Abstract: A discrete-time analog circuit comprises: a voltage-current conversion circuit that converts an input voltage signal into a current signal and outputs the current signal; and a charge inverting circuit that is connected to an output terminal of the voltage-current conversion circuit to perform charge sharing. The charge inverting circuit includes 2M capacitors (M is an integer greater than or equal to 1) that are provided parallel to each other. In accordance with a predetermined sampling interval, one of the 2M capacitors repeats: (1) sharing input charge that is input by the current signal, (2) holding at least part of the input charge, (3) inverting a polarity of the held charge and connecting to the output terminal to share the held charge, and (4) holding remaining charge. At time period when one of the 2M capacitors is connected to the output terminal, the other capacitor(s) of the 2M capacitors is not connected to either of an input terminal and the output terminal.

Abstract: A discrete-time analog circuit comprises: a voltage-current conversion circuit that converts an input voltage signal into a current signal and outputs the current signal; and a charge inverting circuit that is connected to an output terminal of the voltage-current conversion circuit to perform charge sharing. The charge inverting circuit includes 2M capacitors (M is an integer greater than or equal to 1) that are provided parallel to each other. In accordance with a predetermined sampling interval, one of the 2M capacitors repeats: (1) sharing input charge that is input by the current signal, (2) holding at least part of the input charge, (3) inverting a polarity of the held charge and connecting to the output terminal to share the held charge, and (4) holding remaining charge. At time period when one of the 2M capacitors is connected to the output terminal, the other capacitor(s) of the 2M capacitors is not connected to either of an input terminal and the output terminal.

Abstract: There is provided a variable gain multistage amplifier including: an input terminal to which the input signal is input; multistage amplifiers amplify the input signal, the multistage amplifiers being connected in series; and an output terminal that outputs the amplified signal, and the multistage amplifiers include one or more successive cascode amplifiers, one of which is in final stage.

Abstract: The sampling mixer circuit comprises: a clock generating circuit that outputs four-phase control signals the periods of which are in accordance with the carrier frequency of an input signal and the phases of which are different from one another; a voltage-to-current converting circuit that converts a voltage signal based on the input signal to a current signal; four-system charge sharing circuits in which the current signal as converted is input to a plurality of capacitors in accordance with the different phases based on the four-phase control signals and in which charges are exchanged among the plurality of capacitors; and a phase-to-phase capacitor that is selectively connected, on the basis of the four-phase control signals, to the respective ones of nodes, which are other than the input nodes of the current signal, in the four-system charge sharing circuits.

Abstract: There is provided a variable gain multistage amplifier including: an input terminal to which the input signal is input; multistage amplifiers amplify the input signal, the multistage amplifiers being connected in series; and an output terminal that outputs the amplified signal, and the multistage amplifiers include one or more successive cascode amplifiers, one of which is in final stage.

Abstract: A sampling circuit is provided that includes a first sampling circuit that shifts a frequency, at which a gain of a frequency characteristic is maximized, to a lower frequency side, and a second sampling circuit that shifts the frequency, at which the gain of the frequency characteristic is maximized, to a higher frequency side. The sampling circuit also includes an output section provided in an output side of the first sampling circuit and an output side of the second sampling circuit, and outputs a sum or a difference between an output from the first sampling circuit and an output from the second sampling circuit.

Abstract: The sampling mixer circuit comprises: a clock generating circuit that outputs four-phase control signals the periods of which are in accordance with the carrier frequency of an input signal and the phases of which are different from one another; a voltage-to-current converting circuit that converts a voltage signal based on the input signal to a current signal; four-system charge sharing circuits in which the current signal as converted is input to a plurality of capacitors in accordance with the different phases based on the four-phase control signals and in which charges are exchanged among the plurality of capacitors; and a phase-to-phase capacitor that is selectively connected, on the basis of the four-phase control signals, to the respective ones of nodes, which are other than the input nodes of the current signal, in the four-system charge sharing circuits.

