Abstract: An antimicrobial device, such as a flashlight, lantern, or lamp, is discussed herein. The antimicrobial device produces light in the ultraviolet (UV) spectrum (i.e., 150-250 nm), including 200-230 nm. The antimicrobial device includes an electron source, an extractor, and a target material. The electron source provides the electrons of sufficient energy to cause a photon to be released, whether by a target or by the electron itself. The extractor extracts the electrons from the electron source. The target material is a component at which the electron is directed. The target material can release a photon having a desired wavelength or within a desired wavelength range or cause the electron to release a photon having a desired wavelength or within a desired wavelength range.

Abstract: A circuit is presented which includes a first amplifier having an input, a transmission line having first and second ends. The first end of the transmission line is coupled to an input of the first amplifier and a plurality of channels. Each channel includes a plurality of resonators arranged to read out a plurality of qubits, respectively and a readout line arranged to receive read out signals from the plurality of resonators. The readout line of each channel is coupled to the transmission line and each channel is configured to output a respective signal in a respective frequency band which is different from frequency bands of other channels in the plurality of channels.

Abstract: A liquid treatment device comprising: two antennae; an enclosure for holding a liquid including a solvent and a solute; a generator operatively connected to the two antennae to generate an oscillating voltage in each antenna, wherein each voltage is out of phase with the other to create an oscillating electric-field; and the liquid in the enclosure being subjected to the electric-field in the presence of a magnetic field to change the chemical and/or physical properties of the solute, without the liquid contacting the two antennae.

Abstract: Described herein is a method and apparatus for removing metal oxides on a surface of a component via electron attachment. In one embodiment, there is provided a field emission apparatus, wherein the electrons attach to at least a portion of the reducing gas to form a negatively charged atomic ions which removes metal oxides comprising: a cathode comprising an electrically conductive and comprising at least one or more protrusions having an angled edge or high curvature surface, wherein the cathode is surrounded by a dielectric material which is then surrounded by an electrically conductive anode wherein the cathode and anode are each connected to an electrical voltage source, and the dielectric material between the cathode and anode is polarized, intensifying the electrical field strength and accumulating electrons at the apex of the cathode to promote field emission of electrons from the cathode.

Abstract: Various apparatuses and methods for a vacuum electronic device are disclosed herein. In one embodiment, a vacuum electronic device includes a vacuum housing, an array of slow wave structures inside the vacuum housing sharing a common electron beam tunnel, an electron beam input port at a first end of the common electron beam tunnel, and an electron beam output port at a second end of the common electron beam tunnel.

Abstract: A voltage control apparatus used for an electron tube or a power supply apparatus includes a detecting circuit for detecting current flowing through a helix electrode, a voltage-limiting circuit for controlling a potential difference between the helix electrode and the anode electrode based on a predetermined voltage level; and a switch for switching based on an output from the detecting circuit. The switch connects the helix electrode and the anode electrode through the voltage-limiting circuit, or causes a short circuit between the helix electrode and the anode electrode.

Abstract: A method for pre-distorting an input for a device is provided. A partial set of known data pairs is acquired during a closed-loop device calibration period. The partial set of known data pairs is searched for at least one missing data pair, and at least one data value is interpolated for the missing data pair. An augmented set of data pairs, including the known data pairs and the interpolated data value, is stored in a lookup table. During an open-loop operation period subsequent to the closed-loop device calibration period, the device input is pre-distorted based on the augmented set of data pairs stored in the lookup table.

Abstract: A power supply apparatus for a traveling-wave tube includes an electrical discharge switch and a first resistor that are serially connected, and that are connected between a cathode electrode and a first collector electrode; N (N denotes a positive integer) arresters that are serially connected, and that are inserted between a ground potential and a connection node of the electrical discharge switch and the first resistor; N second resistors that are inserted between the N arresters and a second collector electrode to an Nth collector electrode and a ground potential, respectively; and an electrical discharge control circuit that turns off the electrical discharge switch at a time of normal operation of the power supply apparatus and turns on the electrical discharge switch when stopping operation of the power supply apparatus.

Abstract: A resonant amplifier is provided. A resonant inductor is connected in series between a source (emitter) of a common gate (base) transistor and an input point (i.e. output point of previous stage), and a resonant capacitor is connected between the input point and a ground or a voltage source connected to a loading end, such that a lossy resonant cavity is formed for carrying out resonance to amplify the signal. Then, the amplified signal is drawn out by the common gate (base) architecture. Therefore, the gain of the resonant amplifier can be boosted at desired frequency.

