Patent application number | Description | Published |
20080204298 | AD CONVERTER AND RADIO RECEIVER - Disclosed is an AD converter including: a first conversion stage including a quantizing part to generate m parallel pieces of quantized signals from m pieces of input analog signals representing n-dimensional vectors (n≦m≦2n), a decoding part to generate m pieces of decoded analog signals from the m parallel pieces of quantized signals, and a residual amplifying part to output m pieces of amplified residual signals by multiplying respective differences between each of the m pieces of analog signals and each of the m pieces of decoded analog signals; a second conversion stage including a quantizing part to generate m parallel pieces of quantized signals from the m pieces of amplified residual signals; and a synthesizing part to generate m parallel pieces of digital signals by synthesizing each of the quantized signals in the first conversion stage and in the second conversion stage at each parallel position. | 08-28-2008 |
20080242253 | Frequency converter and radio receiver using the same - According to an embodiment of the invention, there is provided a frequency converter including: an input circuit converting a voltage signal to a current signal; a load circuit supplying a constant current to an input circuit; a first switch circuit configured to output a current signal from the first output terminal in accordance with a switching made in accordance with a first oscillation signal; a second switch circuit configured to output the current signal from the second output terminal in accordance with a switching made in accordance with a second oscillation signal being 180 degrees out of phase with the first oscillation signal; a control circuit generating a control current based on a predetermined reference voltage and an average voltage of the voltages at the first and second output terminals and adding the control current to the current signal of the input circuit. | 10-02-2008 |
20080274714 | AMPLIFIER, FILTER USING THE SAME, AND RADIO COMMUNICATION DEVICE - An amplifier includes an amplification unit which amplify a first difference between first and second input signals, a second difference between second and third input signals and a third difference between third and first input signals by a differential mode gain, and amplify an average of the first, second and third input signal by a common mode gain, for outputting a first output signal corresponding to a sum of the amplified first difference and the amplified average, a second output signal corresponding to a sum of the amplified second difference and the amplified average, and a third output signal corresponding to a sum of the amplified third difference and amplified average; first, second; and a reduction circuit which reduces the common mode gain less than the differential mode gain. | 11-06-2008 |
20080291070 | DIGITAL/ANALOG CONVERTER AND TRANSMITTER - According to an embodiment of the invention, there is provided a digital/analog converter includes: a decoder that converts a (n−1)-phase input digital signal to a n-phase output digital signal; and a signal generating unit that generates analog signals according to the n-phase output digital signal. | 11-27-2008 |
20080309436 | MULTI-INPUT MULTI-OUTPUT AMPLIFIER, AN ACTIVE INDUCTOR, A FILTER AND A RADIO COMMUNICATION DEVICE - A non-inverting amplifier includes n external input terminals which receive n (n≧3) input voltage signals having a constant sum of voltages, respectively, n amplification units each including n−1 internal input terminals connected to n−1 terminals of the n external input terminals in a different combination for each of the amplification units, n−1 voltage-to-current converters which convert input voltage signals from the internal input terminals into current signals, and a load which converts an added current signal obtained by adding up the current signals into an output voltage signal, and n external output terminals which output n output voltage signals from the n amplification units. | 12-18-2008 |
20090033427 | OSCILLATOR, PLL OSCILLATOR, RADIO APPARATUS - An oscillator includes a plurality of oscillating units connected in parallel with each other, and a control unit which controls the number of parallel connections of the plurality of oscillating units based on an instruction signal indicating accuracy to be tolerated with respect to oscillation outputs of the oscillating units. | 02-05-2009 |
20090079598 | SAMPLE RATE CONVERTER - The sample rate converter includes a synthesizing unit which synthesizes an input signal sampled with frequency fs with a feedback signal of the frequency fs, in a frequency band from 0 to fs/N (where N indicates a natural number), with a gain greater than at least 1, to generate a synthesized signal, a downsampler which downsamples the synthesized signal to obtain an output signal of sample rate fs/N, and an upsampler which upsamples the output signal to generate the feedback signal. | 03-26-2009 |
20090184857 | A/D CONVERTING APPARATUS - An A/D converting apparatus includes a first A/D converter to sample an analog input signal having a D/A converter to generate a comparative signal for successive comparison with the analog input signal, a signal generator generate a differential signal between the analog input signal and the comparative signal, and a comparator to compare the comparative signal with a standard value to generate a first digital signal exhibiting high-order bit; an amplifier to amplify the differential signal to generate a residue signal; and a second A/D converter to sample the residue signal to generate a second digital signal exhibiting low-order bit. | 07-23-2009 |
20090245418 | TRANSMITTER USING CARTESIAN LOOP - A transmitter includes a signal generator to generate a digital baseband signal corresponding to a signal to be transmitted, a digital-analog converter to convert the digital baseband signal into an analog baseband signal by operating in accordance with a clock signal, a subtracter to subtract a feedback baseband signal from the analog baseband signal to generate a residual signal, a loop filter to filter the residual signal by amplifying a low-frequency component and suppressing a high-frequency component, a modulator to modulate the filtered signal by multiplying the filtered signal, a power amplifier to amplify the modulated signal, a high frequency filter to filter the amplified modulated signal to obtain a transmit RF signal, the high frequency filter having a passband width narrower than a frequency of the clock signal, and a demodulator to demodulate a feedback RF signal which is divided from the transmit RF signal. | 10-01-2009 |
