| 序号 | 专利名 | 申请号 | 申请日 | 公开（公告）号 | 公开（公告）日 | 发明人 |
|---|---|---|---|---|---|---|
| 21 | Use of low pass filter and equalizer for noise reduction in direct up-conversion schemes | US721786 | 1996-09-25 | US5896421A | 1999-04-20 | Hassan Zamat; Kumud S. Patel; Brian K. Fair |
| A transmitter in a base transceiver station in a wireless telephony network uses a direct up-conversion scheme to convert an input signal with in-phase and quadrature phase (I, Q) components to a radio frequency within a transmit band. A low-pass filter filters noise from the input signal components and a phase equalizer equalizes the phase distortions caused by the filtering in the input signal components. The signal components are then provided to an up-converter, such as a quadrature modulator, for conversion to a radio frequency signal within a transmit band. The transmitter of the present invention complies with the TIA'S 15-54 emission requirements.r connected to the first low pass filter and a second phase equalizer connected to the second low pass filter. | ||||||
| 22 | Wideband IQ modulator with RC/CR automatic quadrature network | US550546 | 1995-11-07 | US5694093A | 1997-12-02 | Marcus K. DaSilva; Andrew M. Teetzel |
| An IQ modulator incorporates a quadrature network that is responsive to a frequency dependent control signal and that has in-phase and quadrature signals that are of equal amplitude and in exact quadrature over a wide range of applied frequencies. The quadrature network includes RC and CR phase shifters whose C's are fixed capacitors of equal value and whose R's are made equal to each other and to the capacitive reactance of the C's by the action of the frequency dependent control signal. The R's may be FET's. The frequency dependent control signal may be generated without express knowledge of the applied frequency by a servo loop that nulls out the amplitude difference between the in-phase and quadrature outputs from the quadrature network; it may also be generated from a look-up table as an express function of frequency. The frequency dependent control signal is split into separate instances that are applied to each R, and an offset may be introduced therebetween to provide extreme precision. The offset may be fixed or programmatically controlled as a function of frequency. Varactors may be used to provide variable C's in cooperation with fixed R's. The entire circuit may be fabricated as a GaAs IC for use in the frequency range of 200 MHz to 3GHz. | ||||||
| 23 | RC/CR automatic quadrature network | US542745 | 1995-10-13 | US5644260A | 1997-07-01 | Marcus K. DaSilva; Andrew M. Teetzel |
| An IQ modulator incorporates a quadrature network that is responsive to a frequency dependent control signal and that has in-phase and quadrature signals that are of equal amplitude and in exact quadrature over a wide range of applied frequencies. The quadrature network includes RC and CR phase shifters whose C's are fixed capacitors of equal value and whose R's are made equal to each other and to the capacitive reactance of the C's by the action of the frequency dependent control signal. The R's may be FET's. The frequency dependent control signal may be generated without express knowledge of the applied frequency by a servo loop that nulls out the amplitude difference between the in-phase and quadrature outputs from the quadrature network; it may also be generated from a look-up table as an express function of frequency. The frequency dependent control signal is split into separate instances that are applied to each R, and an offset may be introduced therebetween to provide extreme precision. The offset may be fixed or programmatically controlled as a function of frequency. Varactors may be used to provide variable C's in cooperation with fixed R's. The entire circuit may be fabricated as a GaAs IC for use in the frequency range of 200 MHz to 3 GHz. | ||||||
| 24 | In-phase combiner and RF recovery system | US977044 | 1992-11-16 | US5304943A | 1994-04-19 | Floyd A. Koontz |
| A system and method for combining RF signals by a series of in-phase combiners. The system uses a series of switched, high efficiency amplifiers which may be selectively operated to obtain a desired output signal, such as an Amplitude Modulated (AM) signal. The output signals of the amplifiers are combined by a series of in-phase combiners. In a high linearity system a feedback loop is used to correct for combiner losses. The RF power normally lost in the combiners is recovered and available to increase the overall combiner efficiency. | ||||||
| 25 | Amplitude modulation apparatus and method | US444460 | 1982-11-24 | US4499339A | 1985-02-12 | Gordon L. Richard |
