Abstract: An ultrafast sampler includes a series of Schottky diodes configured with a coplanar waveguide to form a nonlinear transmission line (NLTL) that compresses a local oscillator input to form a series of strobe pulses. Strobe pulses of opposite polarity are capacitively coupled to sampling diodes to obtain samples of a signal applied to a signal input. The samples are directed along an intermediate frequency waveguide to, for example, a signal processor such as an oscilloscope, for storage and analysis. The intermediate frequency waveguide is configured so that conductors of the intermediate frequency waveguide receive signal samples of a common polarity and strobe samples of opposite polarities so that portions of strobe pulses delivered to a signal processor are distinguished from signal samples.

Abstract: A bipolar pulse generator circuit generates bipolar pulses and provides an impedance transformation. The circuit is amenable for implementation in a variety of configurations depending on the size and pulse width requirements for the design. It also maximizes energy transfer and may be implemented in a straight forward, easy manner. The generator may be implemented with one or two switches in a three, five or more transmission line implementation and may include inductive stub, which is inherent element of transmission line transformers. The generator may also be implemented in a multi-layer folded configuration, with or without the addition of a ground potential conductor. The generator may also be implemented in stacked or/and balanced configurations.

Abstract: A system and method for recovering a high frequency component of a slew rate controlled signal propagating along a transmission line enables the high frequency component to be recovered after being lost because of slew rate control and transmission line low pass filtering effects. The system includes a wave shaping circuit for receiving and shaping the slew rate controlled signal to recover the high frequency component. The method includes receiving the slew rate controlled signal, and recovering the high frequency component by shaping the slew rate controlled signal to produce a shaped signal, where the shaped signal includes the received slew rate controlled signal and the high frequency component.

Abstract: A system for propagating a non-dispersive signals includes a transmission line with a voltage dependent propagation constant and distributed gain elements to maintain the non-dispersive signal between a maximum propagating amplitude and a minimum propagating amplitude.

Abstract: An evaluation board having an interconnection line pattern formed thereon is disclosed. The interconnection line pattern has a first end to be connected to a cable assembly and a second end to be connected to a measurement device measuring the transmission characteristic of the cable assembly. The evaluation board includes an equalizer circuit equalizing the transmission characteristic of the cable assembly.

Abstract: Conductor segments are positioned within a transmission line structure in order to generate microwave pulses. The conductor segments are switchably coupled to one or the other of the transmission lines or to each other, in parallel with the transmission line structure. Microwave pulses will be induced in the transmission line by closing the switches in a controlled manner to discharge successive segments or successive groups of segments into the transmission lines. The induced waves travel uninterrupted along the transmission lines in a desired direction.

Abstract: A microwave pulse compressor has an elongated, cross-sectionally oversized waveguide resonator for decreasing the attenuation of the resonator, thereby increasing the resonator's QO The increased Q of the resonator guide results in more stored energy and greater output pulse power. The pulse compressor is constructed to suppress high order modes that can be generated in oversized waveguides. The higher order modes are suppressed by any means, including, separately or in combination, the input coupling design, choice of the resonator length, and the design of the output coupling structures. In one alternative aspect of the invention, the switch at the switch-out end of the waveguide resonator is a plasma switch, employing at least one dielectric window positioned in the resonator guide to have minimum effect on the resonator Q. The dielectric window contains a relatively large volume of a switch gas at low pressure within a switching section of the resonator guide at the guide's switch-out end.

Abstract: An apparatus for propagating a non-dispersive signals includes a transmission line with a voltage dependent propagation constant and distributed gain elements to maintain the non-dispersive signal between a maximum propagating amplitude and a minimum propagating amplitude.

Abstract: Conductor segments are positioned within a transmission line structure in order to generate microwave pulses. The conductor segments are switchably coupled to one or the other of the transmission lines or to each other, in parallel with the transmission line structure. Microwave pulses will be induced in the transmission line by closing the switches in a controlled manner to discharge successive segments or successive groups of segments into the transmission lines. The induced waves travel uninterrupted along the transmission lines in a desired direction.

Abstract: The present invention is directed to a noise suppressor for electronic signals. The noise suppressor at least includes Aluminum Oxide (Al2O3) that is sintered under high temperature, resulting in ceramic Aluminum Oxide (Al2O3) for effectively absorbing or suppressing noise, and reshaping the waveform or filtering waveform glitch of the electronic signals.

