Topic
Continuous phase modulation
About: Continuous phase modulation is a research topic. Over the lifetime, 3199 publications have been published within this topic receiving 37245 citations. The topic is also known as: CPM.
Papers published on a yearly basis
Papers
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01 Dec 1931TL;DR: In this paper, the fundamental mathematical expressions for amplitude, phase, and frequency modulation are derived in three different forms: as amplitude equations, side band equations and modulation vector equations, and the main results derived from a discussion of these equations are:
Abstract: This paper presents a comparative theoretical study of amplitude, phase, and frequency modulation. In the first part, the fundamental mathematical expressions for the three types of modulation are derived. They are expressed in three different forms: as amplitude equations, side band equations and modulation vector equations. The amplitude equations indicate the envelope of the radio-frequency directly. The side band equations refer to the number, amplitude, and phase of the side bands produced by modulation. In the modulation vector equations, corresponding side bands are combined in pairs to form a "modulation vector." This is a r-f magnitude, rotating with the angular velocity of the carrier and its amplitude is simultaneously being changed at an audio rate. The main results derived from a discussion of these equations are: In phase and frequency modulation an infinite number of side bands is produced. Amplitude modulation produces but one pair of side bands. In amplitude modulation the modulation vector, representing the first pair of side bands is in phase with the carrier. In phase and frequency modulation, it is 90 degrees out of phase with respect to the carrier. Frequency modulation is equivalent to a phase modulation in which the phase shift is inversely proportional to the audio frequency. By means of the modulation vector, a new vector diagram of the phase modulation is given. In the second part, amplitude modulation is considered in which undesired phase or frequency modulation or a combination of the two takes place simultaneously.
58 citations
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16 Mar 1999TL;DR: In this article, a coupler couples the first and second amplifiers to one another and to a load impedance, such that voltages or currents in the first amplifier become linearly related to voltages in the second amplifier.
Abstract: Two amplifiers that are driven using outphasing modulation are coupled to one another so that the amplifiers affect each other's effective load line. The two amplifiers can maintain efficiency over a wider dynamic range than in a conventional amplifier. Amplifiers according to the invention amplify an AC input signal of varying amplitude and varying phase using a DC power supply. A converter converts the AC input signal into a first signal having constant amplitude and a first phase angle and into a second signal having constant amplitude and a second phase angle. The first amplifier amplifies the first signal, and the second amplifier amplifies the second signal. A coupler couples the first and second amplifiers to one another and to a load impedance, such that voltages or currents in the first amplifier become linearly related to voltages or currents in the second amplifier. The coupler may include at least one transformer that serially couples the first and second amplifiers to one another and to the load impedance. The coupler may also include first and second quarter wave transmission lines that couple the first and second amplifiers to one another and to the load impedance. The amplifiers preferably use bilateral devices, such that current flows from the first and second amplifiers to the DC power supply during a part of a signal cycle, and thereby returns energy to the DC power supply. Each of the more than two signals of constant amplitude and controlled phase is then separately amplified in separate amplifiers. The separately amplified more than two signals of constant amplitude and controlled phase are then combined to produce an output signal that is an amplification of the input signal at the desired power level. When converting the input signal into more than two signals, the phase of each of the more than two signals of constant amplitude and controlled phase is controlled to produce the output signal that is an amplification of the input signal at the desired power level. According to another aspect, a signal of varying amplitude and varying phase is generated from a plurality of constant amplitude varying phase signals, the sum of which is the signal of varying amplitude and varying phase. An IQ waveform generator generates a cosine carrier modulation waveform I(t) and a sine carrier modulation waveform Q(t) from the signal of varying amplitude and varying phase. A function generator generates a complementary waveform Q'(t) from the cosine carrier modulation waveform I(t) such that the sum of squares of I(t) and Q'(t) is constant. A first modulator modulates a cosine carrier signal with I(t) to obtain a first modulated cosine carrier. A second modulator modulates a sine carrier signal with Q'(t) to obtain a first modulated sine carrier. A circuit such as a butterly circuit forms the sum and difference of the first modulated cosine carrier and the first modulated sine carrier to obtain the constant amplitude varying phase signals.
58 citations
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11 Oct 1992TL;DR: In this article, a modulation model is formed by estimating the instantaneous frequency and bandwidth using autoregressive spectrum analysis, which performed extremely well for input carrier-to-noise ratios as low as 15 dB.
Abstract: A modulation model representation of a signal is used to provide a convenient form for subsequent analysis. The modulation model is formed by estimating the instantaneous frequency and bandwidth using autoregressive spectrum analysis. In particular, the instantaneous bandwidth and derivative of the instantaneous frequency prove to be valuable parameters in estimating modulation type. This method performed extremely well for input carrier-to-noise ratios as low as 15 dB. Additionally, since the autoregressive fit to the frequency spectrum is second order, the autoregressive polynomials coefficients and corresponding roots can be computed with closed-form expressions. Thus, the method is computationally efficient. >
58 citations
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TL;DR: In this paper, a single bandpass microwave photonic filter (MPF) based on phase modulation and stimulated Brillouin scattering (SBS) was proposed and demonstrated, and the operation principle of the filter is based on the concept of using the Brillouins selective sideband amplification to achieve effective PM to amplitude modulation (AM) conversion.
Abstract: We propose and demonstrate a widely tunable single bandpass microwave photonic filter (MPF) based on phase modulation (PM) and stimulated Brillouin scattering (SBS). The operation principle of the filter is based on the concept of using the Brillouin selective sideband amplification to achieve effective PM to amplitude modulation (AM) conversion. Only when one of the phase modulated sidebands lies in the SBS gain spectrum, can PM-to-AM conversion occur and the corresponding PM frequency be detected. Whereas the phase modulated sidebands lie out of the SBS gain spectrum, there is no RF signal obtained due to the -phase difference. As a result, a bandpass filter centered at a special frequency can be achieved. By adjustment of the Brillouin pump wavelength, tunable single bandpass MPF can be obtained. In the experiment, a microwave photonic filter with narrow bandwidth of about 35 MHz and a tuning range of 20 GHz has been obtained.
58 citations
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TL;DR: In this article, a flux-quantizing A/D converter based on RSFQ elements, employing a novel front end capable of generating high-linearity multibit differential code within a wide dynamic range (up to 16 bits).
Abstract: We have developed a flux-quantizing A/D converter (ADC) based on RSFQ elements, employing a novel front end capable of generating high-linearity multibit differential code within a wide dynamic range (up to 16 bits). The front end operates as a phase modulator/demodulator and uses fractional-flux-quantum least significant bit (LSB). It runs at multi-GHz speed, enabling ADCs with large oversampling ratio and effective resolution in excess of 20 bits (after decimation filtering). We have designed, fabricated and tested several versions of a complete ADC using this new architecture and demonstrated its operation with dynamic range of 14 bits. We have also confirmed continuous phase modulation of the flux quantizer with a carrier frequency of 10 GHz. >
58 citations