| An apparatus and a method modulate a carrier signal so that the resultant modulated signal varies between a value substantially equal to the quiescent level of the carrier signal and peak values up to several hundred percent of the quiescent level of the carrier signal. The apparatus includes an electrical circuit for adjusting the modulating signal so that it is clamped at a reference value to prevent overmodulation. The clamped signal controls a variable resistance mechanism which forms a part of the gain determining portion of a modulator circuit including an amplifier. The amplifier modulates the carrier signal in accordance with the gain determined by the variable resistance. The variable resistance is controlled by the clamped signal so that it causes the gain of the amplifier circuit to vary between approximately one and a value greater than one. So that the apparatus can be used by a person having a hearing impediment wherein the dynamic range detectable by the user is less than the dynamic range detectable by a normal ear, the apparatus also includes a circuit which compresses a detected acoustical signal which is within a first dynamic range into an electrical modulating signal within a dynamic range which is smaller than the first dynamic range and which is within the dynamic range perceivable by the user of the apparatus. | ||||||
| 26 | Automatic shutdown arrangement for stand-alone television modulator | US010485 | 1979-02-08 | US4286336A | 1981-08-25 | Robert F. Sanford |
| A carrier generator and modulator has a modulating signal input terminal to which video may be applied from a television camera, a video game or a computer for modulating a carrier on a standard television channel, for producing a visual display of the modulating signal on a standard television receiver. In home applications, there is little control over the maximum amplitude of the video signal which may be applied to the video input. This may allow over-modulation and the production of high-frequency distortion and harmonic signals having excessive amplitude, which may be coupled from the modulator, find their way to and interfere with other standard receivers. An automatic shutdown circuit includes a comparator, the input of which is coupled to the modulating signal input terminal. The comparator removes energizing potential from at least a portion of the carrier generator and modulator in the event that the amplitude of the modulating signal input exceeds a predetermined limit. The carrier generator and modulator is thereby disabled at a modulating signal amplitude less than that at which unwanted distortion occurs. | ||||||
| 27 | Amplitude modulation circuit for a transmitter | US886661 | 1978-03-14 | US4225822A | 1980-09-30 | Keiichiro Kariatsumari |
| An amplitude modulation circuit for a transmitter has an automatic level controlled circuit (ALC circuit), including in its negative feedback loop a series circuit of a high-pass filter, a rectifier circuit and an eliminator circuit, for modulation degree suppression, thereby avoiding overmodulation. The high-pass filter is so designed that the negative feedback signal level for modulation degree suppression of the ALC circuit is raised as the audio-signal frequency supplied to the transmitter increases. In the modulation circuit having such ALC circuit, a sufficiently high mean modulation degree may be obtained without encountering overmodulation if the main spectrum components of the input audio-frequency signal are distributed in the intermediate range of the audio-signal frequency band. On the other hand, if the main spectrum components of the audio-frequency signal are distributed in the higher (high-pass) range, the upper limit of the modulation degree is restricted to a moderately lower value so as to reduce production of spurious signals. Here the ALC circuit operates so as not to change the frequency characteristic of the audio-frequency input signal but to suppress the modulation degree uniformly throughout the frequency band of the audio-frequency input signal. Therefore, the modulation circuit does not cause variation in a tone quality of the input signal. | ||||||
| 28 | Radio transmitter automatic volume control | US49113943 | 1943-06-17 | US2426193A | 1947-08-26 | FERNSLER GEORGE L |
| 29 | Oscillation modulator | US47627643 | 1943-02-18 | US2345712A | 1944-04-04 | MOHR MILTON E |
| 30 | 다중변조 및 시분할 전송기술을 이용한 단파 표준시 전송장치, 전송방법, 전송시스템 및 그 기록매체 | KR1020120115367 | 2012-10-17 | KR1020140049286A | 2014-04-25 | 양성훈; 이창복; 권택용; 이영규 |