Abstract: The discrete time analog circuit (100) is provided with: a rotate capacitor circuit (150); an amplifier (141) that is connected to the input line or the output line of the rotate capacitor (150), and amplifies the input potential or input charge; a coefficient circuit (140) that is positioned in series with the amplifier (141), and has two history capacitors (143-1, 143-2) positioned parallel to each other; a first active capacitor among the two history capacitors (143-1, 143-2) that is connected to and charges the amplifier (141); and a clock generation circuit (110) that is connected to the input line or the output line without the involvement of the amplifier (141), and that sequentially changes the pairing of the rotate capacitor circuit (150) a second active capacitor, which shares a charge with the rotate capacitor circuit (150).

Abstract: A sampling circuit is provided that includes a first sampling circuit that shifts a frequency, at which a gain of a frequency characteristic is maximized, to a lower frequency side, and a second sampling circuit that shifts the frequency, at which the gain of the frequency characteristic is maximized, to a higher frequency side. The sampling circuit also includes an output section provided in an output side of the first sampling circuit and an output side of the second sampling circuit, and outputs a sum or a difference between an output from the first sampling circuit and an output from the second sampling circuit.

Abstract: A sampling circuit and a receiver are provided having a high flexibility of filter design and excellent characteristics for removing an interfering wave. Provided also are a sampling circuit and a receiver having a low level of the higher harmonic spurious. The sampling circuit includes a charge sampling circuit, which executes sampling of an input signal, and a plurality of charge sharing circuits connected in parallel to the output stage of the charge sampling circuit. The charge sharing circuits include a charge sharing circuit group having transmission functions different from one another, a synthesis circuit, which is arranged at the output side of the charge sharing circuit group and synthesizes the outputs of the charge sharing circuits, and a digital control unit, which outputs a control signal for controlling the operation of the charge sharing circuit group and the synthesis circuit.

Abstract: A sampling circuit and a receiver have a high level of filter design flexibility and excellent image rejection characteristics. Signals with phases that differ by 90° are sampled using an IQ generating circuit and are weighted by each of multiple parallel-connected discrete-time circuits, and the result of addition by an output adding circuit is ultimately output. Alternatively, a configuration in which the multiple parallel-connected discrete-time circuits and the output adding circuit are cascade-connected is adopted, so that frequency characteristics having an attenuation pole to one side can be achieved and excellent image rejection characteristics can be obtained.

Abstract: A sampling circuit and a receiver, with relatively simple configurations, and clocks, exhibiting excellent frequency characteristics, are provided. In discrete time circuits, a charging switch is controlled on and off using one of four-phase control signals. A rotate capacitor shares electrical charge accumulated in an IQ generating circuit via the charging switch. A dump switch is controlled on and off using a different signal from the control signal used to control the charging switch on and off, among the four-phase control signals. A buffer capacitor shares electrical charge with the rotate capacitor via the dump switch to form an output value.

Abstract: The discrete time analog circuit (100) is provided with: a rotate capacitor circuit (150); an amplifier (141) that is connected to the input line or the output line of the rotate capacitor (150), and amplifies the input potential or input charge; a coefficient circuit (140) that is positioned in series with the amplifier (141), and has two history capacitors (143-1, 143-2) positioned parallel to each other; a first active capacitor among the two history capacitors (143-1, 143-2) that is connected to and charges the amplifier (141); and a clock generation circuit (110) that is connected to the input line or the output line without the involvement of the amplifier (141), and that sequentially changes the pairing of the rotate capacitor circuit (150) a second active capacitor, which shares a charge with the rotate capacitor circuit (150).

Abstract: Disclosed is a mixer able to simultaneously suppress self-mixing and low-order harmonic response in a charge sampling circuit. Specifically disclosed is a multiphase mixer provided with a transconductance amplifier (101) for converting a voltage signal into a current signal, an N number (where N is a natural number that is 2 or more) of first integrators (401, 402) which are connected in parallel to the subsequent stage of the transconductance amplifier (101), and a 2N number of mixers (102, 103, 104, 105) connected in parallel in pairs to the respective N number of first integrators (401, 402), wherein two mixers connected to the same first integrator of any of the N number of first integrators (401, 402) are controlled by driving signals comprised of pulse trains with the same frequency and phases differing by 180°.

