier is included to render the peaking circuit adaptive.

Abstract: In this transverse charge transfer filter having N MOS capacitors arranged on the same semiconductor substrate and provided with electrodes, the electrode of every other MOS capacitor has its ends covered by the ends of the electrodes of two adjacent MOS capacitors, the N MOS capacitors being arranged in n rows and the charge transfer direction in two adjacent rows being opposite, which makes it possible to compensate for the effects of the displacements of the masks used for manufacturing the transverse charge transfer filters.

Abstract: A digital filter imparting a desired tone color to the tone signal is realized by the combination of a digital pole filter and a digital zero filter capable of controlling a pole and a zero in an amplitude-frequency characteristic respectively. The amplitude-frequency characteristic of the digital filter is a composite of the respective characteristics of the pole filter and the zero filter. A "peak" portion and a "valley" portion in this composite characteristic can be set independently by the pole control of the pole filter and the zero control of the zero filter, whereby the desired tone color characteristic can be readily realized. Further, the digital filter may comprise a plurality of digital filters having respective different constructions and a connection switching circuit capable of setting arbitrarily connection between these filters. The filter characteristic as a whole can be diversely altered by changing the connection, whereby diverse tone color characteristics can be realized with ease.

Abstract: A transversal filter with an analog shift register has a plurality of parallel inputs and a serial output at which a filtered signal appears. An object is to provide as simple as possible a realization of the n signal evaluators allocated to the n stages of the shift register. This is achieved by providing the n signal evaluators in a signal path proceeding from the input of the first stage over all n stages, and to evaluate according to evaluation factors b.sub.n through b.sub.1 which occur in the system functionH(z)=b.sub.o .multidot.(1+b.sub.1 z(1+b.sub.2 .multidot.z( . . . 1+b.sub.n .multidot.z)))describing the filtered signal, where z is the delay which the signal values respectively experience when traversing a stage of the shift register. The filter is employed as an analog filter in communication technology.

Abstract: A charge-transfer-device (CTD) transversal filter which makes use of tap-weight-adjustment circuitry for removing effects of charge-transfer inefficiency (CTI) and fixed-pattern noise (FPN). The tap weights are adjusted by measuring the response of the CTD-transversal filter to an isolated pulse input and to a zero-frequency input. The results of the measurements and reference-filter coefficients are used by the tap-weight-adjustment circuitry in order to set tap weights for the CTD-transversal filter. The tap-weight-adjustment circuitry allows the frequency response of the CTD transversal filter to be accurately tailored even though the CTD filter suffers imperfections due to CTI and FPN.

Abstract: A transversal adaptive filter with a tap weight computer having a respective first and second input responsively coupled to a respective output and input of the filter, and including spectrum shaping means. The spectrum shaping means comprises matched or like preselected bandpass means interposed at the inputs of the tap weight computer.

Abstract: Input discrete samples x.sub.n are applied to an adder through a first set of feedforward paths which successively delay and multiply the samples by selected coefficient values and are also applied to an adder-subtractor through a second set of feedforward paths which successively delay and shift the input samples by selected values. Output discrete samples y.sub.n are supplied from the adder-subtractor to the adder through a first set of feedback paths by successively delaying and scaling the samples by selected values of coefficient and are also applied to the adder-subtractor through a second set of feedback paths by successively delaying and shifting the samples by selected values.

Abstract: Methods and apparatus for recording pulse signal information utilizing threshold integrating devices in which a pulse shaped signal is applied to a plurality of threshold integrating devices each having a predetermined quantity of electric charge carriers stored therein, in which the threshold integrating devices are responsive to application of electric potentials above a predetermined threshold potential value for altering the amount of charge stored in the charge storage zone of the threshold integrating devices. By providing a plurality of threshold integrating devices each having a different threshold potential, significant signal information may be obtained by passive application of the pulsed signal to a plurality of the devices. This signal information may be obtained by determining the amount of charge in the charge storage zones of the respective threshold integrating devices subsequent to application of the pulsed signal thereto.

Abstract: Disclosed is a programmable frequency converting filter having a plurality of selectable operating modes, and having frequency passbands of a unique width for each of the operating modes. The programmable frequency converting filter is comprised of a charge transfer device transversal filter, a non-sampling filter, and a frequency band selector. The transversal filter has an output lead coupled to an input of the non-sampling filter, and has clock leads coupled to the output of the frequency band selector. The frequency band selector has control leads for receiving logic signals which together select operating modes from the plurality of modes. The frequency band selector generates, on the clock leads, clocking signals having a unique frequency for each mode of the plurality.