| Disclosed are a device, a method and a system for transmitting a single wave standard time using a multi-modulation and a time division transmitting technology, and a recording medium thereof. More specifically, the device for transmitting a single wave standard time comprises a time code generator for generating a time code; an AM modulator for receiving the time code generated in the time code generator to be modulated to an AM signal; an FSK modulator for receiving the time code generated in the time code generator to be modulated to an FSK signal; a selection means for selecting the AM signal generated in the AM modulator or the FSK signal generated in the FSK modulator; a reference frequency input device for applying a single wave signal to the time code generator, the AM modulator and the FSK modulator; and a transmitter for transmitting the AM signal or the FSK signal selected by the selection means. Therefore, the device for transmitting a single wave standard time using a multi-modulation and a time division transmitting technology enables a receiver to selectively receive the time code by the FSK according to the receiving environment while protecting the existing AM user. [Reference numerals] (10) First time code generator; (12) Second time code generator; (20) AM modulator; (30) FSK modulator; (40) Reference frequency input device; (60) Time division controller; (70) Transmitter | ||||||
| 31 | 라디오 송신기 변조 제어회로 | KR1019820002307 | 1982-05-25 | KR1019840000116A | 1984-01-30 | 폴죤웨버 |
| 내용없음 | ||||||
| 32 | 送信機用の合成部及びデジタル振幅変調装置 | JP2013092732 | 2013-04-25 | JP2014216848A | 2014-11-17 | TAKAHASHI YOSHIHIKO; FUNAHASHI YUKI |
| 【課題】トランスの巻線数を容易に変更可能で、自由度が高く作業性を向上し得る。【解決手段】実施形態によれば、送信機用の合成部は、複数の増幅器それぞれに接続されるトランスの1次側巻線と、トランスの1次側巻線に対向するトランスの2次側巻線とからなる送信機用の合成部を対象とし、複数のコア支持ユニットと、固定体とを備えるようにしたものである。複数のコア支持ユニットは、1次側巻線が巻かれたトロイダル型コアを支持する支持板と、トロイダル型コアを支持板に固定する固定手段と、トロイダル型コアの内部、または、トロイダル型コアの周囲のいずれか一方に、2次側巻線を挿通する挿通部とを有する。固定体は、複数のコア支持ユニットがそれぞれ着脱可能に取り付けられ、複数のコア支持ユニットを積み重ねる方向に沿って形成される複数の受部を有する。【選択図】図4 | ||||||
| 33 | Parusuhenchojidoseigyosochi | JP6072781 | 1981-04-23 | JPH0247710B2 | 1990-10-22 | JIUSETSUPE BERUTOTSUCHI |
| 34 | Modulating circuit | JP8274383 | 1983-05-13 | JPS59208908A | 1984-11-27 | KADOKAWA SHIGERU; MAMETA JIYUNICHI |
| PURPOSE:To prevent previously the cuoff of a carrier wave signal for an amplitude modulating circuit which is suitably used when the reproduction signal of a magnetic video recording/reproducing device is supplied to a TV receiver, by controlling the modulation factor after detecting the variance of the input signal which is supplied to a modulating circuit. CONSTITUTION:When a reproduction signal VIN is lowered less than the reference voltage V2, an overmodulation preventing circuit 11 is actuated to turn off transistors Q4 and Q6. Then a current I2 is flowed from a +VCC power supply via a TRQ5 and a resistance R6. Then a TRQ7 is turned on by the voltage V2, and therefore a current route of a current I3 is formed from the +VCC power supply via a TRQ8 or Q9 and TRsQ7 and Q2. In this case, I2<I3 is satisfied. When the signal VIN is reduced less than the V2, the current I3 flows to a load resistance RL. Thus the voltage drop of the load RL is set at I3.RL which is larger than I2.RL. Therefore an output signal VOUT is slightly less than the highest level while the signal VIN is lower than the V2. In other words, the cutoff of a carrier wave signal fv is prevented by flowing forcibly the current I3. | ||||||
| 35 | Controller of modulation degree | JP19197381 | 1981-11-30 | JPS5894208A | 1983-06-04 | SUGIYAMA YUKIO |
| PURPOSE:To keep a prescribed modulation degree to the change of load, by detecting the carrier signal level and the low frequency signal level from the modulated wave signal of output and applying feedback after comparing both levels with each other. CONSTITUTION:The carrier signal supplied from an oscillator (not shown in figure) is fed to a modulation amplifying circuit 8 after high frequency amplification 7. While the low frequency signal is fed to the circuit 8 after low frequency amplification 10. The carrier signal is modulated with the low frequency signal through the circuit 8 and amplified again to be delivered in the form of the modulated wave signal. This modulated wave signal is fed to an extracting circuit 11 for carrier signal component and to an extracting circuit 12 for low frequency signal component. Thus the carrier signal component obtained with no modulation given by the low frequency signal is extracted out of the circuit 11, and the rectified 13 carrier signal level A is fed to a voltage comparator 15. At the same time, the low-frequency signal component is extracted out of the circuit 12, and the low frequency signal level B is fed to the circuit 15. The circuit 12 performs the relative voltage comparison between the signal levels A and B and then applies feedback. | ||||||
| 36 | Amplitude modulating circuit | JP3986380 | 1980-03-28 | JPS56137712A | 1981-10-27 | OOTSUKI TSUGUO; MUROZAKI MIKIO |
