摘要:
In a tape recorder, when a magnetic tape changes its transportation speed for special reproduction, either one of a phase reference signal and a magnetic tape transportation phase signal representing the transportation phase of the magnetic tape is delayed by a delay circuit so that the signal not passing therethrough is compared with that having passed through the delay circuit, at which time the delay time of delay circuit is changed corresponding to the transportion speed of the magnetic tape so as to carry out phase control, thereby obtaining the optimum tracking in the reverse normal, double, and triple speed reproduction modes.
摘要:
A driving apparatus for driving a passive matrix liquid crystal display utilizing an active driving method includes an image buffer storage for storing one frame of image data in the form of a matrix to output image data on a column by column basis to produce a rearranged image data. A matrix generator generates row data. A data converter multiplies the rearranged image data with row vectors to produce converted data. A converted data buffer storage stores the converted data and outputs the data on a row by row basis to produce a column data. A LCD driver is provided for producing a column signal based on the column data and a row signal based on the row data, and further for applying these row and column signals to row and column electrodes, respectively, to drive the LCD.
摘要:
A digital oscillation apparatus includes a data generator and an accumulator which function as follows. The data generator is responsive to each clock of a clock signal having a frequency fc for generating data used to generate a data string which has a total value R (R is an integer) in a repetition period of m clocks (m is an integer). Accordingly, the average value of each data of the data string generated in response to each clock becomes R/m. The accumulator has a dynamic range D (D is an integer) and is responsive to each clock of the clock signal for accumulating a sum of each data (average value=R/m) of the data string generated by the data generator and a constant A (A is an integer) until the accumulated result exceeds the dynamic range. That is, data having an average value A+R/m is accumulated in response to each clock of the clock signal. When the accumulated result exceeds the dynamic range D, the accumulator subtracts the dynamic range D from the accumulated result, or resets the accumulated result. If the values of R, m, A and D are set to satisfy a relationship of fs/fc= (A+R/m)D, where fs is a frequency of a periodic waveform data to be generated as an output of the apparatus, the accumulator generates periodic waveform data having a frequency fs=(A+R/m).multidot.fc/D.
摘要:
A magnetic reproducing apparatus which has a pair of main rotatable heads having different azimuth angles and a pair of auxiliary rotatable heads having different azimuth angles. When a magnetic tape is played back while it runs at a speed different from that at which it runs during a recording mode, playback output signals from the main and auxiliary rotatable heads are switched over to replace a reduction in the outputs from the main rotatable heads with the outputs from the auxiliary rotatable heads to produce a combined playback output signal. The combined playback output signal is passed through a variable delay line having a delay time varied by an output from a detector circuit which detects variations in horizontal synchronous signal intervals of the combined playback output signal. This varied delay time of the variable delay line can eliminate any skew distortions which would appear on a displayed image on the screen due to the variations in horizontal synchronous signal intervals of the combined playback output signal.
摘要:
In a phase error detector for detecting a phase error .theta. of an input color burst signal from a phase of a reference signal from sin .theta. component and cos .theta. component, if either one of the sin .theta. component and cos .theta. component requires M bits for its expression, the both values are divided by a same value to shift in bits to be expressed in N bits (N
摘要:
In a system for eliminating time base fluctuation of a video signal having a synchronizing signal and a burst reproduced from a video disk, for example, the synchronism is first coarsely pulled in on the basis of the horizontal synchronizing signal and then precisely follows the time base fluctuation on the basis of the burst signal. A shift of the output synchronizing signal is corrected by using a phase detection of an input horizontal synchronizing signal when an output synchronizing signal is produced on the basis of the read address of a memory for eliminating time base fluctuation, thereby preventing, for example, a superimposed character using the output synchronizing signal from fluctuating on a picture.
摘要:
A digital phase locked loop for correcting the phase of an output signal with respect to an input signal has a phase comparator for comparing the phases of the input signal and a feedback signal from a variable frequency oscillator. The output signal of the phase comparator representing the phase difference is integrated in a low pass filter. The output of the low pass filter is supplied to a switch which alternately selects between the output of the low pass filter and a zero level signal from a zero generator. The output of the switch is supplied to the variable frequency oscillator. The output signal of the variable frequency oscillator is returned to the phase comparator, so that the phase of the output signal from the variable frequency oscillator is synchronized with the phase of the input signal.
摘要:
A low-range-converted chrominance signal is demodulated into two color difference signals. The two color difference signals are each filtered by a comb filter to eliminate undesired components. The two color difference signals, having been filtered, are modulated to obtain a carrier chrominance signal having a prescribed carrier frequency. To be suitable for digital signal processing, the low-range-converted chrominance signal is sampled at a first frequency which is an integral multiple of a low-range-converted carrier frequency of the low-range-converted chrominance signal when being demodulated. The two color difference signals are sampled at a second frequency which is an integral multiple of the prescribed carrier frequency of the carrier chrominance signal.
摘要:
A digital automatic gain control apparatus is provided which controls gain such that when an analog video signal is converted into digital signals for processing, the input of the A-D converter is maintained at a fixed level, and after the analog signal has been converted into digital form, the output of the digital system circuit is also maintained at a fixed level. In this apparatus, an input signal is passed through an analog variable gain amplifier, the signal is converted into digital form, and the output of an A-D converter is passed through a digital variable gain amplifier. The amplitude level of the output of the digital variable gain amplifier is detected by an amplitude detecting unit and is controlled so as to be equal to a specified reference value. At this time, the analog variable gain amplifier is controlled so that the level of the control signal for controlling the digital variable gain amplifier is equal to a specified reference value, thereby maintaining the signal of the A-D converter at a fixed level. Gain control of the analog signal system and the digital signal system, before and after the A-D converter, is effected by a single amplitude detecting unit.
摘要:
A disclosed time base corrector comprises a clock generater for generating a clock signal whose period is fixed, an analog-to-digital converter for sampling amplitude values of an input analog signal having a time base error at sampling points given by the clock signal, an adaptive interpolation filter for interpolating a correct amplitude value at a resampling indicated by a resampling position signal, a resampling position signal producing circuit for detecting the time base error and producing from the detected error the resampling position signal, and a digital-to-analog converter for converting the interpolated amplitude values to an analog signal which has no time base errors. The time base correction is implemented by pure digital signal processing without any analog signal processing. The time base corrector does not use such a clock signal that has time base fluctuations.