20090245429 | SAMPLE RATE CONVERTER AND RECEIVER USING THE SAME - A sample rate converter includes a multiplexer which multiplexes input signals, an interpolator which interpolates a multiplexed output signal to generate a first feedback signal, a multiplier which multiplies the first feedback signal by a coefficient, a subtracter which subtracts the multiplied signal from the multiplexed input signal, an adder which adds the residual signal and a second feedback signal to sequentially generate integrated signals corresponding to the input signals, respectively, a register circuit configured to individually hold integrated signals, a multiplexer which multiplexes the integrated signals from the register circuit to generate the second feedback signal, a multiplexer which multiplexes the integrated signals from the register circuit to generate a decimation target signal, a decimator which subjects the decimation target signal to decimation to generate the multiplexed output signal, and a discrimination circuit configured to discriminate the multiplexed output signal to generate output signals. | 10-01-2009 |
20090245437 | SAMPLE RATE CONVERTER AND RCEIVER USING THE SAME - A sample rate converter includes a multiplexer to select either one of an input signal and a first feedback signal, and to obtain a selected input signal, a decimator performing decimation on an Nth-order integration signal to generate an output signal, an interpolator performing interpolation on the output signal to generate a second feedback signal, a multiplier which multiplies the second feedback signal by a coefficient to generate a multiplication signal, a subtractor which subtracts the multiplication signal from the selected input signal to generate a residual signal, an adder which adds the residual signal to a third feedback signal to sequentially generate 1st-order to Nth-order integration signals, a register circuit configured to hold the integration signals, a multiplexer to select the first feedback signal from the integration signals that the register hold, and a multiplexer to select the third feedback signal from the integration signals that the register hold. | 10-01-2009 |
20100112971 | FREQUENCY CONVERTING CIRCUIT AND RECEIVER - A receiver includes a multiphase mixer that multiplies a received radio signal by multiphase local signals the number of which is the same as an integer having a first prime factor and a second prime factor different from the first prime factor, and generates first multiphase baseband signals the number of which is the same as the integer, a first processing circuit that suppresses common modes for first multiphase signal groups formed by dividing the first multiphase baseband signals into groups of signals the number of which is the same as the first prime factor, and generates second multiphase baseband signals, and a second processing circuit that suppresses common modes for second multiphase signal groups formed by dividing the second multiphase baseband signals into groups of signals the number of which is the same as the second prime factor, and generates third multiphase baseband signals. | 05-06-2010 |
20100150270 | SIGNAL PROCESSING CIRCUIT AND RECEIVER USING THE SAME - A signal processing circuit includes a decimation filter which down-samples over-sampled first three-phase digital signals to obtain second three-phase digital signals, and a converter which subjects the second three-phase digital signals to a three-phase to IQ conversion, and obtains orthogonal digital signals. | 06-17-2010 |
20100151800 | COMMUNICATION DEVICE AND COMMUNICATION METHOD - A communication device includes: a first oscillator to generate a local signal based on a control signal for regulating at least one of phase oise and jitter in the local signal; a frequency converter to convert a first signal having first frequency to a second signal having second frequency by using the local signal; a filter to remove undesired signal component from the second signal and output a third signal; and a controller to generate the control signal based on the second signal and the third signal. | 06-17-2010 |
20100233986 | RECEIVER - A receiver includes a high-frequency filter which extracts, from a radio signal, a high-frequency signal, a first frequency converter which performs frequency conversion on the high-frequency signal using a first local signal, to obtain a first baseband signal, a second frequency converter which performs frequency conversion on the high-frequency signal using a second local signal, to obtain a second baseband signal, the second local signal having a frequency equal to an integral multiple of a frequency of the first local signal, and a subtraction processing unit configured to multiply the second baseband signal by a control coefficient for amplitude adjustment to obtain a product signal, and subtract the product signal from the first baseband signal to obtain a residual signal. | 09-16-2010 |
20130076544 | ANALOGUE TO DIGITAL CONVERTER AND SIGNAL PROCESSING SYSTEM - According to one embodiment, an analogue to digital converter converts an analogue input signal to a digital output signal. The converter includes an analogue to digital converting unit, a multiplexer, a pseudo-alias signal generator, a gain controller, and an alias signal compensator. The analogue to digital converting unit converts the analogue input signal to a plurality of digital signals. The multiplexer sequentially selects one of the digital signals and outputs the selected digital signal as a multiplexer output. The pseudo-alias signal generator generates a plurality of pseudo-alias signals from the digital signals. The pseudo-alias signal simulates an alias signal component in the multiplexer output. The gain controller generates a plurality of gain control signals by using the pseudo-alias signals. The gain control signal controls gain of the digital output signal. The alias signal compensator compensates the alias signal component by using the gain control signals. | 03-28-2013 |
20130076545 | TIME ERROR ESTIMATING DEVICE, ERROR CORRECTION DEVICE AND A/D CONVERTER - A time error estimating device for estimating a sampling time error of each of a plurality of sampling circuits when the sampling circuits generates a plurality of sampling output signals by performing sampling at timings shifted from one another has correlators each configured to obtain a correlation value representing a similarity between the sampling output signals, and a weight adder configured to estimate the sampling time error of the sampling circuits, based on a result obtained by adjusting a weight on the correlation value. | 03-28-2013 |
20150055726 | FRACTIONAL FREQUENCY DIVIDING CIRCUIT AND TRANSMITTER - According to one embodiment, there is provided a fractional frequency dividing circuit including an integral frequency dividing circuit and an adjustment circuit. The integral frequency dividing circuit is configured to convert a reference signal to K (K is a positive integer) phase signals. Each of the K phase signals has a frequency of one nth (n is a positive integer) of the reference signal and has different phases from each other. The adjustment circuit is configured to weighting-add a plurality of signals corresponding to the K phase signals and generate a fractional-frequency-divided signal. The fractional-frequency-divided signal has a frequency of m times (m is a positive integer that is not multiplies of n) of each of the plurality of phase signals. | 02-26-2015 |