Abstract: A clock-generating circuit for forming internal clock signals by comparing a signal obtained by delaying, through a variable delay circuit, an input clock signal input through an external terminal with the input clock signal through a phase comparator circuit, and so controlling the delay time of the variable delay circuit that they are brought into agreement with each other, wherein the clock-generating circuit and an internal circuit to be operated by the clock signals formed thereby are formed on a common semiconductor substrate, and an element-forming region in which the clock-generating circuit is formed is electrically isolated from an element-forming region in which the digital circuit is constituted on the semiconductor substrate relying upon the element-isolation technology. The power-source passages, too, are formed independently of other digital circuits.

Abstract: To provide a phase locked loop circuit that is capable of performing an automatic adjustment that satisfies a desired characteristic not depending on a process variation and an environmental variation. The phase locked loop circuit has a phase frequency comparator, a charge pump, a loop filter, a frequency divider, a selector, and a voltage controlled oscillator. The frequency divider inputs an output signal and a reference signal, divides the output signal, and outputs a feedback signal, and also outputs a select signal, a trimming signal, and a limit signal from the output signal. The voltage controlled oscillator inputs the control voltage, the base voltage, the trimming signal, and the limit signal, changes the output signal frequency according to the control voltage so as to limit the upper limit frequency of the output signal.

Abstract: A conventional method of controlling the passband of a filter involves an increase in cost for a chip due to a large area of a detection circuit for determining the level of an interference wave. The present invention utilizes a result obtained by detecting the amplitude level of a signal with an automatic gain control circuit to appropriately control the passband of a filter. The amplitude level of all the signals including a desired wave and an interference wave is detected by utilizing the automatic gain control circuit to thereby control the passband of a filter on the basis of the result.

Abstract: A logical level converter generates an output signal by which a logical circuit accurately operates even if there is a threshold fluctuation factor. In the logical level converter, an output signal of a voltage control oscillator in a phase locked loop is inputted to a threshold variable inverter. A DC component of another output signal from the threshold variable inverter is inputted to a comparator, and compared with a comparison voltage. A threshold setting signal is outputted on the basis of a comparison result. The threshold value of the threshold variable inverter is changed according to the threshold variable signal, and the output signal is converted into the other output signal. When the comparison result comes to a given state, the value of the threshold setting signal is held, and the other output signal is outputted as a further different output signal.

Abstract: To provide a phase locked loop circuit that is capable of performing an automatic adjustment that satisfies a desired characteristic not depending on a process variation and an environmental variation. The phase locked loop circuit has a phase frequency comparator, a charge pump, a loop filter, a frequency divider, a selector, and a voltage controlled oscillator. The frequency divider inputs an output signal and a reference signal, divides the output signal, and outputs a feedback signal, and also outputs a select signal, a trimming signal, and a limit signal from the output signal. The voltage controlled oscillator inputs the control voltage, the base voltage, the trimming signal, and the limit signal, changes the output signal frequency according to the control voltage so as to limit the upper limit frequency of the output signal.

Abstract: The present invention provides a spread spectrum clock generator that is capable of preventing phase jumps and jitters and suppressing the occurrence of Electro Magnetic Interference components and that can easily be applied to large scale integrated circuits. The spread spectrum clock generator can be configured with a filter, quantizer, fractional divider, and other elements. Also, this clock generator circuitry can be configured by combination of a delta-sigma ?? quantizer and factional divider so that sine wave modulation and random number modulation can be realized. Thereby, control with digital values can be performed. This clock generator prevents precipitous phase variations in the output high frequency clock and makes fine phase control possible. Consequently, EMI reduction by 20-30 dB can be expected.

Abstract: A clock-generating circuit for forming internal clock signals by comparing a signal obtained by delaying, through a variable delay circuit, an input clock signal input through an external terminal with the input clock signal through a phase comparator circuit, and so controlling the delay time of the variable delay circuit that they are brought into agreement with each other, wherein the clock-generating circuit and an internal circuit to be operated by the clock signals formed thereby are formed on a common semiconductor substrate, and an element-forming region in which the clock-generating circuit is formed is electrically isolated from an element-forming region in which the digital circuit is constituted on the semiconductor substrate relying upon the element-isolation technology. The power-source passages, too, are formed independently of other digital circuits.