Abstract: A method is described for generating continuously variable sets of weighting coefficients for application to weighting circuits of a sampled data filter. The generated coefficients are produced by scaling the time axis of the impulse response described by a set of standard or nominal weighting coefficients in an inverse manner to a desired scaling of the filter frequency response. The coefficient values at the scaled time points are calculated by a piecewise linear interpolation process and correspond to the scaled coefficients. By this technique, a large number of sets of weighting coefficients may be generated from a single set of coefficients with relatively few circuit elements.

Abstract: In a device for current-reading of a quantity of electric charges, the control circuit for the first and second MOS transistors receives a constant potential and comprises:a third transistor, the drain and gate of which are connected to the constant potential and the source of which is connected to the drain and to the gate of the second transistor;a second capacitor connected through one of its terminals to the nodal point of the second and the third transistor.The device is employed for reading quantities of charges which arrive under the storage electrodes of charge-transfer filters.

Abstract: A method and apparatus for eliminating narrow band noise and interference from a wide band signal while maintaining the wide band signal substantially intact.

Abstract: Loop gain normalization is employed in adaptive filters to control weighting of the filter characteristic updates in order to converge properly to a desired filter characteristic. Filter instability is avoided during intervals that transient or other rapidly pulsating signals are received or inputted by normalizing the update gain with a representation of a so-called fast attack estimate of a prescribed characteristic of the input signal. In one embodiment the fast attack estimate is the maximum of a plurality of power estimates generated from a corresponding plurality of subsets of amplitude samples of the received signal. In another embodiment, the maximum of the magnitude representations of the input signal samples is modified to represent the fast attack power estimate of the received signal.

Abstract: Loop gain normalization is employed in adaptive filters to control weighting of the filter characteristic updates in order to converge properly to a desired filter characteristic. Filter stability and rapid high quality convergence is realized for a variety of received or inputted signals by employing both long term and fast attack estimates of a prescribed input signal characteristic to normalize the update gain. In one embodiment, both long term and fast attack input signal power estimates are generated and one of the two estimate values is selected to normalize the update gain. Specifically, the fast attack estimate is modified by a predetermined value and, then, the larger of the long term estimate and modified fast attack estimate is selected to normalize the update gain.

Abstract: A basic coefficient to be used for calculation of a transfer function of a digital filter is read out from a ROM according to a cutoff frequency of a desired filter. The value of the coefficient read out from the ROM is gradually varied according to a desired resonance characteristic by an arithmetic circuit so as to reduce the memory capacity of the ROM for storing coefficients.

Abstract: A common channel charge transfer recursive filter has two delay lines, in which charges are transferred in opposite directions. Exchange bridges having two sections extend between the lines. Each section feeds a predetermined charge fraction to one of the two downstream electrodes with charges flowing from the two upstream electrodes. The charge transfer is controlled by a three-phase system (.phi.1, .phi.2, .phi.3). Split memory electrodes and the exchange bridges are connected to the first phase (.phi.1) bus. A transfer electrode is in each gap between an exchange bridge and a memory electrode and is connected to the second phase (.phi.2) bus. A second transfer electrode is connected to the third phase (.phi.3) bus. The gap between a memory electrode and the next exchange bridge is occupied by a transfer electrode connected to the second phase (.phi.2) bus and by a transfer electrode connected to the third phase (.phi.3) bus.

Abstract: CTD transversal filter, for time delayed forming of a given input signal being weighted and subsequently summed for producing a filter characteristic, with weighting coefficients optionally having a negative and a positive sign, including a separate input stage for forming each desired weighting coefficient for obtaining a desired filter characteristic, the input signal being scanned by a common scanning frequency for all input stages, being converted to a charge packet proportional to its voltage and being time delayed in the input stages, the input stages for forming the negative weighting coefficients being formed in an inverting manner as compared to the input stages for forming the positive weighting coefficients, gate electrodes of the input stages, the areas of the gate electrodes of the input stages under which the charge packets are formed proportional to the input voltage, corresponding to the ratio of the absolute values of the required weighting coefficients, and a common output stage in which the

Abstract: The effects of crosstalk of an FM carrier from a first signal channel into a second signal channel are reduced by a variable-frequency notch filter coupled in the second channel. The frequency of the notch in the transmission characteristic of the filter is controlled to track the frequency of the FM carrier. Signals in the second channel at the frequency of the FM carrier are attenuated, and therefore the crosstalk signal is attenuated and its effects reduced.

