Patent application number | Description | Published |
20090021312 | PLL circuit - It has been difficult that conventional PLL circuits have a suppression characteristic of suppressing the phase noise which is free of variation due to temperature and individual difference and stable in a wide frequency band. The present invention provides a PLL circuit which can absorb variation of phase noise characteristic due to temperature and individual difference and has a phase noise suppression characteristic stable in a wide frequency band. The PLL circuit comprises, at the succeeding stage, a first register for storing a first parameter for controlling the loop gain, a first multiplier for multiplying the output of the phase comparator by a first parameter, a second register for storing a second parameter for controlling the response characteristic, a second multiplier for multiplying the output of the first multiplier by a second parameter, and a CPU for setting optimum parameters in the first and second registers depending on the use frequency band, the ambient temperature, and the device individual difference. By controlling the loop gain and the response characteristic to optimum values, a good suppression characteristic in a wide frequency band is achieved. | 01-22-2009 |
20090039973 | VCO driving circuit and frequency synthesizer - A VCO driving circuit and a frequency synthesizer wherein the impedance viewed from a VCO control terminal is reduced to prevent the VCO phase noise characteristic from degrading. A VCO driving circuit and a frequency synthesizer having the VCO driving circuit, which comprises a coarse adjustment DAC that receives a digital data, which has a coarse adjustment frequency, to output an analog signal; a fine adjustment DAC that receives a digital data, which has a fine adjustment frequency, to output an analog signal; a low response speed LPF | 02-12-2009 |
20090072947 | Control method for high-frequency radio equipment and high-frequency radio system - A control method for a high-frequency radio equipment and a high-frequency radio equipment system in spread spectrum radio data communication are provided which are interference-tolerant and can maintain transmission quality with improved receiving sensitivity. | 03-19-2009 |
20090134946 | Oscillation frequency control circuit - Provided is an oscillation frequency control circuit, which corrects its own frequency so that it can hold an oscillation frequency stably even when it does not have an input of a highly stable reference signal but makes a self-run. The oscillation frequency control circuit comprises a voltage-controlled oscillator, a frequency divider, a phase comparator, a loop filter, a detecting circuit for detecting an external reference signal, a PWM circuit for generating pulses, when pulse generating information inputs, to output the pulses to the loop filter, a memory for storing the pulse generating information corresponding to voltage information, a switch for turning ON/OFF the connection between the phase comparator and the loop filter, and a CPU for turning ON the switch, if the level of the external reference signal detected by the detecting circuit is within a proper range, but OFF the switch, if the level is outside of the proper range, thereby to output the pulse generating information stored in the memory, to the PWM circuit. | 05-28-2009 |
20100264961 | Oscillation frequency control circuit - Provided is an oscillation frequency control circuit for correcting its frequency, keeping the oscillation frequency stable when self-oscillating, and oscillating with a control voltage generated by making a fixed voltage given from outside variable. In the oscillation frequency control circuit, a CPU selects/outputs the control voltage preferentially according to a command of a control voltage selection. If the command is not given and the level of an outside reference signal detected by a detecting circuit is within an adequate range, it turns a select switch on. If the command is not given and the level of the outside reference signal is out of the adequate range, it turns the select switch off and outputs information about pulse generation stored in a memory to a PWM circuit. | 10-21-2010 |
20100264962 | VCO DRIVING CIRCUIT AND FREQUENCY SYNTHESIZER - A VCO driving circuit and a frequency synthesizer wherein the impedance viewed from a VCO control terminal is reduced to prevent the VCO phase noise characteristic from degrading. A VCO driving circuit and a frequency synthesizer having the VCO driving circuit, which comprises a coarse adjustment DAC that receives a digital data, which has a coarse adjustment frequency, to output an analog signal; a fine adjustment DAC that receives a digital data, which has a fine adjustment frequency, to output an analog signal; a low response speed LPF | 10-21-2010 |
20110032005 | Frequency synthesizer - A frequency synthesizer in which a satisfactory frequency stability can be obtained over the entire long period of service immediately after power activation is disclosed. The reference signal generation circuit includes an OCXO, a TCXO, weight converters which regulate weights with respect to outputs, and an adder which adds up the outputs from the weight converters to output the added output as a reference signal. The CPU controls weight converters B and C so that the weight of the TCXO is set to 100% and the weight of the OCXO is set to 0% at the time of the power activation, so that the weight of the OCXO gradually rises, and so that the weight of the TCXO is set to 0% and the weight of the OCXO is set to 100% after preset time, whereby the frequency can quickly be stabilized after the power activation. | 02-10-2011 |
20110204935 | PLL circuit - Provided is a PLL circuit improving reliability while suppressing power consumption without degrading noise characteristics. The PLL circuit includes a PLL IC that divides an output frequency Fout from a VCO, compares phase with a reference signal, and feeds back a phase difference as a control voltage to the VCO. A control circuit is capable of finely setting both of a reference frequency Fref and an output frequency Fdds in a DDS circuit, and the DDS circuit generates folding signals of Fdds for Fref and an integral multiple frequency thereof based on the combination of the frequencies. A first AMP amplifies a signal, a variable filter selects a desired Fdds (desired) and a second AMP amplifies the signal and supplies the same to the PLL IC as a reference signal. The control circuit further supplies a division ratio N to the PLL IC. | 08-25-2011 |