Abstract: An amplifier including an electronic tube with an axial electron beam, provided with a cathode and at least two collectors, and at least two sources of DC voltage. Each collector is connected to a DC voltage source having a potential difference such that, the further the collector is from the cathode, the lower the potential difference between this collector and the cathode. The DC voltage sources are connected together at a common point situated at the collector whose potential difference with the cathode is the lower but not zero.

Abstract: The invention relates to a microwave tube comprising an electron gun generating an electron beam in a cylindrical microwave structure of the tube. The microwave structure delivers a microwave at one output. A collector for collecting electrons from the beam comprising at least one electrode that is mechanically coupled to the microwave structure via a dielectric, the mechanical coupling forming a radial waveguide for propagating spurious microwave radiation (Pr) from the tube. In order to attenuate the spurious radiation from the tube, the radial waveguide (Wg) includes at least one quarter-wave microwave trap having, at least at the operating frequency F of the tube, an open circuit for the microwave propagating in said radial waveguide for propagating spurious radiation.

Abstract: Generating and frequency tuning of modulated high current electron beams and a specific efficient, high current, frequency-tunable device for generating intense radio frequency (RF), microwave electromagnetic fields in a rectangular waveguide. Current multiplication of a modulated seed electron beam is created by an energetic electron beam impacting a thin foil surface. The transmissive-electron-multiplier foils also mitigate both space charge expansion and improve beam propagation effects, by shorting of the radially directed electric field at the axial location of the foil(s). Foil thinness and intensity of the exit fields provide for a multiplication process occurring in a fraction of an RF period. Also included are both a self-excited microwave generator and an amplifier, using a temporally modulated laser to generate a modulated seed electron beam that is amplified. Methods to tune the oscillator are described that allow tunability over a full waveguide band.

Abstract: An inductive output tube (IOT) provides improved efficiency and larger bandwidth. In one embodiment, an IOT is provided with an electron gun that generates an electron beam, a tube body, a collector for collecting the electron beam, and an extended-interaction output circuit. The electron beam travels through the tube body and the extended-interaction output circuit. The extended-interaction output circuit is located within the tube body. The extended-interaction output circuit comprises a short-circuited resonant structure. The extended-interaction output circuit is used for reducing undesired components of a radio frequency (RF) wave, increasing desired components of the RF wave, and slowing down the propagation of the RF wave. (That is the circuit increases the integral of the electric field along the path of the beam electrons while decreasing the stored energy associated with those fields.) The extended-interaction output circuit also provides the IOT with larger bandwidth operation.

Abstract: In a multistage collector used in a linear beam tube such as an IOT or klystron, electrode stages are separated by ceramic rings having metallised surfaces to provide distributed bypass capacitors. This eliminates or reduces leakage or any radio frequency energy from the interior of the collector to the outside.

Abstract: A depressed collector for recovery of spent beam energy from electromagnetic sources emitting sheet or large aspect ration annular electron beams operating aver a broad range of beam voltages and currents. The collector incorporates a trap for capturing and preventing the return of reflected and secondary electrons.

Abstract: An optical switch configured to reduce packet-to-packet optical power variation corresponding to different switch channels. The optical switch includes a plurality of optical amplifiers coupled to the input or output ports of an optical switch fabric (OSF), e.g., an arrayed waveguide grating. Each amplifier may be a semiconductor optical amplifier configured to operate in the saturated regime. In addition, the maximum output power of each amplifier may be set to a different value related to the insertion loss in the OSF. As a result, at each receiver corresponding to an output port of the OSF, the optical power corresponding to data packets arriving from different input ports may be substantially equalized. Such equalization may reduce the number of bit errors in the switch.

Abstract: A given high frequency electric power introduced into a cavity resonator is resonated in the long direction of the cavity resonator on an excited mode with a constant electric field intensity along the long direction of the cavity resonator. Then, a human body is set on a table 2 in the cavity resonator so that its body axis can match the long direction of the cavity resonator. Then, the resonated high frequency electric power is applied to the human body.

