An analgesic noise generator employs a circuit that can be switched to provide a variable waveform from an active noise source out of an integrated circuit amplifier.

Noise generator and transmitter

The present invention relates to a modulator for use in the carrier frequency techniques. The modulator includes a voltage controlled impedance element with two control electrodes, as for example a dual gate field effect transistor, in order to carry out a modulation of a carrier frequency voltage with an information signal voltage. The carrier frequency voltage is applied to one of the control electrodes of the impedance element and the information signal is applied via a resistor to the output electrodes of the element. In order to reduce the disturbing influence of the second side-band components in the frequency spectrum of the modulated signal, a voltage divider is connected across the output electrodes of the impedance element, one point on this voltage divider being connected to the second electrode of said impedance element.

Modulator, included in a carrier frequency system wherein the carrier signal periodically interrupts the information signal during the modulation process

An amplitude modulator using an FET, or MOSFET and a coupling and phase splitting device capable of accepting both single ended and balanced inputs (like for example, a differential amplifier or a center tapped choke coil, or a transformer). The source and drain terminals are connected to the differential inputs (outputs) of the device, and the signal to the single ended input of the device. The carrier is applied to the gate terminal of the FET or MOSFET. The switching action of the device is equally efficient for both single ended and differential inputs (outputs). However, the carrier leak voltage is being applied simultaneously to both terminals of the differential input and thus suppressed in the output by virtue of high suppression of longitudinal (common) mode pertinent to devices with differential inputs (outputs). Other modulators are disclosed including a double balanced modulator using two complimentary field effect transistors and a double balanced modulator using two field effect transistors of the same conductivity type.

Modulator and method

A device code recognizing circuit includes a microprocessor forming an array having input pins and output pins and a code generation circuit connected to the microprocessor. The code generation circuit includes signal input terminals connected to input pins of the array and signal output terminals connected to I/O terminals of the microprocessor. The signal output terminals are sequentially and selectively set to one of low level condition and high impedance condition. The input pins of the microprocessor to which the signal input terminals of the code generation circuit are connected serially read signals from the code generation circuit for provision the signals to the microprocessor to form a device code associated therewith.

Device code recognizing circuit

A tuner, a broadcast signal processing apparatus and method, which satisfy reception sensitivity of both terrestrial and cable televisions, when selecting a broadcast signal through a single conversion tuner, are provided. A tuner selects a broadcast signal of a selected channel. The tuner includes an input filter that filters a received broadcast signal into plural frequency bands based on a predetermined frequency band. An amplifier amplifies a second signal having an original phase induced by an output signal of the respective frequency bands, and a first signal having an opposite phase of the second signal, and outputs the signal induced by the amplified first and second signals as an amplification signal of the signal in the respective frequency bands. An inter-stage filter filters a frequency of the broadcast signal corresponding to the selected channel among the amplification signals output from the amplifier. A converter converts the broadcast signal of the frequency filtered by the inter-stage filter.

Tuner, broadcast signal processing apparatus comprising the same, and broadcast signal processing method

A modulator circuit employing two dual gate field effect transistors. A carrier signal is applied to one gate of each transistor in a push-pull arrangement. A modulating signal is applied to the other gate of each transistor in parallel. The modulated output signal appears between the drains of the transistors.

Paglee Mario Robert

Papers

Field effect transistor modulator circuit