| 序号 | 专利名 | 申请号 | 申请日 | 公开（公告）号 | 公开（公告）日 | 发明人 |
|---|---|---|---|---|---|---|
| 81 | Return to zero and sampling pulse generating circuits and method for direct digital up conversion | US10113279 | 2002-04-01 | US06617938B1 | 2003-09-09 | James J. Komiak |
| Direct up-conversion of a signal is accomplished using a sampling pulse generator circuit and a gated differential amplifier, enabled by the sampling signal. When not enabled, the output of the differential amplifier is pulled to zero. The sampling pulse is generated from a base frequency sine wave which is squared with a limiting amplifier, and further passed through one or more frequency doublers producing a times two signal, a times four signal and so on. The squared base frequency and frequency doubled signals are logically ORed to produce a short duration pulse which repeats at the frequency of the base signal. The resulting output is an amplitude modulated pulse doublet time domain waveform. | ||||||
| 82 | Low noise Gilbert Multiplier Cells and quadrature modulators | US925572 | 1997-09-08 | US5847623A | 1998-12-08 | Aristotle Hadjichristos |
| A Gilbert Multiplier Cell includes an emitter-coupled transistor pair and a pair of cross-coupled emitter-coupled transistor pairs. A filter couples the emitter-coupled transistor pair to the pair of the cross-coupled emitter-coupled transistor pairs. The filter may include a pair of inductors or resistors, a respective one of which serially couples a respective one of the emitter-coupled transistor pair to a respective one of the pair of cross-coupled emitter-coupled transistor pairs, and a capacitor connected between the pair of inductors or resistors. A local oscillator is coupled to the pair of cross-coupled emitter-coupled transistor pairs and a data input is coupled to the emitter-coupled transistor pair. By low pass filtering the output of the emitter-coupled transistor pair that is applied to the pair of cross-coupled emitter-coupled transistor pairs, low noise floor Gilbert Multiplier Cells and quadraphase modulators may be provided. | ||||||
| 83 | Amplitude modulation method and broadcasting apparatus for carrying out the method | US69922 | 1993-06-01 | US5454013A | 1995-09-26 | Michitosi Minami; Yutaka Kojima; Tetsuroh Miyazaki; Kazuhisa Hayeiwa; Hisashi Naka; Kazuaki Wakai; Tohru Mizokami |
| An amplitude modulation system. An input analog signal indicating audio, etc., is converted into a digital form and the low-order bits of the resultant digital signal are converted into analog form. The resultant analog signal is used to control a gain of an analog controlled amplifier. On the other hand, a plurality of digitally controlled amplifiers are selectively turned on/off in response to the value of the high-order bits of the digital signal. Carrier amplified by the analog controlled amplifier are combined with carriers amplified by the plurality of digitally controlled amplifiers. Comparatively rough amplitude constituents are provided by outputs of the plurality of digitally controlled amplifiers and comparatively fine amplitude constituents are provided by output of the analog controlled amplifier. | ||||||
| 84 | Linear-modulation type radio transmitter | US600379 | 1990-10-19 | US5113525A | 1992-05-12 | Akira Andoh |
| The present invention relates to a radio transmitter which transmits from an antenna a carrier wave linearly modulated based on a signal to be transmitted. Since a monitor wave with the predetermined level applied to a transmission power amplifier is amplified and the level of the amplified monitor wave is thereafter detected, followed by adjustment of the gain of the transmission power amplifier based on its level detected, or since the comparison between the level of an envelope component of a signal prior to modulation and that of an amplified signal is made and the gain of the transmission power amplifier is adjusted based on the result of its comparison, mean transmission power is maintained at a predetermined value. | ||||||
| 85 | RF power supply for supplying a regulated power amplified unmodulated drive signal to an RF modulator | US269158 | 1988-11-09 | US4947455A | 1990-08-07 | Hilmer I. Swanson |
| An RF power supply serves to supply a regulated power amplified RF drive signal to an RF transmitter. The supply includes an RF oscillator for providing an RF input signal. A DC voltage source provides a DC voltage V. A plurality of power amplifiers are provided with each receiving the input RF signal and each having an input for receiving a DC voltage signal, and each serving to amplify the input RF signal by an amount dependent upon the magnitude of the DC voltage signal supplied to its input and thereby provide an amplified RF signal. The amplified RF signals are combined to provide an RF drive signal. The DC voltage V is directly supplied to the input of at least a first one of the power amplifiers. A regulating means serves to regulate the magnitude of the RF drive signal with the regulating means including circuitry for applying a fractional portion of the DC voltage V to the input of at least a second one of the power amplifiers with the fractional portion varying as a function of any variation in the magnitude of the DC drive signal with respect to a desired magnitude thereof. | ||||||
| 86 | AM-RF transmitter with compensation for power supply variations | US832807 | 1986-02-25 | US4747161A | 1988-05-24 | Gilmer L. Hulsey; Bryan A. Weaver |