Abstract: A low cost automatic equalizer is provided for reducing the amplitude and phase distortion produced by close-in echos. The color subcarrier burst, or some other portion of the video signal having predetermined amplitude and phase characteristic prior to transmission, is gated into detection circuitry. A regenerated color subcarrier, phase shifted to be in phase with the subcarrier burst, is used to detect the in-phase and quadrature components of the subcarrier burst, which are indicative of amplitude and phase distortion. The signals indicative of amplitude and phase distortion are applied to a three tap delay line equalizer, where the amplitude and polarity of the first and third tapped signals are controlled in unison to reduce amplitude distortion, and where the amplitude of the first and third tapped signals is controlled in unison, but the polarity of the first and third tapped signals is controlled oppositely to reduce phase distortion.

Abstract: In order to make an adaptive filter, having a delay circuit, (3) taps of which include amplitude control circuits (43, 45, 47, 49, 51, 53, 55, 57) which are controlled by an error signal (output of 149), more suitable for use in television receivers, a number of said amplitude control circuits (45, 55) are controlled by both the error signal (output from 149, 151, 125 and 153 , 127 respectively) and an inverse version of a signal corrected by the filter (output 119, 121, 125 and 123, 127 respectively).

Abstract: The invention relates to an electrical filter circuit operated with a definite sampling and clock frequency f.sub.T, such filter being made up of CTD elements, and having at least one bipolar or quadripolar resonator in the form of a self-contained conductor loop (for example, C.sub.1, C.sub.2) with unidirectional transmission behavior.Differences in the transfer capacitances of such circuits are reduced, as far as possible, in order to thereby simplify integrated manufacture as far as possible, by positioning the frequency band to be filtered out at a frequency position which lies above half the clock frequency (f.sub.T /2), or in the range from f.sub.T /2 through 3f.sub.T /2.

Abstract: In the present invention, image processing is performed at speeds comparable to those achieved in parallel processing without requiring substantially more area on the substrate than that required in serial processing. In this invention, for an N.times.N processing kernel, N rows of image memory are processed in parallel through a plurality of N floating gate arrays of dimension N.times.N, N-1 of the data rows from the memory being recirculated through the N floating gate structures before being discarded. Each of the floating gate structures is offset from the adjacent floating gate structure by one row so that the data from memory need be recirculated only once.

Abstract: The dispersive effects of frequency selective fading in a digital, FM, or AM radio system are reduced by means of an adaptive equalizer (11) comprising a cascade of feed-forward stages (1,2, . . . N), each of which includes: a first parallel wavepath (1-1, 1-2, . . . 1-N) including a first adjustable attenuator (20-1, 20-2, . . . 20-N); a second parallel wavepath (2-1, 2-2, . . . 2-N) including a second adjustable attenuator (21-1, 21-2, . . . 21-N) and delay means (22-1, 22-2, . . . 22-N); and means (23-1, 23-2, . . . 23-N) for combining the signals in said wavepaths and for coupling said combined signal to the next stage. By a suitable selection of parameters, according to two unique relationships, a transfer function can be realized which can compensate for amplitude and delay distortions caused by minimum and nonminimum phase fades.

Abstract: A filter circuit comprising a charge transfer device of the type which includes first and second sets of charge storage devices, such as capacitors, the first and second sets of charge storage devices being supplied with first and second clock signals, respectively, and further including first and second sets of switches which are actuated in response to the first and second clock signals, respectively, each switch being operable, when actuated, to transfer charge between a charge storage device in one set and a charge storage device in the other set, thereby transferring a charge through succeeding switches to be temporarily stored in succeeding charge storage devices. A semiconductor element, such as a transistor, is actuated in response either to the first or to the second clock signals for transferring the charge stored in a first predetermined charge storage device to a second predetermined charge storage device.

Abstract: A time correction value for each digital switching signal is determined and a set of switching control signals is formed which produce a progressive switching of the digital signal as a function of the time correction value. Each time correction value is stored until the following digital switching signal. The method improves chroma keying in digital color television systems.

Abstract: A dynamically variable electronic delay line for real time ultrasonic imaging systems is disclosed which controllably phases the signals associated with an array of electromechanical transducer elements and thereby enables selective scanning and dynamic focusing of a target. A controllable variable electronic time delay apparatus is coupled to each of the electromechanical transducer elements of the array having separate write-in and read-out addressing capabilities. The signals associated with a respective ultrasonic transducer element are fed in at selected write-in addresses and subsequently read-out and extracted after an initial time delay interval. The write-in and read-out address pointers of the memory system are continuously sequenced during operation of the device and the time delay interval is a function of the difference between the addresses and the clock rate.