Abstract: A sampling circuit and a receiver with which filter characteristics compatible with the reception of wideband signals can be realized with a high degree of freedom in the setting of the filter characteristics. More specifically, the sampling circuit is capable of removing adjacent interfering wave signals while keeping in-band deviation small. The sampling circuit is equipped with a discrete-time analog processing circuit group, wherein multiple discrete-time analog processing circuits are connected in parallel, a synthesizer that synthesizes the output signals from each of the circuit systems and outputs same, and a digital control unit that outputs control signals. Each of the discrete-time analog processing circuits is configured to include multiple rotate capacitor units, which each includes a main rotate capacitor and a sub-rotate capacitor, and only the main rotate capacitors share electric charge with a buffer capacitor included in the synthesizer.

Abstract: A direct sampling circuit and a receiver which carry out discrete time analog processing with a high degree of design freedom and are provided with a filter property which is achievable to comply with the receipt of a broad band signal. A plurality of discrete time analog processing circuits (101) are connected in parallel with each other, a gm value and a capacitance of a capacitor in each circuit system are set independently based on a prescribed condition, and an output signal obtained from each circuit system is synthesized by means of a buffer capacitor (102), so that an equivalently high-dimensional IIR filter can be put into practice.

Abstract: Disclosed is a mixer able to simultaneously suppress self-mixing and low-order harmonic response in a charge sampling circuit. Specifically disclosed is a multiphase mixer provided with a transconductance amplifier (101) for converting a voltage signal into a current signal, an N number (where N is a natural number that is 2 or more) of first integrators (401, 402) which are connected in parallel to the subsequent stage of the transconductance amplifier (101), and a 2N number of mixers (102, 103, 104, 105) connected in parallel in pairs to the respective N number of first integrators (401, 402), wherein two mixers connected to the same first integrator of any of the N number of first integrators (401, 402) are controlled by driving signals comprised of pulse trains with the same frequency and phases differing by 180°.

Abstract: A sampling circuit and a receiver with relatively simple configuration and clocks, exhibiting excellent frequency characteristics, are provided. In discrete time circuits (102-1 to 102-4), charging switch (1021) is controlled on and off using one of four-phase control signals. Rotate capacitor (1022) shares electrical charge accumulated in IQ generating circuit (101) via charging switch (1021). Dump switch (1023) is controlled on and off using a different signal from the control signal used to control charging switch (1021) on and off, among the four-phase control signals. Buffer capacitor (1026) shares electrical charge with rotate capacitor (1022) via dump switch (1023) to form an output value.

Abstract: Disclosed are a sampling circuit and a receiver having a high flexibility of the filter design and excellent characteristics for removing an interfering wave. Provided also are a sampling circuit and a receiver having a low level of the higher harmonic spurious. The sampling circuit (100) includes: a charge sampling circuit (101) which executes sampling of an input signal; and a plurality of charge sharing circuits (102-1 to 102-N) connected in parallel to the output stage of the charge sampling circuit (101). The charge sharing circuits (102-1 to 102-N) includes: a charge sharing circuit group (102) having transmission functions different from one another; a synthesis circuit (103) which is arranged at the output side of the charge sharing circuit group (102) and synthesizes the outputs of the charge sharing circuits (102-1 to 102-N); and a digital control unit (104) which outputs a control signal for controlling the operation of the charge sharing circuit group (102) and the synthesis circuit (103).

Abstract: Disclosed are a sampling circuit and a receiver that have a high level of filter design flexibility and excellent image rejection characteristics. Signals with phases that differ by 90° are sampled using an IQ generating circuit (101) and are weighted by each of multiple parallel-connected discrete-time circuits (102-1-102-n), and the result of addition by an output adding circuit (103) is ultimately output. Alternatively, a configuration in which the multiple parallel-connected discrete-time circuits (102-1-102-n) and the output adding circuit (103) are cascade-connected is adopted, so that frequency characteristics having an attenuation pole to one side can be achieved and excellent image rejection characteristics can be obtained.