| An AM-RF transmitter includes a transmitter stage having a DC power supply terminal energized by an AC to DC converter including reactances having a resonant frequency approaching frequencies of an information, modulating signal. The voltage applied by the supply to the DC power supply terminal is reduced to such an extent as to induce distortion in the transmitted AM-RF carrier in response to the transmitter stage being modulated by positive amplitude variations having frequencies that approach the resonant frequency. The amplitude of the transmitter stage modulation is increased when the distortion would otherwise occur to substantially prevent the distortion. The information signal is modified in amplitude by only AC coupling a replica of the DC power supply voltage variations to one input of a four quadrant multiplier, having a second input responsive to the information signal. | ||||||
| 87 | Method and apparatus for reducing distortion in amplifiers | US922761 | 1986-10-24 | US4737731A | 1988-04-12 | Hilmer I. Swanson; Scott A. McFarland |
| Amplitude modulation apparatus is provided having means for providing a radio frequency carrier signal, and means for receiving an audio frequency signal to be used to amplitude modulate the RF carrier signal. Amplitude modulator means is provided responsive to the AF signal and to the RF carrier signal for amplitude modulating the RF carrier signal in accordance with the AF signal so as to thereby provide an amplitude modulated RF carrier signal. A power supply provides at least one DC power signal for powering the amplitude modulator means. Correction means is included for sensing variations in the DC power signal and for gain adjusting the audio frequency signal in accordance with the variations in the DC power signal, whereby modulation distortion of the amplitude modulated RF carrier signal is reduced. | ||||||
| 88 | RF amplitude modulator/mixer | US859486 | 1986-05-05 | US4698603A | 1987-10-06 | George A. Clarius |
| A method and apparatus are disclosed for offsetting the DC level of a modulating signal input to a dual balanced modulator. The circuit is adapted to offset a high frequency modulation signal by an amount sufficient to provide the optimum percent modulation of a carrier signal applied to the dual balanced modulator. The offset level to be applied is dependent upon the desired percent modulation and is further affected by the operating modulation and carrier frequencies as well as their respective input power levels. | ||||||
| 89 | Radio transmitter modulation control circuitry | US613742 | 1984-05-22 | US4491972A | 1985-01-01 | Paul J. Weber |
| Improved radio transmitter modulation control circuitry is described which significantly increases the average power of the modulating signal, resulting in enhanced audio signal quality since the signal-to-noise ratio is likewise increased. The inventive modulation control circuitry includes a microphone 110, audio amplifier 120, splatter filter 130, modulator 150, potentiometer 140, oscillator and transmitter 180, and antenna 190. The audio amplifier 120 further includes an operational amplifier 160 having an input resistor 162 coupled via capacitor 168 to microphone 110, a phase-lag filter 170 coupled to the output of the operational amplifier 160, and a feedback resistor 161 coupled between the filter 170 and the input resistor 162. When driven into amplitude limiting, the phase and amplitude of harmonic signals from the operational amplifier 160 are altered by phase-lag filter 170 to produce a waveform similar to that shown in FIG. 2. When operated linearly, the audio amplifier 120 has a flat frequency response, the filter 170 having no effect since it is in the feedback loop. The improved modulation control circuitry of the present invention can be advantageously utilized in both amplitude and frequency modulated radios 100 for enhancing the audio signal quality thereof. | ||||||
| 90 | Automatic modulation control apparatus | US881100 | 1978-02-24 | US4199723A | 1980-04-22 | Forest M. Cummings; Jack S. Sellmeyer |
| The present invention concerns circuitry for comparing the output power of an amplitude modulated RF transmitter with the supply power to the RF transmitter and using feedback from a comparator to a variable gain modulation amplifier to maintain the level of modulation constant. The scheme is illustrated for four different basic types of RF amplitude modulated transmitters. | ||||||
| 91 | AM transmitter with an offset voltage to the RF stage to compensate for switching time of the modulators | US859189 | 1977-12-09 | US4122415A | 1978-10-24 | Arch Clinton Luther, Jr.; David Arthur Sauer |
| An AM transmitter of the type including apparatus for generating a subcarrier signal, pulse width modulating this subcarrier with audio, amplifying this resulting pulse width signal using active devices operating in the more efficient switching mode is disclosed. The amplified pulse width signal is passed through a low pass filter wherein the audio is recovered and used to amplitude modulate a radio frequency stage. The improvement herein includes a means for providing an offset voltage to the RF stage so that the system will develop zero carrier output when the pulse width of the modulating signal to the active devices has a relatively small finite value. | ||||||
| 92 | Electronic modulator for guidance systems | US509209 | 1974-09-25 | US3965443A | 1976-06-22 | Allistair Towle; Stanko Brcic |
| An amplitude modulation system having a modulation control circuit including a limiter for the modulation signal, a detector for deriving a DC contr0l signal from the unmodulated carrier, a first adjustable network connected to the detector to produce a signal applied to a modulation control circuit for adjusting depth of modulation, and an additional adjustable network connected between the detector and the modulator to produce a signal for adjusting the modulated carrier. | ||||||