Abstract: A non-linear waveguide comprises a transmission line including a first conductive line and a second conductive line; a first bias voltage supply connected with the transmission line; and one or more pairs of diodes connected between the first conductive line and the second conductive line, the one or more pairs of diodes including: a first diode having an anode connected with the first conductive line and a cathode connected with the second conductive line; a second diode having a cathode connected with the first conductive line and an anode connected with the second conductive line; and a second bias voltage supply connected between the anode of the second diode and the second conductive line.

Abstract: A bipolar pulse generator circuit generates bipolar pulses and provides an impedance transformation. The circuit is amenable for implementation in a variety of configurations depending on the size and pulse width requirements for the design. It also maximizes energy transfer and may be implemented in a straight forward, easy manner. The generator may be implemented with one or two switches in a three, five or more transmission line implementation and may include inductive stub, which is inherent element of transmission line transformers. The generator may also be implemented in a multi-layer folded configuration, with or without the addition of a ground potential conductor. The generator may also be implemented in stacked or/and balanced configurations.

Abstract: Systems and methods are described for transmitting a waveform having a controllable attenuation and propagation velocity. An exemplary method comprises: generating an exponential waveform, the exponential waveform (a) being characterized by the equation Vin=De?ASD[x?vSDt], where D is a magnitude, Vin is a voltage, t is time, ASD is an attenuation coefficient, and vSD is a propagation velocity; and (b) being truncated at a maximum value. An exemplary apparatus comprises: an exponential waveform generator; an input recorder coupled to an output of the exponential waveform generator; a transmission line under test coupled to the output of the exponential waveform generator; an output recorder coupled to the transmission line under test; an additional transmission line coupled to the transmission line under test; and a termination impedance coupled to the additional transmission line and to a ground.

Abstract: Conductor segments are positioned within a two conductor transmission line in order to generate microwave pulses. The conductor segments are switchably coupled to one or the other of the transmission lines in parallel. Microwave pulses may be induced in the transmission line by closing the switches in a controlled manner to discharge successive segments into the transmission lines. The induced waves travel uninterrupted along the transmission lines in a desired direction.

Abstract: A pulse generating circuit and related method, for producing extremely narrow pulses for use in monolithic microwave integrated circuits (MMICs) for radar, high-speed sampling, pulse radio and other applications. A sinusoidal input signal is supplied to two nonlinear shock wave generators, which are oppositely biased to produce periodic outputs that are mirror images of each other, one with a very steep rising edge and one with a very steep falling edge. The combined outputs would cancel each other completely but for the introduction of a slight time delay in one of them, which results in a narrow peak in the combined signals.

Abstract: Comb generators include a nonlinear transmission line (NLTL) having one or more NLTL sections. Each NLTL section includes one or more nonlinear elements and transmission line portions that provide transmission line dispersion. Typically, the nonlinear elements are Schottky diodes, and a pulse forming bias network is configured to establish Schottky diode bias conditions using a periodic signal that is input to the comb generator. For input periodic signals at frequencies between about 500 MHz and 1 GHz, output signals are produced having substantial power in frequency components at frequencies up to at least about 50 GHz.

Abstract: Conductor segments are positioned within a two conductor transmission line in order to generate microwave pulses. The conductor segments are switchably coupled to one or the other of the transmission lines in parallel. Microwave pulses may be induced in the transmission line by closing the switches in a controlled manner to discharge successive segments into the transmission lines. The induced waves travel uninterrupted along the transmission lines in a desired direction.

Abstract: A filter circuit includes a signal source, an inductor, a load, and a compensator. The inductor and the load are connected between two terminals of the signal source in series. The compensator is connected in parallel with the inductor.

Abstract: Microwave generator having two electrodes which are provided in a housing and are separated via a spark gap which breaks down when a high voltage is applied in order to emit microwaves, in which the first electrode (6) is in the form of a pot, and the other, inner electrode (5) engages over the first electrode on the outside at a distance therefrom at least over a part of the length thereof with the pot-shaped electrode (6) having a bottom section (10) which concurrently forms the side termination of the housing.

Abstract: A comb frequency generator that is tunable to vary the width of the pulses in the output signal and achieve a maximum power output at different harmonic frequencies. A wavefront compression device receives a sinusoidal input signal and provides wavefront compression to create a compressed signal having a series of periodic fast edges. A delay device receives the fast-edge compressed signal and delays the fast-edge signal to create a delayed fast-edge signal. A combining device receives the original fast-edge compressed signal and the delayed fast-edge compressed signal to generate an output signal including a series of pulses having a width determined by the delay of the delayed signal. In one embodiment, the delay device is a shorted transmission line stub having a length selectively set by a series of MEM devices. In another embodiment, the delay device is an NLTL variable time delay device that delays the fast-edge signal.