Abstract: An elastic surface wave recursive filter comprising: one passive resonator formed by two tuned transducers, a means for introducing an elastic surface wave into such resonator, such means being connected to an input of the filter, and a third transducer having the form of a transversal filter, the transducer being coupled to the resonator and connected to an output of the filter.The transfer function of the filter is of the form P(z)/Q(z), the numerator and the denominator being independant.

Abstract: A digital adaptive finite impulse response (AFIR) filter having a large number of coefficients is composed of two or more separate filter units. The first filter unit computes response samples h.sub.o -H.sub.n+1 in response to input signal samples to provide a partial estimated response during each sampling period. After the signal samples are fully processed by the first unit, they are transferred to a second filter unit which produces response samples h.sub.n+2 -h.sub.p+1 in response thereto to provide a second partial response. The sum of the two partial responses is computed to provide the total estimated system response. The two independent filter units thus act simultaneously to provide twice as many coefficients as prior art AFIR filters in the same amount of time.

Abstract: An arrangement for the transmission of audio signals, comprising a delay line (1) provided with 5, 7 or 9 tappings situated at equal time intervals along the delay line. The tappings are each connected to a common adding circuit (16) via an amplitude control device (9 to 13). The ratios between the amplitudes of the output signals of the amplitude control devices, viewed from one end of the delay line (1) to the other end are 1:2n:2n.sup.2 :-2n:1 for five tappings, 1:2n:2n.sup.2 :n.sup.3 -n:-2n.sup.2 :2n:-1 for seven tappings, and 1:2n:2n.sup.2 :n.sup.3 -n:1/4(n.sup.4 -1)-2n.sup.2 :-(n.sup.3 -n):2n.sup.2 :-2n:1 for nine tappings. This yields an arrangement having a flat frequency response from the input (2) to the output (15). The invention also relates to a plurality of delay lines (for example 31 to 35) connected in series and to a reverberation unit provided with such a transmission arrangement.

Abstract: Disclosed is a frequency converting filter comprised of a charge transfer device transversal filter and a non-sampling filter. The transversal filter has an output lead coupled to an input of the non-sampling filter, and has frequency passbands of width .DELTA.f centered at the fixed frequencies nf.sub.s .+-.f.sub.o. The non-sampling filter has a single passband. The single passband has a width of less than f.sub.s -f.sub.o -.DELTA.f/2 and it is centered to include only a selected one of the passbands of the transversal filter.

Abstract: A channel equalizer and ghost cancelling technique are disclosed for removing ghosts from a communications signal which includes a training signal and data. The training signal and its ghosts are processed as a finite length sequence of numbers. The equalizer includes a chain of cascaded filters, the first of which receives the training signal and its ghosts for assuming a filter condition which reduces the finite sequence by two points at the filter's output. Each successive filter in the chain receives the output of an immediately preceding filter and assumes a filter condition in which an additional two points of the finite sequence are eliminated or forced to zero. The filter conditions assumed in response to the training signal and its ghosts are maintained while the data is applied to the filter chain so that ghosts of the type experienced by the training signal are removed from the data.

Abstract: Two analog filters of the second order are arranged in series with a transverse charge transfer filter upstream and downstream of the latter. The analog filters are switched capacitor filters having an amplifier and a network of capacitors and MOS transistors. The filtering device is entirely integrated onto the same semiconductor substrate.

Abstract: Transient data recorder systems including a high speed charge coupled device and a device exerciser, including a high speed sampler and driver circuitry.

Abstract: A transversal filter having an overall impulse response of the form ##EQU1## and producing, from an applied input x(t) an output ##EQU2## where y(t) is obtained by lowpass filtering of a waveform z(t) in use generated in the filter, where z(t) takes the form: ##EQU3## where h.sub.i represents a set of stored coefficients,f(.tau.) is an impulse response accounting for fixed linear filtering at the input and output, independent of the settings h.sub.i, and.delta.(.tau.-.tau..sub.i) is the Dirac delta function defined as a function of time interval .tau. and of a set of time delays .tau..sub.i, where .tau..sub.i is not equal to iT.

Abstract: Room acoustics simulation is achieved by digitally defining delay and weighting parameters and generating sampled analog signal responses. In the early portion of a response term an accurate impulse response is provided and subsequently high echo density is simulated using sampled analog signal Schroeder sections. A sampled data analog signal device is used which employs charge transfer devices as programmable delay media, multiplying digital to analog converters to generate weighting of the analog signal and a general purpose microprocessor as a parameter calculator. The early impulse response characteristic is accomplished by providing a time domain finite impulse response (FIR) section in a transversal filter arrangement which directly feeds to an ultimate output and to parallel comb filter sections which in turn input to at least one all pass section of the so-called Schroeder configuration. The charge transfer devices are employed as programmable delays to propagate the analog signals.