Abstract: A logical level converter generates an output signal by which a succeeding logical circuit accurately operates even if there is a threshold fluctuation factor. In the logical level converter, an output signal of a voltage control oscillator in a phase locked loop is inputted to a threshold variable inverter. A DC component of another output signal from the threshold variable inverter is inputted to a comparator, and compared with a comparison voltage. A threshold setting signal is outputted on the basis of a comparison result. The threshold value of the threshold variable inverter is changed according to the threshold variable signal, and the output signal is converted into the other output signal. When the comparison result comes to a given state, the value of the threshold setting signal is held, and the other output signal is outputted as a further different output signal.

Abstract: A clock-generating circuit for forming internal clock signals by comparing a signal obtained by delaying, through a variable delay circuit, an input clock signal input through an external terminal with the input clock signal through a phase comparator circuit, and so controlling the delay time of the variable delay circuit that they are brought into agreement with each other, wherein the clock-generating circuit and an internal circuit to be operated by the clock signals formed thereby are formed on a common semiconductor substrate, and an element-forming region in which the clock-generating circuit is formed is electrically isolated from an element-forming region in which the digital circuit is constituted on the semiconductor substrate relying upon the element-isolation technology. The power-source passages, too, are formed independently of other digital circuits.

Abstract: A sensor transmits and receives wireless signals at intervals. A sensor unit, a processor 130, a wireless transmitter circuit, and a wireless receiver circuit are activated in sequence only for a fixed time when the electric power generated by a generator circuit and charged in a capacitor reaches a preset level. Sensing information detected by the sensor unit is processed by the processor circuit and, information on the number of receivable bytes is added to the processing results in the wireless receiver circuit. This added information is sent as sensor information to the wireless host from the wireless transmitting circuit, and the wireless receiver circuit that activated after the wireless transmitter circuit was activated, receives a control information signal from the wireless host. This received information is processed in the processor circuit.

Abstract: A sensor transmits and receives wireless signals at intervals. A sensor unit, a processor 130, a wireless transmitter circuit, and a wireless receiver circuit are activated in sequence only for a fixed time when the electric power generated by a generator circuit and charged in a capacitor reaches a preset level. Sensing information detected by the sensor unit is processed by the processor circuit and, information on the number of receivable bytes is added to the processing results in the wireless receiver circuit. This added information is sent as sensor information to the wireless host from the wireless transmitting circuit, and the wireless receiver circuit that activated after the wireless transmitter circuit was activated, receives a control information signal from the wireless host. This received information is processed in the processor circuit.

Abstract: A communication apparatus includes a phase-locked loop circuit which receives a first signal having a frequency and converts it into an output signal having a transmission frequency and includes a current output type phase comparator which converts a phase difference between the first signal and a second signal into a current signal, a low pass filter which filters the current signal of the current output type phase comparator to produce an output signal a voltage controlled oscillator which produces an output signal having a transmission frequency corresponding to the output signal of the low pass filter the output signal of the voltage controlled oscillator constituting the output signal of the phase-locked loop circuit, a frequency converter which frequency-converts the output signal of the voltage controlled oscillator to produce the second signal, and a current source which supplies a current to an input of the low pass filter.

Abstract: There are provided a transmitter and a wireless communication terminal apparatus using the same for solving a problem of undesired spurs due to harmonics of an output signal of a frequency synthesizer, and further solving a problem of the undesired spurs occurring when the harmonics of an output signal of a crystal oscillator are mixed into a VCO to facilitate to design a circuit or a mounting substrate. The transmitter has a relationship between an output frequency of a PLL frequency conversion circuit (5) and output frequencies of frequency synthesizers (1, 2) stored therein, and the output frequencies of the frequency synthesizers (1, 2) input into the PLL frequency conversion circuit (5) are controlled on the basis of the relationship so that the undesired spurs are suppressed.

