Abstract: A smart card with improved power stability is provided.

Abstract: An object is to provide a demodulation circuit having a sufficient demodulation ability. Another object is to provide an RFID tag which uses a demodulation circuit having a sufficient demodulation ability. A material which enables a reverse current to be small enough, for example, an oxide semiconductor material, which is a wide bandgap semiconductor, is used in part of a transistor included in a demodulation circuit. By using the semiconductor material which enables a reverse current of a transistor to be small enough, a sufficient demodulation ability can be secured even when an electromagnetic wave having a high amplitude is received.

Abstract: A demodulation circuit for an Amplitude Shift Keyed (ASK) modulated signal includes an envelope detector, an alternating voltage amplifier, a differentiator circuit, and a comparator having a hysteresis connected in series. The envelope detector produces an envelope signal from the received ASK signal. The amplifier blocks the DC component of the envelope signal and amplifies AC components of the envelope signal to obtain a steeper slope of the rising and falling edges. The differentiator circuit then processes the transition edges to provide a differentiated signal having positive and negative electrical pulses. The comparator converts the pulses into a binary data stream which corresponds to the transmitted data stream. The combination of the differentiated signal and comparator having a hysteresis enables better stability and sensitivity of the ASK demodulation circuit.

Abstract: An object is to provide a demodulation circuit having a sufficient demodulation ability. Another object is to provide an RFID tag which uses a demodulation circuit having a sufficient demodulation ability. A material which enables a reverse current to be small enough, for example, an oxide semiconductor material, which is a wide bandgap semiconductor, is used in part of a transistor included in a demodulation circuit. By using the semiconductor material which enables a reverse current of a transistor to be small enough, a sufficient demodulation ability can be secured even when an electromagnetic wave having a high amplitude is received.

Abstract: A semiconductor device is provided, which comprises a first demodulation circuit, a second demodulation circuit, a first bias circuit, a second bias circuit, a comparator, an analog buffer circuit, and a pulse detection circuit. An input portion of the pulse detection circuit is electrically connected to an output portion of the analog buffer circuit, a first output portion of the pulse detection circuit is electrically connected to an input portion of the first bias circuit, and a second output portion of the pulse detection circuit is electrically connected to an input portion of the second bias circuit.

Abstract: A demodulation circuit, including: an input terminal (IN) inputting a current amplitude modulated signal; a first transistor (101) connected to the input terminal; a capacitance (105) connected to a control terminal of the first transistor; a diode (102) connected between the input terminal and the control terminal of the first transistor; and a first current source (104) applying a current of the input terminal, is provided.

Abstract: A modulation ratio enhancement circuit increases the modulation ratio of a current signal which is ASK-modulated with signal data. A branch unit, an average value detection unit, a comparator and a buffer constitute a demodulation unit so that the signal data is demodulated from a current signal of which the modulation ratio is increased by the modulation ratio enhancement circuit.

Abstract: A shunt regulator performs a control so as to stabilize a voltage obtained by rectifying the radio frequency signal output from an antenna unit at a prescribed voltage value. A signal extraction unit extracts the information signal from a bypass current sent by the shunt regulator for the control when the voltage fluctuates.

Abstract: In a contactless IC card system, a modulating circuit manufactured in an IC form is operable at a high power efficiency. The demodulating apparatus is configured to include: signal processing means for producing first and second input signals; first clamping circuit for clamping said first input signal; second clamping circuit for clamping said second input signal; first band limiting means for removing a component of said first input signal from an output signal of said first clamping circuit; second band limiting means for removing a component of said second input signal from an output signal of said second clamping circuit; and calculating means for adding, or averaging an output signal of said first band limiting means and an output signal of said second band limiting means.

Abstract: A shunt regulator performs a control so as to stabilize a voltage obtained by rectifying the radio frequency signal output from an antenna unit at a prescribed voltage value. A signal extraction unit extracts the information signal from a bypass current sent by the shunt regulator for the control when the voltage fluctuates.

Abstract: A diode detector comprising a detector network adapted to detect and multiply the detected voltage coupled to a divider network that comprise diodes in equal number to the number of diodes in the detector network, provides a passive detector applicable to any application requiring a small, efficient, high output, inexpensive temperature compensated detector for use as demodulator or as power to voltage converter. Integrating a portion of the divider network in the detector/multiplier network allows control over the minimum input impedance of the detector.

Abstract: A diode detector comprising a detector network adapted to detect and multiply the detected voltage coupled to a divider network that comprise diodes in equal number to the number of diodes in the detector network, provides a passive detector applicable to any application requiring a small, efficient, high output, inexpensive temperature compensated detector for use as demodulator or as power to voltage converter.

Abstract: A demodulator converts a voltage input to an output voltage. The demodulator has a voltage-controlled oscillator (VCO), a counter, a holding apparatus, and a digital compare apparatus. The VCO generates a signal having a frequency proportional to the analog input voltage. The counter counts each cycle of the signal generated by the VCO and outputs a count signal representative of the cycle count. The holding apparatus holds the count signal and generates a held count signal. The digital compare apparatus compares the count signal and the held count signal and generates the digital output.

Abstract: A demodulator circuit for demodulating a signal ASK-modulated with modulation pulses equal in duration, and having a small depth of modulation and large dynamic range comprises an amplitude limiter (10) through which an amplitude-dependent current flows when the amplitude of the signal to be demodulated exceeds its limiting threshold value. Furthermore comprised is an envelope detector (12) to the input of which the signal to be demodulated is applied, as well as a differentiating network (14) configured so that it differentiates the output signal of the envelope detector (12) and outputs a signal pulse only when the change in amplitude of this output signal is in one direction. A bandpass filter (18) in the demodulator circuit passes, from a signal derived from an amplitude-dependent current from the amplitude limiter (10), the frequency component attributed to the duration of the modulation pulses.