Abstract: A uniform-field resonator includes a central cavity section having a cross-section which is set to the cutoff frequency for a particular microwave propagation mode and a pair of end sections which enclose the cavity to form a resonator in which the field is substantially uniform along the entire length of the central cavity—regardless of its length. A number of end section design strategies and resulting structures are described for supporting the uniform-field mode of operation in the central cavity section.

Abstract: A linear amplifier comprises an electron gun assembly having a cathode, and an anode spaced from the cathode. A relatively high voltage potential is applied between the anode and the cathode, and the cathode provides an electron beam in response to the relatively high voltage potential. A control grid is spaced between the cathode and the anode, and is coupled to an input port adapted to receive the input signal. The input signal causes the control grid to density modulate the beam. The control grid is also coupled to a bias voltage source to preclude transmission of the electron beam during the negative half cycle of the input signal. A plurality of collector stages are provided with a respective electric potential thereto ranging between a potential of the cathode and a potential of the anode to efficiently collect the electrons of the beam after passing the anode.

Abstract: The disclosure relates to a radiofrequency generator including an Inductive Output Tube with an electron gun followed by an anode, the gun being raised to a high voltage in use, means producing an input radiofrequency signal and means of transmitting it to said IOT such that it provides an output signal whose power is amplified compared to said input signal, wherein said means producing said input radiofrequency signal, said means transmitting it to said IOT and said gun are confined in an electrostatically screened enclosure that is electrically isolated from the potential of the anode and can be raised to a high voltage, said gun receiving its high voltage from said screened enclosure. The invention is applicable to very high power radiofrequency generators.

Abstract: A linear amplifier comprises an electron gun assembly having a cathode, and an anode spaced from the cathode. A relatively high voltage potential is applied between the anode and the cathode, and the cathode provides an electron beam in response to the relatively high voltage potential. A control grid is spaced between the cathode and the anode, and is coupled to an input port adapted to receive the input signal. The input signal causes the control grid to density modulate the beam. The control grid is also coupled to a bias voltage source to preclude transmission of the electron beam during the negative half cycle of the input signal. A plurality of collector stages are provided with a respective electric potential thereto ranging between a potential of the cathode and a potential of the anode to efficiently collect the electrons of the beam after passing the anode.

Abstract: A signal output assembly for an inductive output amplifier comprises a primary output cavity including a drift tube enclosing a modulated electron beam. The density modulated beam passes across a gap separating portions of the drift tube and induces an amplified RF signal into the primary output cavity. A secondary output cavity comprises a coaxial resonator terminated in an inductive coupling loop, and a waveguide having a ridge. The coaxial resonator and the inductive coupling loop have a combined electrical length approximately equivalent to an odd multiple of one-quarter wavelengths of the input signal (n&lgr;/4), where n is an odd integer. The coaxial resonator is electrically connected perpendicularly to a center of the ridge such that first and second portions of the ridge extend in opposite directions from the connection with the coaxial resonator to respective ends of the waveguide.

Abstract: A frequency tuning device for a microwave tube. The tube has one or more resonant cavities which are tuned with the aid of a movable tuning element for each cavity. Each tuning element has an actuating device and a sensor which detects the position of the tuning element. An electronic control is provided for comparing the position of the tuning element supplied by the sensor with a set position and for delivering a control signal to the actuating device which moves the tuning element to the set position.

Abstract: A linear beam amplification device includes an axially centered electron emitting cathode and an anode spaced therefrom. The cathode provides an electron beam in response to a relatively high voltage potential defined between the cathode and the anode. A control grid is spaced between the cathode and anode for modulating the electron beam in accordance with an input signal. A signal input assembly of the linear beam amplification device comprises an axial input cavity into which the input signal is inductively coupled. The grid-cathode region is electrically connected to the input cavity. A low impedance grid-anode cavity is disposed coaxially with the input cavity and is in electrical communication with an interaction region defined between the grid and the anode. The low impedance of the grid-anode cavity is provided by constructing the cavity of a material having a relatively high surface resistivity, such as iron.

Abstract: A linear electron beam tube such as an IOT includes an input cavity formed from an inner body portion and an outer body portion which are joined together by a ceramic cylinder. The input cavity surrounds an electron gun and permits electrical connection to be made to the cathode and grid via parts of the inner body portion and. Metallization layers in conjunction with the intervening ceramic material of the cylinder define rf chokes. The construction enables high voltage parts of the arrangement to be insulated from the low voltage outer body portion whilst presenting a low leakage path for r.f.

