Abstract: This invention relates to a video image reproducing apparatus operable to reproduce a video image signal recorded on a magnetic tape through a field memory at a different speed from a recording speed. An envelope detecting signal of a reproducing signal from a magnetic head is compared with a reference potential by a comparator in order to automatically control the write timing to the field memory. The reference potential is adjusted based on an output signal of the comparator. The write timing to the field memory is controlled in accordance with an output signal of the comparator which compares the envelope detecting signal with the adjusted reference voltage. The apparatus of the invention is to be used in a video tape recorder.

Abstract: A frequency demodulator which comprises a digital FM demodulating circuit for demodulating an inputted FM signal and outputting a digital demodulated signal, a discriminator for discriminating whether or not the value of the digital demodulated signal from the digital FM demodulating circuit deviates from an upper limit value or a lower limit value set for a normal demodulating range, and a circuit operable on the basis of a result of the discrimination performed by the discriminator for replacing the value of the demodulated signal deviating from the upper limit value or the lower limit value with a compensation value set to a value approximating the upper limit value in the case where the inputted FM signal which has been demodulated is of a type having upper and lower side-bands suppressed and emphasized, respectively, or with a compensation value set to a value approximating the lower limit value in the case where the inputted FM signal which has been demodulated is of a type having upper and lower side-b

Abstract: A frequency demodulator includes an analog-to-digital converter for converting an inputted FM signal into a digital signal. A 90.degree. phase shifter is used to phase shift the converted digital signal. The phase shifted signal and the converted signal are utilized to determine the results of tan.sup.-1 (X/Y). X represents the converted signal, and Y represents the phase shifted signal. The result from the calculation is delayed for a period of time equal to one sampling cycle. The frequency demodulator also includes a subtractor for subtracting the delayed signal from the calculation result. A discontinuity corrector corrects any discontinuity in an output from the subtractor, and a reversal phenomenon compensator compensates the output from the discontinuity corrector when the output from the discontinuity corrector exceeds a predetermined range of levels. These levels correspond to an appearance of discrete lines of black or white color on a reproduced picture.

Abstract: An air fuel ratio control apparatus, performs fuel decrease compensation during deceleration with respect to an air fuel ratio upon detection of a returning operation of a throttle valve. To avoid variations in torque which detract from a smooth ride, fuel decrease compensation is prohibited under the conditions that the opening of the throttle valve is in a full opening region and the amount of return movement of the throttle valve per unit time is equal to or less than a preset valve.

Abstract: A video recording and reproducing apparatus which is designed to store a reproduced signal in a field memory when a level of the signal reproduced from the recorded magnetic tape is larger than a previously established predetermined level and to read out the stored content, including detection, circuit for measuring the recording track width on the basis of an envelope detection signal of the reproduced signal which is obtained when the magnetic head traverses the recording track on said magnetic tape; and a circuit for establishing said predetermined level at a level optimum to the reproduction of the signal on the basis of the measured result.

Abstract: An amount of fuel fed to an engine and determined by the rpm of the engine and a suction air flow rate is increased by a predetermined amount of fuel upon detection of acceleration. When the engine is suddenly accelerated from a low-speed operational region to enter a power zone, the above-mentioned predetermined amount of fuel is corrected based on the rpm of the engine and a quantity of change in the throttle valve opening degree.

Abstract: A fuel is injected based on the rpm of the engine and the suction air rate. The fuel injection amount is corrected depending on a map of fuel injection share correction coefficient prepared in advance and determined by data such as a throttle valve opening and the rpm of the engine so that amounts of fuel injected will be even at the respective cylinders. The fuel injection share correction coefficient is for correcting fuel deviation due to construction of suction passage to with the respective cylinders or for correcting fuel deviation due to arrangement of two injectors in one bore with respect to the throttle valve shaft.

Abstract: Disclosed is a fuel control apparatus in an internal combustion engine. When the running mode the engine is changed into acceleration again from deceleration after acceleration, the fuel becomes too rich if the conventional continuous correcting factor is used. In order to properly reduce the quantity of fuel supply in that case, the number of engine revolutions is counted from a point of initiation of deceleration to a point of initiation of acceleration again to thereby calculate a proper value of the continuous correcting factor corresponding to the count, so that fuel is supplied to the internal combustion engine with a quantity corrected by the thus calculated value of the continuous correcting factor.

Abstract: The supercharger pressure control system includes a sensor for detecting the supercharger pressure of the engine and regulates the pressure through a variable geometry device or an exhaust bypass valve. The control for the pressure regulation is carried out by comparing the sensed supercharge pressure with a target value. Any difference determined by this comparison is accumulated by a computer as an error and a basic control value is determined based on the error. Alternatively, a predetermined basic control value for the engine intake air is corrected in accordance with the error and this control value or corrected value is used to control the operation of the supercharge pressure regulator. This causes the regulator to operate in a manner responsive to variations in performance of the engine or turbocharger, thus maintaining the supercharged pressure within a permissible range of a target value.

Abstract: An apparatus for controlling a turbocharger includes a compressor and a turbine coupled to the compressor and comprises a variable capacity device for varying the flow rate of an exhaust gas introduced into the turbine in the low speed state of an engine connected to the turbocharger, an exhaust gas bypass device bypassing the variable capacity device and the turbine to control the flow rate of the exhaust gas in the high speed state of the engine, and an overboost device for detecting the accelerating state of the engine and controlling the operation of the exhaust gas bypass device such that the exhaust gas bypass device reduces the flow rate of the exhaust gas introduced into the turbine only when the supercharging pressure has reached a predetermined pressure in the accelerating state of the engine.