A system of automatically transferring vacuum uplift on the top of a roof to the underneath side of the roof membrane to shift the uplift pressure forces into the roof insulation and decking rather than on the roof membrane to prevent upward movement of the membrane and roof layer. A roof structure provided with one or more oneway or duckbill valves placed 3 feet in from the perimeter and on every outside corner at 50 foot intervals, which at their bases open into the area between a loosely laid...

A variable equalizer whose frequency characteristic varies in a range of 1-1/Y(f).sup.2 when the gain x of a variable amplifier varies from 0 (zero) to .infin. (infinity), and which reduces the number of shaping networks for the variable frequency characteristic. It is constructed of a forward pass circuit which consists of a variable amplifier and a frequency-dependent first circuit connected in the order mentioned between input and output terminals, a feedback pass circuit which is dependent u...

A variable equalizer is provided which, using a single variable resistor, can make compensations in both the directions of the gain side, and the loss side and can set a reference gain as desired. An input signal to be equalized is received as an antiphase input signal of a differential amplifier, an output signal which has been equalized is fed back to the antiphase input signal, and a difference signal between an in-phase input signal and the antiphase input signal is delivered as an output. A...

A signal equalizer for equalizing a waveform of a digital data sequence includes a discriminator for discriminating average measurement levels at plural frequencies of the digital data sequence, an error operating unit for finding the ratio or difference between an equalizing target average level which correspond to the plural frequencies that has been found in advance and an average level obtained by the discriminator and a controller for controlling an equalizing characteristic of the equalize...

In an equalizer amplifier of RC attenuation type comprising an RC circuit having RIAA reproduction characteristics, the RC circuit is connected between an input of a first amplifier for amplifying an output signal of the RC circuit and an output of a second amplifier for amplifying an output signal of the first amplifier. One of the amplifiers is a noninverting amplifier, and the other is an inverting amplifier. So constituted, the equalizer amplifier increases apparently impedances of RC elemen...

An equalizer introduces into the attenuation versus frequency curve of a signal carrier transmission system compensatory bumps of adjustable magnitude and of adjustable frequency location. When the bumps are in their initial frequency locations, they exhibit the following features: (a) The middle frequencies of the bumps are each shiftable with respect to frequency by an amount equal to at least one half the frequency interval to the respective neighboring bump. (b) Adjoining bumps of equal magn...

A variable equalizer for compensating for the frequency characteristics of transmission media, comprising a plurality of variable circuits which are connected in cascade to an input terminal and which have the same variation characteristics, coefficient circuits which receive input and output signals of the variable circuits as inputs thereof and which multiply the inputs by coefficients, a plurality of impedance circuits which receive as inputs thereof signals with outputs of the coefficient ci...

An amplitude equalizer is provided for equalizing amplitude distorted signals within a predetermined frequency band. The amplitude equalizer comprises first means for splitting signals into first and second split signals. A first delay device receives one of the two split signals, and a second signal splitter splits the output of the first delay device into third and fourth split signals, the third split signal being applied to a second delay device having a delay equal to the delay of the first...

An automatic equalizer comprises a transversal filter for receiving an input signal to be equalized and having adjustable tap gains, a circuit connected to receive an output signal of the transversal filter and the input signal to be equalized to produce an equalized output signal, a distortion detect circuit for detecting a distortion component included in the output signal, a tap gain correct circuit connected to receive a distortion detect signal from the distortion detect circuit to produce ...

An amplitude equalizer includes a pair of serially connected unit amplitude equalizers, each having complementary delay distortion characteristics to flatten the overall delay distortion characteristic. The unit equalizers include amplifiers or attenuators, delay circuits, and/or phase shifters. The amplitude versus frequency characteristic of the overall equalizer can be varied by controlling one or more of the attenuator/amplifiers and phase shifters. The variation can be controlled by a feedb...