Abstract: Nonlinear current modulation of a relativistic electron beam is achieved by ts propagation without interruption through a resistive wall type of drift tube assembly within a klystron amplifier. Maximized beam current modulation is thereby attained for a beam propagation distance within a shortened drift tube.

Abstract: The invention relates to a cathode ray tube having an input resonator cavity which includes a first metal wall (2) and, spaced apart therefrom, a second metal wall (3) each conveying a low electric potential and constituting coupling areas (6, 7) at axially spaced locations, in which areas metal elements (10, 12) conveying a high electric potential are located opposite surface sections (8, 9 and 14, 15) which are electrically connected to the metal walls (2, 3) via insulating dielectrics (11, 13), the coupling areas (6, 7) being separated by a spacing dielectric. A high-voltage stable arrangement which is resistant to temperature fluctuations is obtained in that the spacing dielectric consists of a different material than the insulating dielectrics (6, 7) and has a lower value of the product of loss factor and dielectric constant (tg.delta..times..epsilon.) at a high frequency.

Abstract: An inductive output tube, e.g., a KLYSTRODE, or a klystron, has a substantially hollow electron beam traversing a resonant cavity excited to the TM.sub.0x0 mode, where x is greater than 1.

Abstract: An r.f. radiation absorbing material able to hold off a 30 to 40 kV voltage difference is described as formed by a silicon rubber loaded with ferrite particles. The material is used to reduce self-oscillation in amplifiers.

Abstract: An electron tube includes cylindrical electrodes which are mounted coaxially. The electrodes include a cathode surrounded by a grid, with the cathode and the grid defining an input resonant cavity having an active zone. The cavity extends on both sides of the active zone. The central part of the active zone is located at a point where the voltage reaches a maximum. The resonant input cavity is folded back on itself so that both ends of the cavity are at the base of the tube.

Abstract: A high efficiency linear amplifier comprises an electron gun assembly having a cathode and an anode, the cathode being operable at a relatively high voltage potential relative to the anode to form and accelerate an electron beam. A control grid is disposed between the cathode and the anode, and is biased relative to the cathode for Class B operation. A high frequency input signal is applied to the control grid to density modulate the electron beam. A shadow grid may be disposed between the control grid and the cathode. A drift tube encloses the beam and includes a first portion and a second portion with a gap defined between the first and second portions. An inductive output cavity communicates with the gap, and the density modulated electron beam passed across the gap and induces an RF electromagnetic signal into the cavity. A multistage depressed collector accepts and dissipates the electrons of the beam which remain after transit across the gap.

Abstract: In an electron beam tube, such as an IOT, ferrite loaded silicone rubber or some other ferrite loaded dielectric material, is carried by a wall of an input cavity. The material absorbs r.f. energy, reducing coupling between different parts of the tube which could otherwise result in undesirable oscillation. Furthermore, its provision on part of the input cavity wall enables easy access to be made for replacement and servicing requirements.

Abstract: Nonlinear current modulation of a relativistic electron beam is achieved by ts propagation without interruption through a resistive wall type of drift tube assembly within a klystron amplifier. Maximized beam current modulation is thereby attained for a beam propagation distance within a shortened drift tube.

Abstract: An electron beam tube arrangement in an inductive output tetrode. The arrangement comprises a resonant cavity circuit having two cavities, and includes an element for coupling high frequency energy between the two cavities. The coupling element includes a coupling dome projecting into one of the two cavities from a wall thereof. The coupling dome has a base portion which is adapted to be connected to a dome completion member selected from a set comprising at least one dome completion member for adjusting a coupling level between the two cavities.

Abstract: A linear electron beam tube has voltages provided thereto, an electron gun, and an output resonant cavity operatively arranged together. An internal body portion, an external body portion and an insulating portion are provided. The internal body portion, external body portion, and insulating portion at least partially define an annular input resonant cavity. The internal body portion is provided with a high voltage, with respect to the external body portion, and the internal and external body portions are separated by the insulating portion so that the internal and external body portions have no electrically conductive connection therebetween. The internal body portion is in electrical contact with the electron gun. The annular input resonant cavity at least partially defined by the internal and external body portions surrounds the electron gun.