Abstract: An ultrafast sampling system includes an interposer and a sampler that include series of Schottky diodes configured with a non-parallel waveguide to form shocklines or nonlinear transmission line (NLTLs) that produce a differential strobe pulse. The shocklines are defined by non-parallel conductors that are configured as, for example, triangular, dentate, arcuate, or other shapes, or as conductors that have edges that are triangular, dentate, arcuate, or the like. The conductors are defined with respect to a substrate, and are airbridged so that at least some portions of the conductors are displaced from the substrate to reduce waveguide capacitance. Electrical connection to the sampler is made with airline having a inner conductor that is deformable to contact an input pad defined on the sampler.

Abstract: A left-handed nonlinear transmission line system has multiple nonlinear capacitors connected in series between input and output terminals and multiple inductances connected in parallel between the nonlinear capacitors and a return conductor extending between the input and output terminals. The nonlinear capacitors have a capacitance characteristic that changes with the voltage applied across the capacitors, such as a capacitance that decreases with increasing voltage. A radio frequency signal source is coupled to the input terminals and provides power at a selected drive frequency. Depending on the frequency of the drive signal with respect to the Bragg cutoff frequency of the nonlinear transmission line, the output signal may include a strong signal component at the third harmonic of the input drive signal frequency, components at higher harmonics, or components at fractional frequencies of the input drive signal frequency.

Abstract: The invention relates to a circuit device for realizing a non-linear reactive elements scale network, wherein the non-linear elements of the network are pairs of inductive and capacitive components cascade connected between a pair of input terminals and a pair of output terminals. Advantageously in the invention, each component of the network is formed by cascade connecting a first and a second transconductance integrator with each other.

Abstract: Multilayer circuit boards include compensator networks configured in one or more conductor layers. A signal trace is configured in one or more layers to transmit an electrical signal from an input to an output and the compensator network is situated at at least one location on the trace to provide compensation for frequency dependent signal propagation losses or distortions such as those due to dielectric loss. In one example, the compensator includes a high frequency path provided by a series capacitance formed by conductor layers that include interleaved digits. Transmitters that include such compensators provide predistorted signals that can be matched or otherwise associated with anticipated propagation losses and distortions. Methods of evaluating dielectric losses include propagating electrical signals through such compensators and along a trace defined with respect to a dielectric under test and determining an associated compensation.

Abstract: A current mode output driver includes a pre-driver for pre-equalization. The current mode output driver drives a transmission line with an alternating current (AC) signal and a direct current (DC) signal. Characteristics of the transmission line are measured by comparing a received amplitude of the AC signal and a received amplitude of the DC signal. A ratio of the AC received amplitude to the DC received amplitude is compared to ratios derived from possible equalization settings to determine an equalization setting appropriate to equalize the channel.

Abstract: A monolithic non-linear transmission line and sampling circuit with reduced shock-wave-to-surface-wave coupling are presented herein. In coplanar-waveguide (CPW) technology, this reduced coupling is achieved by selecting properly the thickness of the semiconductor substrate, and by elevating the center conductor of the CPW above the substrate surface. The elevated center conductor is supported by means of conducting posts, and may be backed by a low-loss dielectric such as polyimide or silicon nitride. In coplanar-strip (CPS) technology, the reduction in coupling between shock waves and surface waves is achieved by controlling the substrate thickness as in the CPW case, and by elevating the coplanar strips above the substrate surface. The elevated strips are supported by a low-loss dielectric. The reduced coupling in both guiding media enhances the high-frequency performance of nonlinear-transmission-line-based circuits.

Abstract: A compact broadband balun (20). The balun (20) includes a waveguide transition (38) between one or more input ports (34, 54, 56) and one or more output ports (34, 54, 56) of the balun (20). A mechanism (36, 44), which depends on the tapered transition (38), provides a good match, while a resistor (44) provides isolation between input ports (34, 54, 56) and the output ports (34, 54, 56). In a specific embodiment, the balun (20) includes a first waveguide (34). One end of the first waveguide represents a first port of the balun (20). The balun (20) further includes a second wave guide (40, 42). Opposite ends (54, 56) of the second waveguide (40, 42) represent second (54) and third (56) ports. The waveguide transition (38) occurs between the first waveguide (34) and the second waveguide (40, 42). The waveguide transition (38, 44) is designed to provide a frequency-independent anti-phase response in response to an input signal provided at an input port (34).

