SUMMARY / RELATED TOPICS

Overshoot (signal)

In signal processing, control theory and mathematics, overshoot is the occurrence of a signal or function exceeding its target. It arises in the step response of bandlimited systems such as low-pass filters, it is followed by ringing, at times conflated with the latter. Maximum overshoot is defined in Katsuhiko Ogata's Discrete-time control systems as "the maximum peak value of the response curve measured from the desired response of the system." In control theory, overshoot refers to an output exceeding its steady-state value. For a step input, the percentage overshoot is the maximum value minus the step value divided by the step value. In the case of the unit step, the overshoot is just the maximum value of the step response minus one. See the definition of overshoot in an electronics context. For second order systems, the percentage overshoot is a function of the damping ratio ζ and is given by P O = 100 ⋅ e The damping ratio can be found by ζ = 2 π 2 + 2 In electronics, overshoot refers to the transitory values of any parameter that exceeds its final value during its transition from one value to another.

An important application of the term is to the output signal of an amplifier. Usage: Overshoot occurs when the transitory values exceed final value; when they are lower than the final value, the phenomenon is called "undershoot". A circuit is designed to minimize risetime while containing distortion of the signal within acceptable limits. Overshoot represents a distortion of the signal. In circuit design, the goals of minimizing overshoot and of decreasing circuit risetime can conflict; the magnitude of overshoot depends on time through a phenomenon called "damping." See illustration under step response. Overshoot is associated with settling time, how long it takes for the output to reach steady state. See the definition of overshoot in a control theory context. In the approximation of functions, overshoot is one term describing quality of approximation; when a function such as a square wave is represented by a summation of terms, for example, a Fourier series or an expansion in orthogonal polynomials, the approximation of the function by a truncated number of terms in the series can exhibit overshoot and ringing.

The more terms retained in the series, the less pronounced the departure of the approximation from the function it represents. However, though the period of the oscillations decreases, their amplitude does not. For the Fourier transform, this can be modeled by approximating a step function by the integral up to a certain frequency, which yields the sine integral; this can be interpreted as convolution with the sinc function. In signal processing, overshoot is when the output of a filter has a higher maximum value than the input for the step response, yields the related phenomenon of ringing artifacts; this occurs for instance in using the sinc filter as an ideal low-pass filter. The step response can be interpreted as the convolution with the impulse response, a sinc function; the overshoot and undershoot can be understood in this way: kernels are normalized to have integral 1, so they send constant functions to constant functions – otherwise they have gain. The value of a convolution at a point is a linear combination of the input signal, with coefficients the values of the kernel.

If a kernel is non-negative, such as for a Gaussian kernel the value of the filtered signal will be a convex combination of the input values, will thus fall between the minimum and maximum of the input signal – it will not undershoot or overshoot. If, on the other hand, the kernel assumes negative values, such as the sinc function the value of the filtered signal will instead be an affine combination of the input values, may fall outside of the minimum and maximum of the input signal, resulting in undershoot and overshoot. Overshoot is undesirable if it causes clipping, but is sometimes desirable in image sharpening, due to increasing acutance. A related phenomenon is ringing, following overshoot, a signal falls below its steady-state value, may bounce back above, taking some time to settle close to its steady-state value. In ecology, overshoot is the analogous concept, where a population exceeds the carrying capacity of a system. Step response Ringing Settling time Damping Overmodulation Integral windup Percentage overshoot calculator

T-40 (tractor)

From 1961 until 1995 the T-40 was a farm tractor built by the Lipetsk Tractor Plant. The T-40 was designed for plowing light soil, processing row crops, plowing snow and for transportation. To achieve these goals, it has a carrier transmission and rear axle, a more rigid connection between the engine and the transmission case, increased diameter of the rear drive wheels, smaller front guide wheels and stiffer suspension than other tractors, its durability has enabled many of the tractors produced in the 70's - 80's to remain in operation. Spare parts are still being produced; the T-40 was produced by the Vladimir Tractor Plant. The tractor has four-cylinder four-stroke diesel air-cooled engine: D-144 50 hp. Depending on configuration, an electric starter or a gasoline starting engine, were used to start the diesel engine, it was manufactured in four-wheel drive and rear-wheel drive versions. It has an adjustable gauge and adjustable ride height on all wheels; the T-40 can be fitted with removable rear wheels of reduced width to work in aisles.

In order to work on steep slopes, the track width can be increased by installing the rear wheels inside out. The T-40 had a reversible manual transmission, allowing the use of the full range of speeds both forward and backward. A bevel gear was placed after the clutch and a mechanical or hydrostatic reduction gear, which enabled it to operate at low speeds, it had two PTO shafts - side. These features, as well as its good performance, led to the tractor being adopted throughout the USSR; the engine is air-cooled which reduces the risk of freezing. Tractors with D-37 and D-144 engines had differently shaped hoods; the former had a rounded hood. T-40 - basic model - rear-wheel drive, engine D-37 T-40A - all-wheel drive T-40AN - all-wheel drive with reduced height and less ground clearance for slopes T-50A - Industrial modification for shovel loading T-40M - rear-wheel drive T-40AM - all-wheel drive T-40ANM - all-wheel drive and reduced ground clearance for slopes T-40AP - all-wheel drive designed for communal facilities Photos tractor T-40, T-40A Photos of tractors T-40M and its modifications

Cloak Without Dagger

Cloak Without Dagger is a 1956 British thriller film directed by Joseph Sterling and starring Philip Friend, Mary Mackenzie and Leslie Dwyer. It was released as Operation Conspiracy A fashion reporter is united with a former boyfriend, after a chance meeting, helps him to track down an enemy spy. Philip Friend - Major Felix Gratton Mary Mackenzie - Kyra Gabaine Leslie Dwyer - Fred Borcombe Allan Cuthbertson - Colonel Packham John G. Heller - Peppi Gilroudian Dress Designer Chin Yu - Yan Chu Bill Nagy - Mario Oromonda Patrick Jordan - Captain Willis Marianne Stone - Mrs. Markley Frank Thornton - Mr. Markley Gerrey Levey - Night club entertainer Boris Ranevsky - Antoine María Mercedes - Spanish girl Patricia Haynes - Marigold Larry Taylor - Sergeant Blake The Radio Times described it as "an uncomfortable mix of romance and mystery". Cloak Without Dagger on IMDb