Abstract: Apparatus and method for fabricating a backside illuminated photodiode array is described which does not use epoxy, and therefore has better transmission characteristics. The method uses indium or other coldweldable metal to fasten the detectors to the transmissive substrate. Because the indium is opaque in the waveband of detector sensitivity, it also forms an optical mask for each detector element.

Abstract: A controlled detector circuit for generating a detector current to the input of a selected circuit. An unwanted operational voltage is generated on the input of the selected circuit affecting the precision of the detector circuit. The controlled detector circuit comprises a detector circuit having an RF input for detecting a RF signal and a detector output for providing the detector current. Operation of the detector circuit generates a voltage drop affecting the precision of the detector current. A control circuit having a control output connected to the detector output generates a control voltage for reducing the unwanted parameters affecting the precision of the detector current.

Abstract: The invention is directed toward a simple and cost effective method of wirelessly transmitting digital information with an analog carrier signal. The method, referred to as Interrupt Modulation IM, will allow broadcasters to make the transition from an analog to a digital format while using existing analog equipment and conserving radio spectrum. Interrupt Modulation consists of allowing digital information to be transmitted to control a high speed analog special interrupter circuit which interrupts the circuit path of an unmodulated carrier signal such that the analog carrier is interrupted to directly correspond with the time length of the high segment of the digital pulse wave. Digital information is then transferred by the absence of the analog carrier signal. As modern high speed analog switches are capable of on/off operation at speeds of several megahertz, which is common in digital information computers, throughout rates of up to 100 megabits per second are obtainable.

Abstract: The present invention provides a detector comprising a microstrip line having one end being grounded and another end connected to a main transmission line, a detection diode connected to the microstrip line, and a smoothing circuit for smoothing a signal detected by the detection diode.

Abstract: A contactless chip card, receiving binary data transmitted by radio frequency, includes a demodulator for the binary data. The demodulator includes a circuit for the detection of the transmitted signals, a rectifier circuit, a bandpass filter, two comparators and a memory circuit. The bandpass filter provides a low-frequency signal used as a reference for the two comparators and a high-frequency signal that is compared with the references varying with the low frequency signal. As a result, the demodulation is independent of the mean level of the received signal.

Abstract: An enhanced peak detector circuit for the amplitude demodulation of an incoming amplitude modulated signal is provided. In its simplest form, the enhanced peak detector circuit includes a forward biased NPN transistor, a peak detecting segment coupled to the base-emitter junction of the transistor; and a peak holding capacitor leading from the collector of the transistor and connected in parallel to the peak detecting segment. The peak detecting segment includes a parallel connected peak detecting capacitor and a resistor. When the base-emitter junction of the transistor is conducting, both the peak detecting capacitor and the peak holding capacitor are charging. Conversely, when the base-emitter junction of the transistor is back biased, the peak detecting capacitor discharges through the resistor and the collector remains open such that the peak holding capacitor remains charged.

Abstract: A DC coupled amplifier fed by an RF detector is taught which has greater dynamic range capabilities than techniques in the prior art. An illustrative embodiment of the present invention advantageously comprises a low-off set voltage, low-offset current differential amplifier fed by an RF detector having a fifth lead from the reference voltage node within the RF detector.

Abstract: The disclosure relates to the servo-control of an electronic circuit that calls for the detection of the power delivered at its output. The disclosed device is essentially constituted by a field-effect transistor with zero bias V.sub.DS mounted between the ground and a matching network at output of the circuit. This transistor behaves either like a capacitor or like a diode. A low-pass filter, connected between the transistor and the network, delivers a detection voltage V.sub.det.

Abstract: A superconducting non-linear device comprising a superconducting conductor, a current source associated with the conductor for applying to the conductor a bias current, and a control device associated with the current source for selectably varying the bias current between a first value below the critical current for the conductor means and a second value above the critical current. The non-linear device is a switching device comprising a switching element in the form of a superconducting film, a terminal for inputting a signal to the switching element, a terminal for outputting a signal from the switching element, and a circuit for applying a DC bias current to the switching element and for causing the DC bias current to vary between a first value below the critical current for the superconducting film and a second value above the critical current.

Abstract: Envelope detector comprising a differential amplifier (A), a full-wave rectifier circuit and a smoothing filter (AF), which differential amplifier (A) converts an input voltage into a pair of current signals in phase opposition and which full-wave rectifier circuit comprises a pair of half-wave rectifiers (HWR1, HWR2) for half-wave rectifying the said pair of current signals, coupled to a first combining stage (S) for combining the output signals of the two half-wave rectifiers (HWR1, HWR2) with like polarity, which first combining stage (S) supplies a full-wave rectified signal. In order to reduce d.c. offsets, the detector comprises a frequency-dependent negative feedback loop which comprises a second combining stage (D) coupled to the outputs (R.sub.o1, R.sub.o2) of the pair of half-wave rectifiers (HWR1, HWR2) for combining the output signals of the pair of half-wave rectifiers (HWR1, HWR2) with opposite polarity, said second combining stage (D) being negatively fed back to the input (I.sub.

Abstract: A temperature stabilized RF detector has a first diode connected between an input terminal for receiving an RF signal and an output terminal for outputting the detection signal of the RF signal, and a second diode connected between the input terminal and a constant voltage source through a buffer circuit. Connecting directions of the first and second diodes are opposite to each other in a circuit for connecting the output terminal and the constant voltage source.