Abstract: A method and an apparatus are provided for filtering a substantially square wave signal. At least a portion of the substantially square wave signal is applied to a first filter adapted to pass a range of frequencies adjacent the fundamental frequency and produce a first filtered signal. At least a portion of the substantially square wave signal is also applied to a plurality of second filters, where each of the second plurality of filters is adapted to pass a range of frequencies adjacent an odd harmonic component of the fundamental frequency and produce a second filtered signal. The first signal and the plurality of second filtered signals are combined to produce a representation of a square wave signal having a frequency substantially corresponding to the fundamental frequency.

Abstract: The septum is extended through the opening to the radio wave receiving portion to separate respective polarized waves received by a pair of radio wave receiving portions, and a space between the septum and the radio wave receiving portion is set such that an end surface of the waveguide on the side of the substrate is surely in contact with a grounding surface provided on one surface of the substrate, and an end surface of the radio wave reflecting portion on the side of the substrate is surely in contact with the grounding surface provided on the other surface of the substrate.

Abstract: Systems and methods are described for transmitting a waveform having a controllable attenuation and propagation velocity. An exemplary method comprises: generating an exponential waveform, the exponential waveform (a) being characterized by the equation Vin=De?ASD(x?vSDt), where D is a magnitude, Vin is a voltage, t is time, ASD is an attenuation coefficient, and VSD is a propagation velocity; and (b) being truncated at a maximum value. An exemplary apparatus comprises: an exponential waveform generator; an input recorder coupled to an output of the exponential waveform generator; a transmission line under test coupled to the output of the exponential waveform generator; an output recorder coupled to the transmission line under test; an additional transmission line coupled to the transmission line under test; and a termination impedance coupled to the additional transmission line and to a ground.

Abstract: A method of providing real time digital pulse shaping includes: receiving a digital pulse input signal (31); applying the digital pulse input signal to first (33, 34, 35) and second (32, 36, 37) processing channels, the first processing channel including a CONCAVE shaper (34) and the second processing channel including a CONVEX shaper (36); applying selected digital control parameters to the CONCAVE shaper (34) and the CONVEX shaper (36) to produce desired first and second weigthing functions, and superposing the first and second weighting functions to produce a desired overall weighting function.

Abstract: A device and a method for generating intense and brief variations of magnetic pressure, predetermined and controlled, capable of being isentropic inside a sample (23) of solid material. An electromagnetic cell (1) includes a flat parallel line of conductive material having two branches (4, 5) in the form of planar plates, of similar shapes and dimensions, separated from each other by a distance of not more than 3 mm, one of which (4) bears the sample (23) rigidly fixed on the branch (4), the two branches (4, 5) being electrically connected to each other by an end junction strip (7), and electrically connected, opposite the end junction strip, to elements (2, 3) generating electric current pulses so as to produce in less than 500 ns an electric current flowing in the electronic cell (1).

Abstract: A monolithic non-linear transmission line and sampling circuit with reduced shock-wave-to-surface-wave coupling are presented herein. In coplanar-waveguide (CPW) technology, this reduced coupling is achieved by selecting properly the thickness of the semiconductor substrate, and by elevating the center conductor of the CPW above the substrate surface. The elevated center conductor is supported by means of conducting posts, and may be backed by a low-loss dielectric such as polyimide or silicon nitride. In coplanar-strip (CPS) technology, the reduction in coupling between shock waves and surface waves is achieved by controlling the substrate thickness as in the CPW case, and by elevating the coplanar strips above the substrate surface. The elevated strips are supported by a low-loss dielectric. The reduced coupling in both guiding media enhances the high-frequency performance of nonlinear-transmission-line-based circuits.

Abstract: A method and an apparatus are provided for filtering a substantially square wave signal. At least a portion of the substantially square wave signal is applied to a first filter adapted to pass a range of frequencies adjacent the fundamental frequency and produce a first filtered signal. At least a portion of the substantially square wave signal is also applied to a plurality of second filters, where each of the second plurality of filters is adapted to pass a range of frequencies adjacent an odd harmonic component of the fundamental frequency and produce a second filtered signal. The first signal and the plurality of second filtered signals are combined to produce a representation of a square wave signal having a frequency substantially corresponding to the fundamental frequency.

