Abstract: 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.

Abstract: 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 genera

Abstract: 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.

Abstract: 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.

Abstract: An A/D converter which converts an analog current signal into a digital signal, includes: a filter removing a noise component from the analog current signal to output an analog voltage signal; a quantizer quantizing the analog voltage signal outputted from the filter to generate the digital signal; and a D/A converter converting the digital signal generated by the quantizer into an analog feedback current to feedback to an input of the filter, and supplying a bias current for the D/A converter to an output of a frequency converter via a path of the analog current signal as a bias current driving the frequency converter outputting the analog current signal.

Abstract: 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.

Abstract: 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.

Abstract: A D/A converter includes a plurality of current sources configured to be on or off according to input digital data; a constant voltage source configured to apply a constant voltage to the current sources; current supply wirings provided between the constant voltage source and the respective current source, the current supply wirings respectively having equal length from the constant voltage source to the respective current source; ground-side wirings summing up output currents from the plurality of current sources; and output terminals connected to the ground-side wirings, the output terminals outputting analogue data corresponding to the input digital data.

Abstract: A multiplier includes a first input terminal which receives a modulated signal, three second input terminals which receive first, second, and third local signals respectively, the first, second, and third local signals having a phase difference of 120° from one another, a multiplication unit configured to multiply the modulated signal by each of the first, second, and third local signals, and output first, second, and third multiplied output signals, and three output terminals from which the first, second, and third multiplied output signals are derived, respectively.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An A/D converter which converts an analog current signal into a digital signal, includes: a filter removing a noise component from the analog current signal to output an analog voltage signal; a quantizer quantizing the analog voltage signal outputted from the filter to generate the digital signal; and a D/A converter converting the digital signal generated by the quantizer into an analog feedback current to feedback to an input of the filter, and supplying a bias current for the D/A converter to an output of a frequency converter via a path of the analog current signal as a bias current driving the frequency converter outputting the analog current signal.

Abstract: 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.

Abstract: An A/D converter which converts an analog current signal into a digital signal, includes: a filter removing a noise component from the analog current signal to output an analog voltage signal; a quantizer quantizing the analog voltage signal outputted from the filter to generate the digital signal; and a D/A converter converting the digital signal generated by the quantizer into an analog feedback current to feedback to an input of the filter, and supplying a bias current for the D/A converter to an output of a frequency converter via a path of the analog current signal as a bias current driving the frequency converter outputting the analog current signal.

Abstract: 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.