Abstract: To provide a phase locked loop circuit that is capable of performing an automatic adjustment that satisfies a desired characteristic not depending on a process variation and an environmental variation. The phase locked loop circuit has a phase frequency comparator, a charge pump, a loop filter, a frequency divider, a selector, and a voltage controlled oscillator. The frequency divider inputs an output signal and a reference signal, divides the output signal, and outputs a feedback signal, and also outputs a select signal, a trimming signal, and a limit signal from the output signal. The voltage controlled oscillator inputs the control voltage, the base voltage, the trimming signal, and the limit signal, changes the output signal frequency according to the control voltage so as to limit the upper limit frequency of the output signal.

Abstract: A logical level converter generates an output signal by which succeeding logical circuit accurately operates even if there is a threshold fluctuation factor. In the logical level converter, an output signal of a voltage control oscillator in a phase locked loop is inputted to a threshold variable inverter. A DC component of another output signal from the threshold variable inverter is inputted to a comparator, and compared with a comparison voltage. A threshold setting signal is outputted on the basis of a comparison result. The threshold value of the threshold variable inverter is changed according to the threshold variable signal, and the output signal is converted into the other output signal. When the comparison result comes to a given state, the value of the threshold setting signal is held, and the other output signal is outputted as a further different output signal.

Abstract: A variable loop bandwidth phase locked loop in which, upon input of a succession of signals “1”, no modulated signal degradation occurs and even at a high symbol rate, the reference signal frequency remains low and the sampling frequencies of a phase-frequency detector and a sigma delta circuit remain low. The phase locked loop comprises: a first modulator which transforms baseband signal TX_DATA into an integer signal for specifying a division number and sends it to a control terminal of a programmable divider; a second modulator which shapes an incoming baseband signal into a prescribed signal waveform and sends it to a voltage controlled oscillator; and a variable current charge pump which changes the loop bandwidth of the phase locked loop according to control signal CUR.

Abstract: The object is simplification of a configuration in a pulse generator for UWB transmission, lower power consumption, and suppression of LO leakage by nonuse of the LO signal.

Abstract: A clock-generating circuit for forming internal clock signals by comparing a signal obtained by delaying, through a variable delay circuit, an input clock signal input through an external terminal with the input clock signal through a phase comparator circuit, and so controlling the delay time of the variable delay circuit that they are brought into agreement with each other, wherein the clock-generating circuit and an internal circuit to be operated by the clock signals formed thereby are formed on a common semiconductor substrate, and an element-forming region in which the clock-generating circuit is formed is electrically isolated from an element-forming region in which the digital circuit is constituted on the semiconductor substrate relying upon the element-isolation technology. The power-source passages, too, are formed independently of other digital circuits.

Abstract: An ultra-wideband transmitter is provided which can reduce a leak of a local signal into a transmitted signal with a pulse train output from an antenna in UWB-IR communication. The transmitter comprises a pulse generator 0140 for generating a pulse signal having a pulse train of pulses produced intermittently according to data to be transmitted, an oscillator 0120 for producing a local signal, a frequency converter 0130 to which the pulse signal output from the pulse generator and the local signal output from the oscillator are input, and for frequency-converting the pulse signal to output a RF signal, an amplifier 0110 for amplifying the RF signal output from the frequency converter, and an antenna 0000 for emitting the RF signal output from the amplifier in the air. In a period corresponding to a pause period of the pulses produced intermittently, a leak of the local signal into the RF signal output from the antenna is reduced using a control signal 0300.

Abstract: A clock-generating circuit for forming internal clock signals by comparing a signal obtained by delaying, through a variable delay circuit, an input clock signal input through an external terminal with the input clock signal through a phase comparator circuit, and so controlling the delay time of the variable delay circuit that they are brought into agreement with each other, wherein the clock-generating circuit and an internal circuit to be operated by the clock signals formed thereby are formed on a common semiconductor substrate, and an element-forming region in which the clock-generating circuit is formed is electrically isolated from an element-forming region in which the digital circuit is constituted on the semiconductor substrate relying upon the element-isolation technology. The power-source passages, too, are formed independently of other digital circuits.