Abstract: Scheme for processing an input signal A(t) by N resonators (17), each having parameters characterizing it, to generate N individual output signals. Then each of the N individual output signals is weighted using a corresponding weight to generate N individual weighted output signals which are superposed to obtain M output signals C(t). One of the parameters or the weight depend on a time signal P(t).

Abstract: A double waveform method for driving a transmission line at an initial voltage to a final voltage is provided. The method includes finding a first voltage, a first maintenance period for the first voltage, a second voltage and a second maintenance period for the second voltage according to the initial voltage and the final voltage. The first voltage is put on the transmission line for a period equal to the first maintenance period. Thereafter, the second voltage is put on the transmission line for a period equal to the second maintenance period. Finally, the final voltage is put on the transmission line. With this transmission arrangement, a stable and correct signal voltage is transmitted through a transmission line faster.

Abstract: Dynamic time expansion or compression of a small-amplitude input signal generated with an initial scale is performed using a nonlinear waveguide. A nonlinear waveguide having a variable refractive index is connected to a bias voltage source having a bias signal amplitude that is large relative to the input signal to vary the reflective index and concomitant speed of propagation of the nonlinear waveguide and an electrical circuit for applying the small-amplitude signal and the large amplitude bias signal simultaneously to the nonlinear waveguide. The large amplitude bias signal with the input signal alters the speed of propagation of the small-amplitude signal with time in the nonlinear waveguide to expand or contract the initial time scale of the small-amplitude input signal.

Abstract: A nonlinear transmission-line waveform generator for generating a comb of frequencies and relatively short duration pulses, for example, in the range of picoseconds and tens of picoseconds, that are adapted to being utilized with ultra wideband radios in order to improve the bandwidth of such radios by an order of magnitude, for example, up to tens and even hundreds of GHz. In particular, the nonlinear transmission line waveform generator in accordance with the present invention consists of a microstrip or coplanar waveguide line. In accordance with an important aspect of the invention, the &Dgr;C/&Dgr;V characteristic of the nonlinear transmission line is matched to the frequency and amplitude of the input sinusoidal waveform.

Abstract: A signal transmission system of the present invention has an output impedance Zs of a driving circuit, a characteristic impedance ZsO of the first transmission line, and a characteristic impedance ZO of a second transmission line are adjusted to satisfy a mathematical relation of: Zs<ZsO<ZO to provide a waveform of input of a receiving circuit with an overshoot characteristic. In the signal transmission system of the present invention, furthermore, ma time obtained by doubling a transmission time of the first transmission line with Ls in line length is shorter than a rise time Tr and a fall time Tf of the signal at an output end of the second transmission line.

Abstract: Systems and methods are described for transmitting a waveform having a controllable attenuation and propagation velocity. An exemplary method comprises: generating an exponential waveform, the exponential waveform (a) being characterized by the equation Vin=De−ASD[x−vSDt], where D is a magnitude, Vin, is a voltage, t is time, ASD is an attenuation coefficient, and vSD is a propagation velocity; and (b) being truncated at a maximum value. An exemplary apparatus comprises: an exponential waveform generator; an input recorder coupled to an output of the exponential waveform generator; a transmission line under test coupled to the output of the exponential waveform generator; an output recorder coupled to the transmission line under test; an additional transmission line coupled to the transmission line under test; and a termination impedance coupled to the additional transmission line and to a ground.

Abstract: The principal reason that commercially available 10 gigabits per second electrical interconnect has not previously been available is that such interconnect structures possess too high a level of parasitic inductance, capacitance, resistance and conductance. These result in signal degradation as a result of attenuation, harmonic distortion and dispersion and so sufficiently error-free transmission of data has been virtually impossible for high data rates such as those around 5 gigabits per second and above. By providing compensation mechanisms, signal integrity is improved thus enabling reliable data transmission at data rates of 5 gigabits per second, 10 gigabits per second and above. Non-linear transmission lines are used to form these compensation mechanisms. The non-linear transmission line may take the form of a distributed diode, for example, formed from a layer of N-doped silicon covered on its top surface by a layer of platinum and on its bottom surface by a layer of silicon dioxide.