Abstract: An inductive output tetrode includes a cylindrical ceramic envelope within which is located an electron gun including a cathode and grid. An annular resonant input cavity into which a high frequency signal is coupled surrounds the envelope and is located adjacent the electron gun so as to provide a modulating electric field in the cathode-grid region to density modulate the electron beam. The input cavity is connected to two metal cylinders arranged immediately adjacent to the outside of the envelope. Metallic portions located within the envelope are co-extensive with cylinders with the material of the envelope 1 being located between them. These structures act as r.f. chokes to reduce high frequency losses from the input cavity. Tuning of the resonant cavity may be achieved by adjusting a tuning member which is at distance of quarter of a wavelength at the resonant frequency from the cathode-grid region.

Abstract: In signal processing circuitry using active devices, non-linearity of the device causes distortion of pure tones and the generation of intermodulation products for more complex signals. The transfer characteristics of such active devices may be considered as the accumulated characteristics of input and output filter stages separated by a non-linear region. To compensate for non-linearities and reduce intermodulation products, a drive circuit comprises pre- and post-correction filters separated by a compensating amplifier. The frequency response of the pre-correction filter corresponds to that of the input filter stage but is reversed in the frequency spectrum; with conventional I.F. the transfer characteristic of the amplifier and frequency response characteristic of the post-correction filter are the respective complements, of those of the non-linear region and pre-correction filter.

Abstract: A method for suppressing second and higher harmonic power generation in a klystron is described. The klystron includes a series of cavities that are connected to a series of connecting drift tubes, and one or more waveguide loads are placed on selected ones of the drift tubes or cavities, for reducing the second and higher harmonic power by causing it to be loaded out progressively, at predetermined discrete intervals. In the preferred embodiment, the inner diameter of the drift tubes is such that the cutoff frequency is above the fundamental operating frequency of the klystron, which will allow frequencies greater than the fundamental frequency, and particularly the second harmonic frequency, for example 22.848 GHz, to propagate. In one example, each of the four pre-selected drift tubes is loaded with two generally diametrically oppositely positioned waveguide loads. In another example, each of four drift tubes is loaded with three equidistally positioned waveguide loads.

Abstract: A submillimeter wave-generating integrated circuit includes an array of N photoconductive switches biased across a common voltage source and an optical path difference from a common optical pulse of repetition rate f.sub.0 providing a different optical delay to each of the switches. In one embodiment, each incoming pulse is applied to successive ones of the N switches with successive delays. The N switches are spaced apart with a suitable switch-to-switch spacing so as to generate at the output load or antenna radiation of a submillimeter wave frequency f on the order of Nf.sub.0. Preferably, the optical pulse has a repetition rate of at least 10 GHz and N is of the order of 100, so that the circuit generates radiation of frequency of the order of or greater than 1 Terahertz.

Abstract: The voltage variation between the electrodes of the tube of a microwave amplifier (1) causing a phase Shift of the output wave from the microwave amplifier (1), the process according to the invention consists of creating a phase shift of the wave entering the tube of the microwave amplifier (1) that is substantially proportional to the voltage variation and in the direction opposite the phase shift of the output wave caused by this voltage variation.

Abstract: A body of dense plasma is established within a short drift tube of a klysn amplifier between input and output resonator cavities thereof to support current modulation of microwave energy by interaction with an electron beam propagated through the drift tube. The plasma is confined to a column radially spaced from the electron beam for two-stream interaction enabling enhancement of current modulation under simultaneous high-power and high frequency operation.

Abstract: An electronic device for amplifying microwave or millimeter wave signals. A microwave or millimeter wave input signal stimulates a gated field emission array to produce a density modulated beam of electrons containing about 1 billion to 1,000 billion bunches or pulses per second which in turn illuminates a thin diamond target in a diamond switch connecting a load to a high voltage source. Each electron in each pulse creates a large number of electron hole pairs in the diamond. The high voltage bias across the diamond causes most of the very large number of pairs to be swept through the diamond target producing a high current surge in less than one half the period of the designed output frequency. Induced RF currents are set up within the resonant output cavity in response to the current flowing within the diamond. In summary, each surge of current produces an electromagnetic pulse at the load. Thus, an electromagnetic millimeter wave is produced with a frequency equal to the frequency of the signal output.