Patent application number | Description | Published |
20100013393 | DISCHARGE LAMP LIGHTING DEVICE, AND ILLUMINATING DEVICE - In order to enhance stability of a discharge lamp at the time of dimming lighting even in the case where a light output is lowered, a direct current superimposing circuit superimposes a direct current voltage on an alternating current voltage applied to a fluorescent lamp, and a dimming signal correction circuit receives a detection value of a direct current voltage detection circuit and a dimming signal that is from an outside, outputs a dimming signal higher in level than the dimming signal in the case where the detection value of the direct current voltage detection circuit exceeds a first threshold value, and decreases the level of the outputted dimming signal to the level of the inputted dimming signal in the case where the detection value of the direct current voltage detection circuit falls down below a second threshold value that is equal to or less than the first threshold value. Then, an amount of alternating current power supplied to the fluorescent lamp by an inverter circuit is increased and decreased in response to fluctuations of the level of the dimming signal outputted by the dimming signal correction circuit, whereby the fluorescent lamp is dimmed. | 01-21-2010 |
20100270932 | FAULT DETECTION AND SHUTDOWN CONTROL CIRCUITS AND METHODS FOR ELECTRONIC BALLASTS - An electronic ballast is capable of inhibiting ballast shutdown caused by erroneously determining a fault condition. The ballast includes a DC power supply circuit for outputting DC power, a power conversion circuit that appropriately converts DC power outputted by the DC power supply circuit and outputs it to a discharge lamp, a DC voltage droop detection circuit for determining existence/absence of a fault condition in the DC power supply circuit | 10-28-2010 |
20100270949 | ELECTRONIC BALLAST WITH INPUT VOLTAGE FAULT CONTROL - An electronic ballast includes circuitry to prevent a switch from being damaged in the case where an abnormality occurs in an output voltage of an input power supply. A DC power supply control circuit has a zero current detection circuit that, when a current through an inductor becomes equal to or less than a predetermined current value, outputs a zero signal. A peak current detection circuit, when current through a switch the DC power supply circuit becomes equal to or greater than the predetermined current value, outputs a peak signal. A first drive circuit turns on the switch according to the zero signal, and turns off the switch Q | 10-28-2010 |
Patent application number | Description | Published |
20090146742 | PLL Apparatus - It is an object of the present invention to provide a PLL apparatus outputting a frequency signal from a voltage-controlled oscillation unit in synchronization with an external reference frequency signal, in which the fluctuation of the frequency is reduced even when the external reference signal has a trouble. | 06-11-2009 |
20090167382 | PLL Apparatus - It is an object of the present invention to provide a PLL apparatus realizing extremely high frequency stability. | 07-02-2009 |
20090273335 | Sensing instrument - In adopting a structure in which an oscillator circuit unit and an instrument main body including a measuring unit are separately formed in a sensing instrument measuring the concentration of or determining the presence/absence of a substance to be sensed by using a quartz sensor, the present invention has an object to enable the instrument main body side to know an oscillation frequency of the connected oscillator circuit unit. | 11-05-2009 |
20090308142 | Sensing instrument - In a sensing instrument using a quartz sensor on whose front surface an adsorption layer for adsorbing a substance to be sensed is formed and which changes in natural frequency by the adsorption of the substance to be sensed, the present invention has an object to quickly detect a trouble of the quartz sensor to prevent an operator from recognizing an incorrect measurement result. | 12-17-2009 |
20140077844 | SIGNAL LEVEL ADJUSTING DEVICE AND HIGH-FREQUENCY APPARATUS - To provide, in a frequency synthesizer including: a variable attenuator provided at a subsequent stage of a voltage controlled oscillator; a detector; and a control unit outputting a control voltage for adjusting an attenuation amount of the variable attenuator via a digital/analog converter in accordance with a detection voltage, a technology with which a spurious due to a change in an output of the digital/analog converter can be suppressed. A low-pass filter is provided between an output side of a digital/analog converter and a variable attenuator to cut a frequency component corresponding to an overshoot generated when an output of the digital/analog converter is changed. Further, a period of time from when a control unit outputs a control voltage to when it reads a signal level detected by a detector is set to a period of time longer than a time constant of the low-pass filter determined by a cut-off frequency of the low-pass filter so that no influence is exerted on an operation of automatically controlling the signal level. | 03-20-2014 |
20140210566 | CRYSTAL RESONATOR, CRYSTAL RESONATOR PACKAGE, AND CRYSTAL OSCILLATOR - A crystal resonator includes a crystal element and excitation electrodes. The crystal element includes an α crystal region and a β crystal region that have mutually different positive/negative directions along an X-axis. Each two or more of the α crystal regions and the β crystal regions are alternately formed along a direction perpendicular to the X-axis. The excitation electrodes are formed on both surfaces of the respective α crystal region and β crystal region other than crystal regions positioned at both end portions of a row of the α crystal regions and the β crystal regions. | 07-31-2014 |