Abstract: The septum is extended through the opening to the radio wave receiving portion to separate respective polarized waves received by a pair of radio wave receiving portions, and a space between the septum and the radio wave receiving portion is set such that an end surface of the waveguide on the side of the substrate is surely in contact with a grounding surface provided on one surface of the substrate, and an end surface of the radio wave reflecting portion on the side of the substrate is surely in contact with the grounding surface provided on the other surface of the substrate.

Abstract: An ultrafast sampling system includes an interposer and a sampler that include series of Schottky diodes configured with a non-parallel waveguide to form shocklines or nonlinear transmission line (NLTLs) that produce a differential strobe pulse. The shocklines are defined by non-parallel conductors that are configured as, for example, triangular, dentate, arcuate, or other shapes, or as conductors that have edges that are triangular, dentate, arcuate, or the like. The conductors are defined with respect to a substrate, and are airbridged so that at least some portions of the conductors are displaced from the substrate to reduce waveguide capacitance. Electrical connection to the sampler is made with airline having a inner conductor that is deformable to contact an input pad defined on the sampler.

Abstract: A non-linear transmission line has high temperature superconductive elements periodically loaded thereon. The elements have non-linear characteristics that provide voltage dependent non-linearity to the transmission line. The line can have a circuit with a first layer and a second layer with the second layer having several interdigital circuits printed thereon. The line can also have a meandering configuration or a spiral configuration.

Abstract: An ultrafast sampler includes a series of Schottky diodes configured with a coplanar waveguide to form a nonlinear transmission line (NLTL) that compresses a local oscillator input to form a series of strobe pulses. Strobe pulses of opposite polarity are capacitively coupled to sampling diodes to obtain samples of a signal applied to a signal input. The samples are directed along an intermediate frequency waveguide to, for example, a signal processor such as an oscilloscope, for storage and analysis. The intermediate frequency waveguide is configured so that conductors of the intermediate frequency waveguide receive signal samples of a common polarity and strobe samples of opposite polarities so that portions of strobe pulses delivered to a signal processor are distinguished from signal samples.

Abstract: Methods for driving a lossy transmission media with an energy wave defined by a an exponential waveform function. The propagation delay and attenuation of the wave is a function of an exponential coefficient, and its propagation velocity is essentially constant and independent of displacement. Utilizing relationships between the propagation velocity, exponential coefficient, attenuation, and transmission line parameters, one may effectively model various transmission media. One may also determine unknown transmission line parameters, waveform exponential coefficients, attenuation, and/or propagation velocities by utilizing those relationships. By modulating the exponential coefficient, information may be encoded onto a waveform.

Abstract: A pulse generator generates a pulse that is transmitted to a device under test through a signal path that has a substantially constant impedance along its entire length. A voltage on the signal path and a current therethrough is measured in response to the pulse being generated.

Abstract: A method for generating a closely spaced train of extremely high voltage short pulses. The method involves generating the train of pulses by combining a plurality of harmonic amplitudes to construct said pulses, via a Fourier construction. Any arbitrary pulse shape can be reproduced simply by changing the amplitude of the harmonics. The train of high voltage electrical pulses produced by the method of the present invention is particularly well suited for the acceleration of particles by applying the pulses to an appropriate accelerating structure, or the pulses can be used to drive an undulator/wiggler.

Abstract: An improved, more intelligent network interface unit capable of processing signals received from a high speed transmission media and outputting the received signals without substantial amplification or reduction. The network interface unit comprises a regenerator circuit which detects T1 signals from said high-speed transmission media and outputs a digital stream to a serial data processor for processing via a micro-controller. A wave shaper circuit receives the output from the serial data processor and, in conjunction with the micro-controller and a level detector circuit, regenerates signals having substantially the same wave shape and amplitude as the original T1 signals received from said transmission media.

Abstract: An apparatus and method for treating exhaust gases. In this apparatus, a plurality of stages of reactor chambers (R1, R2, . . . Rn) are connected in series in the direction of an exhaust gas flow. Further, high-voltage power supplies (V1, V2, . . . and Vn) are connected to the reactor chambers (R1, R2, . . . and Rn), respectively. Moreover, in each of these reactor chambers, a streamer discharger plasma is generated. Furthermore, the more downstream a reactor chamber of a stage is placed, the lower energy to be cast into the reactor chamber becomes. The density of electrons generated in a gas decomposition unit is high in a portion thereof on the upstream side of the exhaust gas flow and the electron density is low in a portion thereof on the downstream side. Additionally, the present invention further provides a pulse generator in which a high voltage, which is an output voltage of a D.C.