A speaker system is disclosed which comprises a woofer, a transformer secondary and a plurality of inductive and capacitive impedances. Switching means are provided for coupling selected taps of the transformer secondary through selected ones of the impedances so as to selectively add or subtract, according to the switch position, the amount of sound power output.

An equalizer comprising a pair of high pass filters for receiving an input signal, each filter having gain, a first of the filters having gain which is substantially flat within its passband, a second of the filters having gain over a range of its passband which is controlled by an error signal, a differential amplifier for generating the error signal, having an output applied to a control input of the second filter, a pair of broadband amplitude peak detectors each for receiving an output signa...

An inductorless variable equalizer comprises input and output terminals. A first transmission network is situated in the forward path between the input and output terminals and has a variable transfer coefficient; second and third transmission networks are situated in the feedback and feedforward paths, respectively, between the input and output terminals. Each of these networks has a fixed transfer coefficient and the transfer coefficients of the feedback and feedforward networks having polarit...

In order to avoid a floor phenomenon of an error rate without insertion of a datum signal, a fading equalizer, for which it is assumed that a series of symbols that represent quadrature detect output are I(n) and Q(n) (n: natural number) and an assumed maximum fading frequency is F(max), and which demodulates a modulation wave that is to be transmitted whose data are carried by phase or amplitude modulation, or both, of a radio frequency carrier, includes a symbol extractor, for performing sampl...

An adaptive equalizer which has a decision feedback adaptive equalizer unit 41, a linear adaptive equalizer unit 42, comparing circuit 47 which compares integrated equalizing error value of the decision feedback adaptive equalizer 41 with integrated estimation error value of the linear adaptive equalizer unit 42, and selecting circuit 48. The selecting circuit 48 selects one of the equalizer units 41 and 42, which has the better performance based on the result of the comparison of comparing circ...

An optical equalizer comprises a plurality of serially concatenated filter elements the phase and modulation depth of which can be individually tuned. The filter elements are tuneable in order to generate a desired optical equalization function. Each of the filter elements is a three arm interferometer and each is fabricated utilizing integrated waveguide technology.

To form a simple and economical variable equalizer, the equalizer is constructed of a differential amplifier having two input terminals to which an input signal to be equalized and an equalized output signal derived from the output terminal are applied, a first impedance circuit connected between the differential amplifier and the output terminal, and a series circuit having a second impedance circuit and a variable resistor connected in series between the output terminal and a ground terminal.

A variable equalizer wherein a series circuit which consists of a voltage source and an impedance circuit having an impedance Z.sub.x is connected in parallel with a circuit for changing an input voltage into a current, and an impedance circuit having an impedance Z.sub.y is also connected in parallel with this current source. The voltage value of the voltage source is made one which is obtained by multiplying the current by a value proportional to 1/Z.sub.y, and the impedance circuit having the...

A Bode equalizer which has as one active element thereof a high-gain, differential-input amplifier and which has as a second active element a variable negative resistance, the equalizer circuit being controlled by a resistance arrangement which effectively comprises a series-connected, fixed resistor and the variable negative resistance.

Apparatus for coordinating the transfer of two continuous cords or strips includes a first roll for delivering a first cord or strip, a second roll for delivering a second cord or strip, a drive for the first roll, a drive capable of operating the second roll at speeds different from that of the first roll, and a tension-detecting control arrangement for detecting changes in the tension of the cord or strip being delivered by the first roll and changing the speed of the second roll in response t...