| 93 | High efficiency rf power amplification with modulation signal controlled "on"-"off" switch varied amplifier dc potentials | US52938066 | 1966-02-23 | US3413570A | 1968-11-26 | BRUENE WARREN B; DENNIS JR TOM L; SCHOENIKE EDGAR O |
| 94 | Audio signal peak energy equalization | US80047659 | 1959-03-19 | US3060389A | 1962-10-23 | KAHN LEONARD R |
| 925,855. Transmission systems. L.R.KAHN. March 14, 1960 [March 19, 1959], No. 8987/60. Class 40 (4). A phase-distorting network 26 is used in a carrier wave transmission system to delay to different extents the different component frequencies of an unsymmetrical audio signal 22 from a source 20 without substantially affecting the intelligibility of the signal. The unsymmetrical signal 22 has high positive voltage peaks and low negative voltage peaks. The allpass network, Fig. 2, comprises two transformers 32, 34 and four lattice sections. The phase distortion tends to equalize the positive and negative excursion as in output signal 28 which is fed to a radio transmitter 10. In the network of Fig. 2, the component values of which are specified, frequencies less than 300 c/s. are delayed by delay times in the range 3 to 5 millisecs. Frequencies above 300 c/s. have delay times in the range 0 to 3 millisecs. The network may be designed to delay high frequencies by longer delay times than the low frequencies. | ||||||
| 95 | Ultra-high-frequency tuner | US80530459 | 1959-04-09 | US2995657A | 1961-08-08 | HERIBERT RUMMER |
| 96 | System for producing amplitudemodulated signals | US37721153 | 1953-08-28 | US2906970A | 1959-09-29 | WYLDE RONALD J |
| 97 | VERFAHREN UND VORRICHTUNG ZUR ERZEUGUNG EINES AMPLITUDEN-MODULIERTEN SIGNALS | EP08773534.6 | 2008-06-19 | EP2171838A2 | 2010-04-07 | SCHÖNINGER, Bernd |
| An improved method for producing an amplitude-modulated signal and an associated device are characterized substantially by the following characteristics, or an improved device for producing an amplitude-modulated signal comprises the following characteristics: the useful or information signal (101) is produced from a digitized useful or information signal (101), which is converted into an analog useful or information signal (1). A corrected analog useful or information signal (1k') is used for the useful or information signal (1) instead of a desired signal (1'), the corrected signal compared to the desired signal (1') being changed such that upper harmonics, which when using the desired signal (1') are outside the useful band (3) above the limit value for the signal size of the modulated carrier signal, when using the corrected useful or information signal (1k') are within the permitted range below the limit value for the signal size of the modulated carrier signal. | ||||||
| 98 | RETURN TO ZERO AND SAMPLING PULSE GENERATING CIRCUITS AND METHOD FOR DIRECT DIGITAL UP CONVERSION | EP03716815.0 | 2003-03-24 | EP1495540B1 | 2007-09-19 | KOMIAK, James J. |
| Direct up-conversion of a signal (10) is accomplished using a sampling pulse generator circuit (12, 16, 20, 24) and a gated differential amplifier 26, enabled by the sampling signal (25). When not enabled, the output of the differential amplifier (26) is pulled to zero. The sampling pulse (25) is generated from a base frequency sine wave (10) which is squared with a limiting amplifier (12), and further passed through one or more frequency doublers (16, 20) producing a times two signal (18), a times four signal (22) and so on. The squared base frequency 14 and frequency doubled signals (18, 22) are logically ORed (24) to produce a short duration pulse (25) which repeats at the frequency of the base signal. The resulting output (34) is an amplitude modulated pulse doublet time domain waveform. | ||||||
| 99 | VERFAHREN ZUR MODULATION EINES TRÄGERSIGNALS SOWIE VERFAHREN ZUR DEMODULATION EINES MODULIERTEN TRÄGERSIGNALS | EP04709199.6 | 2004-02-09 | EP1623497A1 | 2006-02-08 | HUBER, Klaus, University of Illinois |
| The invention relates to a novel method for modulating a carrier signal used for transmitting analog or digital message signals. The module k of elliptic functions is used as a modulation parameter instead of the amplitude or the frequency as in conventional amplitude and angle modulation methods. The carrier signal modulated according to the novel modulation method is thus provided with a constant amplitude and a fixed frequency while the signal form is chronologically modified at the rhythm of the message that is to be transmitted. | ||||||
| 100 | ENVELOPE MODULATOR FOR HAPTIC FEEDBACK DEVICES | EP02750399 | 2002-08-02 | EP1451648A4 | 2005-05-18 | TIERLING KOLLIN M |
| An amplitude modulator circuit 10 includes a reference oscillator 11 and an envelope modulator 12 coupled to the reference oscillator for receiving a reference signal. A microcontroller 14 is coupled to the envelope modulator for providing an envelope signal 13 to the envelope modulator and a low pass filter 15 is coupled to the envelope modulator for receiving a modulated command 16 from the envelope modulator. An inverter 17 is coupled to the low pass filter for receiving a low passed envelope modulated signal from the low pass filter and a transducer or amplifier 19 is coupled to the inverter and the low pass filter for receiving an inverted low passed signal and the low passed envelope modulated signal. | ||||||
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