Abstract: An extended interaction output circuit interacts with a modulated electron beam and outputs RF electromagnetic energy. The circuit comprises a plurality of linearly disposed cavities each having a gap permitting the traveling therethrough of the modulated electron beam. A first pair of the linearly disposed cavities is coupled by a single side cavity, a second pair of the linearly disposed cavities is coupled by a pair of side cavities radially disposed 180 degrees apart, and a third pair of the linearly disposed cavities is coupled by three side cavities radially disposed 120 degrees apart. The linearly disposed cavities act as an RF filter having successively tapered impedances to reduce reflections of the electromagnetic energy propagating through the circuit. RF energy is extracted from the fourth cavity through four waveguide sections that are radially disposed 90 degrees apart.

Abstract: In a klystron, or other device which uses modulation of an electron beam to produce amplification of an applied high frequency signal, a collector is used to receive electrons of the beam after the amplified signal has been coupled from the device. Any secondary electrons produced by the impact of high energy electrons on the collector surface are prevented from returning back along the klystron by a periodic magnetic field produce by magnets which coaxially surround the collector.

Abstract: An amplifying arrangement employs both density and velocity modulation of an electron beam in order to produce amplification of a high frequency signal. In one embodiment, density modulation is produced at the cathode region, a first carrier signal being applied between a cathode and a modulation grid to produce bunching of electrons. The density modulated electron beam is then velocity modulated at a first resonant cavity. It is preferred that the first carrier signal is twice the frequency of the carrier signal producing the velocity modulation. The arrangement may be such that, at the final resonant cavity, adjacent electron bunches produced by density modulation combine, thus giving a high efficiency amplifying arrangement.

Abstract: An electron beam tube arrangement has an output cavity resonator circuit which includes a first output cavity, a second output cavity being coupled thereto by means of a coupling loop. The coupling loop is located in the first cavity and connected to said second cavity. In one embodiment of the invention, the second cavity also contains a coupling loop which is electrically connected to that in the first output cavity.

Abstract: Two or more signal interaction structures (16,18), which may be klystron or traveling wave structures (32,50), are axially disposed in series between an electron gun (12) and a collector (14) for selectively velocity modulating an electron beam (20) generated by the gun (12) with a microwave input signal (IN1,IN2) and extracting a resulting amplified microwave output signal (OUT1,OUT2) from the beam (20). The interaction structures (16,18) are designed to operate in different frequency bands, for example the X and Ku bands, with only one of the structures (16,18) having an input signal (IN1,IN2) applied thereto at any given time. The interaction structures (16,18) are further designed such that the structures (16,18) which are not being used do not affect the structure (16,18) which is being used.

Abstract: The present invention is a coupled cavity gyrotron-traveling-wave-tube amplifier which produces highly efficient, broad band millimeter wave radiation. The present invention comprises an electron gun, a double ridged coupled cavity interaction circuit and a beam collector. In operation the gun injects a gyrating electron beam through a beam tunnel of a side wall of the coupled cavity. When the electron beam phase is synchronized with the rf phase of the transverse electric mode in the coupled cavity circuit, the electron beam is modulated and amplifies the rf input signal through the negative mass instability called electron cyclontron instability. The coupled cavity design of the interaction circuit effctively slows the rf-wave velocity, allowing amplification of the rf- wave over a broad band. This t ype of broad band microwave energy is highly useful in radar, communications and jamming technology.

Abstract: A high power, highly efficient, phase-stable frequency-multiplying magnicon microwave amplifier is disclosed having efficiencies that exceed 60%. The magnicon amplifier has an output cavity that receives an electron beam that is deflection modulated by the drive, gain and penultimate cavities of the magnicon amplifier. The output cavity is dimensioned so as to operate in a TM.sub.m10 mode, where m is an even integer greater than two. The output cavity is selected to preferably have an operating frequency f.sub.o which is twice the cyclotron frequency f.sub.c of the output cavity.

Abstract: In signal processing circuitry using active devices, non-linearity of the device causes distortion of pure tones and the generation of intermodulation products for more complex signals. The transfer characteristics of such active devices may be considered as the accumulated characteristics of input and output filter stages separated by a non-linear region. To compensate for non-linearities and reduce intermodulation products, a drive circuit comprises pre- and post-correction filters separated by a compensating amplifier. The frequency response of the pre-correction filter corresponds to that of the input filter stage but is reversed in the frequency spectrum; with conventional I.F. the transfer characteristic of the amplifier and frequency response characteristic of the post-correction filter are the respective complements, of those of the non-linear region and pre-correction filter.