| PURPOSE:To prevent an output-side amplifier from being overloaded with a switching voltage depending upon a carrier, by applying out-of-phase switching voltages, developed by the same carrier input, to the collector of the transistor of a modulator. CONSTITUTION:A modulator having its output-side transformer substituted by a transistor is provided with the circuit consisting of transistor TR5, resistance VR1, transformer T11, transistor TR6, resistance VR2, and transformer T21. Through those circuits, voltages reverse in phase to and equal in amplitude to collector voltages of transistors TR1 and TR2 are developed at points (c) and (b) and collector currents of TR1 and TR2 are supplied from T11 and T21, so that no voltage by a carrier is developed at the collectors. Further, adjusting resistances VR1 and VR2 minimizes the generation of the voltage, and the leakage of a carrier to the output can be reduced. | ||||||
| 37 | Extraction system for envelope signal of wave to be modulated in amplitude modulation | JP13190579 | 1979-10-15 | JPS5656007A | 1981-05-16 | NAKAMURA SHIYOUZOU |
| PURPOSE:To obtain unipolar envelope signals that are equal or nearly equal in phase and amplitude, by obtaining two 90 deg. or approximately 90 deg. out-of-phase squared-wave signals, equivalent to squared values of respective instantaneous values of amplitude of wave to be modulated, from a wave to be modulated. CONSTITUTION:A wave to be moldulated applied to input terminal 1 is processed by squared-wave generating circuit 2 for an n-degree phase-shift signal and squared- wave generating circuit 3 for an (n+90)-degree phase-shift signal, so that both the circuits will output two 90 deg. out-of-phase squared-wave signals equivalent to squared values of respective instantaneous values of the amplitude of the wave to be modulated. Those signals are applied to adding circuit 4 and through the squaring arithmetic of squaring circuit 5, a unipolar envelope signal that coincides in phase and amplitude with the envelope of the input wave to be modulated appears at output terminal 6 when the absolute value of (n) is small. When the absolute value of (n) is large, on the other hand, a unipolar envelope signal coinciding in phase and amplitude with the envelope of the wave to be modulated phase-shifted by (n) degree can be obtained. | ||||||
| 38 | Amplitude modulation circuit | JP1242579 | 1979-02-06 | JPS55104138A | 1980-08-09 | YOSHIKAWA YOSHIKAZU; NISHIMURA TOSHIYUKI; TSUDA YUUJI |
| PURPOSE:To prevent the interference to the radio unit in the vicinity, by preventing the spread of the carrier frequency spectrum with amplitude modulation, through the provision of the delay circuit taking longer the leading and trailing time of rectangular waves and through the intermission of carrier with the output of delay circuit. CONSTITUTION:When the transistor 21 of the delay circuit IV taking longer the leading and trailing of the rectangular waves of the rectangular wave osicllation circuit V is ON, electromagnetic waves are radiated since miximum carrier current flows to the bar antenna coil 6 of the carrier power amplifying circuit II. When the transistor 21 is OFF, the transistor 9 is OFF, no current flows to the bar antenna coil 6 and no electromagnetic waves are radiated. Since the leading and trailing of the amplitude modulation signal constitute exponential curve having the time constant of the (resistor 23)X(capacitor) 22 of the delay circuit IV, the harmonics included in the amplitude modulation signal is less and the giving of electromagnetic wave interference is less. | ||||||
| 39 | Dispersive radio transmission device | JP11124778 | 1978-09-12 | JPS5538737A | 1980-03-18 | USHIYAMA KATSUMI; KIOGAWA TAKAO |
| PURPOSE:To facilitate elimination of the beat frequency component caused at the reception side and thus to prevent the loss of the signal component by controlling the transmission frequency of each dispersive transmitter via the reference frequency of the main unit. CONSTITUTION:Frequency fO of crystal oscillator 1 of main unit 7 is divided via divider 2 down to low frequency (reference frequency) fS outside the sound formation band and then compounded with aural signal fi through compounding unit 4 to be transmitted to dispersive transmitter 20 via cable 8. Transmitter 20 contains the loop circuit comprising crystal oscillator 13 featuring frequency f' nearly equal to fO, divider 14 of output frequency f'S BPF15, phase discriminator 11 which delivers the DC component proportional to the phase difference between frequencies fS and f'S, and variable capacitor 12 which controls frequency f' by the output of discriminator 11. Then frequency f' is applied to modulator 11 with the phase modulation given with signal fi of BPF17 and then transmitted through antenna 21. | ||||||
| 40 | Modulator | JP3158277 | 1977-03-24 | JPS53117363A | 1978-10-13 | KASHIYUU KEIICHIROU |
| PURPOSE: From the signal obtained via high-pass filter, an automatic amplitude control signal is formed to limit the modulation degree against the input signal with a high and wide frequency band or at a controlling level, thereby suppressing the generation of spurious. COPYRIGHT: (C)1978,JPO&Japio | ||||||
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