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.

Signal Processing in Telecommunications with Forward Correction of Errors

Abstract: The development of mechanisms of increase efficiency of frequency-shift keying signals processing in telecommunications using algorithms of noise immunity channel coding in obstacle effect conditions is held in the article. The synthesis of the frequency-shift keying signal processing unit accounting intersymbol communication which is inherent for such signals with continuous phase is held. The conditions of the compromise implementation in the telecommunication information transmission channel with frequency shift keying and error correction coding for setting the optimal encoding rate in the range of the bandwidth of the information transmission system are explored. Linear cyclic codes Bose-Chaudhuri-Hocquenghem (BCH) are used for studying. By means of Matlab the article focuses on the definition of energetic benefit compared to uncoded system in case of equality of the bandwidth of the information transmission system with coding and without coding.

Phase detector and frequency demodulator including such a phase detector

Abstract: Phase detector having a first input for an angle-­modulated input carrier to be detected, and a second input for a reference carrier having a phase shift which is dependent on the angle modulation with respect to the input carrier, the input and reference carriers being at least multiplied in the phase detector, and a frequency demodulator including such a phase detector. In order to inhibit signal distortion and notably second-order interference products in the demodulation of an angle-modulated input carrier, the phase detector according to the invention is adapted to derive an in-­phase carrier A and a phase quadrature carrier B from the input carrier and to derive an in-phase carrier C and a phase quadrature carrier D from the reference carrier which has a phase which, at an average, is equal or opposite to that of the input carrier, while the phase detector is further adapted to supply from its output a signal which substantially corresponds to AC - BD.

Reduced state sequence detection of full response continuous phase modulation

Abstract: A reduced state sequence detector (RSSD) which combines decision feedback with Viterbi decoding is proposed for M-ary full response continuous phase modulation. The detector is analysed with minimum Euclidean distances and by simulations of the symbol error probability. It is shown that M-ary full response CPM schemes can be optimally decoded by a decoder with only two states when the modulation index is relatively small ( >

Image rejection in logic-based architecture for FSK modulation and demodulation

Abstract: A cost-effective continuous phase logic-based modulator and demodulator are provided to allow communications using binary frequency shift keying (BFSK) as well as M-ary FSK techniques The modulator of the 1-bit precision modem architecture is based on a 1-bit precision numerically controlled oscillator (NCO), which provides complete programmability with respect to a frequency of the 1-bit precision logic-based modulator and/or demodulator The 1-bit precision NCO includes an adder and a phase accumulator register which is clocked by a master clock signal A two-input multiplexer has a single bit symbol value to generate BFSK, or larger input multiplexers can be implemented to provide M-ary FSK The output of the 1-bit precision NCO is upconverted to an intermediate frequency using a simple logic function, ie, XNOR logic Alternatively, the intermediate frequency may be arrived at without the need for upconversion by directly utilizing a harmonic alias at a desired IF frequency The undesirable portion of the upconverted signal may be suppressed using I/Q image rejection, and/or an appropriate bandpass filter may be used A band limited, hard limited signal at the high IF is presented to the 1-bit precision demodulator as a receive IF signal, which is treated as a 1-bit quantization of the signal The receive IF signal is digitally down-converted to a low IF signal to produce an alias signal at the low IF frequency

Differential phase shift keying modulation system

Abstract: A differential phase shift keying modulating system is described, comprising two balanced modulators, one fed with a carrier frequency and the other fed with the carrier frequency phase shifted by 90 DEG . Modulating signals, respectively produced by a ring counter driving cosine and sine weighting circuits, are respectively fed to the two balanced modulators. Since the modulator signals have a sine/cosine relationship, the resultant output of the balanced modulators has a constant amplitude and a progressively increasing phase. Data is transmitted by causing the ring counter to count up or down, according to the value of data, so as to alter the direction of phase change of the output vector, and by varying the total number of stepping pulses applied to the counter during a given period, so as to vary the extent of the phase change during that period.