Abstract: A charge coupled device transversal filter having split electrodes each having a sense portion and a complementary dummy portion. All electrode sense portions are coupled to a single sense line and all dummy portions are connected to a reference voltage. Tap weights are determined by relative lengths of successive sense portions and weighted samples are taken by shifting charge packets from one sense electrode position to a second while sensing the difference in displacement charge induced in successive sense electrodes. The structure is less sensitive to manufacturing tolerances than earlier structures and provides a sense signal with essentially no common mode component to a sense amplifier.

Abstract: A SAW signal processor (20) includes a plurality of FET taps (30-32) having individually programmable source-drain bias (42-44) which controls both the amplitude and phase of the mixing efficiency of internal product mixing of the waves passing beneath the tap, in dependence upon the amplitude and polarity of the bias, the sources (34) of the taps may be interconnected so as to provide a summation of correlation at the output (40). The gates (35) of each of the taps are ohmically isolated, thereby to mitigate intertap interaction. The invention is a direct improvement over U.S. Pat. No. 4,207,546.

Abstract: A binary transversal filter which has a plurality of stages of shift registers that are driven by timing signals of a frequency which is a multiple of that of clock pulses being introduced, and a weighting circuit which weights outputs of shift registers of each of the stages, so that outputs of the weighting circuit can be synthesized. The characteristic feature of the present invention resides in the facts that NRZ signals are introduced into the shift registers, and the shift registers are driven by timing signals of a frequency which is a multiple of that of clock pulses of the NRZ signals.

Abstract: A circuit for supplying weighting voltages to multipliers of a transversal filter comprises a plurality of electronic switches associated with the multipliers for switching magnitudes of the weighting voltages applied to the multipliers, and memory cells associated with the respective electronic switches for storing digital data to turn on or off the corresponding electronic switches. Those memory cells are sequentially addressed by address circuits to store data which define the magnitudes of the weighting voltages applied to the multipliers.

Abstract: In a filter in which, in order to obtain the desired filter characteristic, a weighted sum of different signals is formed, it is proposed in accordance with the invention that for the formation of said sum means are employed which are constituted by capacitor circuits, which during a first time interval are each charged by said signals, and by a connection circuit for the formation, during a second time interval, of the equivalent of a single capacitor across whose plates the weighted-sum signal appears.The invention is used for the filtration of sampled analog signals.

Abstract: A recursive digital low-pass filter processes an input signal with essentially unity gain and sharp frequency cutoff without using multipliers to provide an output signal with an information bandwidth substantially one-half that of the input signal.

Abstract: A non-recursive transversal filter circuit employs a charge transfer device in which certain of the capacitive storage elements are divided into first and second capacitive portions having predetermined capacitance relationships. The charge in the second capacitive storage elements is sensed at predetermined times to produce an output signal. The relative capacitances of the second capacitance portions provide weighting factors to the filter. Embodiments include bucket brigade devices with bipolar and FET transistors as well as charge coupled devices.

Abstract: A plurality of MIS charge transfer systems are connected to the output of a first MIS charge transfer system and are operated in parallel with each other. The plurality of charge transfer systems form filters of the same kind, or of a different kind, and charge packets emitted thereby have different delay times and are subsequently converted into a voltage which is sampled at a higher frequency than the sampling frequency for the signal which is applied to the input of the first MIS charge transfer system. This voltage is smoothed by a simple low pass filter.

Abstract: One storage electrode of the filter out of two is cut into two parts. The weighting coefficients are elaborated by reading means connected to a part of each cut storage electrode which read negatively the charges leaving a so-called negative cut storage electrode and positively the charges arriving under the next so-called positive cut storage electrode.

Abstract: A CTD recursive filter includes a single channel with two side-by-side CTD delay lines wherein charges are transferred in opposite directions. Each electrode of the first delay line forms a pair with a corresponding electrode of the second delay line. Each even pair of electrodes are separated from the next odd pair of electrodes by an even bridge electrode occupying the entire width of the channel. Each odd pair of electrodes are separated from the next even pair of electrodes by an odd bridge electrode also occupying the entire width of the channel. An electrode of the first line in an even pair and the electrode of the second line in the next odd pair have lengths the sum of which is a constant. An electrode of the first line in an odd pair and the electrode of the second line in the next even pair have lengths, the sum of which is equal to the constant. At each odd clock pulse, the odd bridge electrode charges are distributed to the closer even bridge electrodes.