Based on the framework of Colpitts oscillator, a four-dimensional multi-scroll hyperchaotic system is proposed, which generates (2M+1)×(2N+1)-scroll chaotic and hyperchaotic attractors. The key strategy is to inc...Based on the framework of Colpitts oscillator, a four-dimensional multi-scroll hyperchaotic system is proposed, which generates (2M+1)×(2N+1)-scroll chaotic and hyperchaotic attractors. The key strategy is to increase the number of index-2 equilibrium points by introducing two unit saw-tooth functions to extend and modify the Colpitts oscillator model. By using bifurcation diagram and phase portrait, the dynamical characteristics of the multi-scroll hyperchaotic system are briefly studied. Moreover, micro-controller based circuit realization is introduced and the experimental results dem-onstrate that 7×5-scroll chaotic and hyperchaotic attractors can be obtained in the digital circuit.展开更多
By the aid of nullor-mirror models of the second-generation current-controlled conveyor(CCCII) and applying the nodal admittance matrix(NAM) expansion method, the family of current-mode Colpitts oscillators employing ...By the aid of nullor-mirror models of the second-generation current-controlled conveyor(CCCII) and applying the nodal admittance matrix(NAM) expansion method, the family of current-mode Colpitts oscillators employing four CCCIIs and three grounded capacitors is synthesized. Thirty-two Colpitts oscillators using CCCIIs are obtained in all. By using canonical number of components, the circuits can be easily integrated and the oscillation criterion and the oscillation frequency can be independently and electronically tuned by tuning bias currents of the CCCIIs. The paper-and-pencil analysis and Pspice simulation results have been included to support the synthesis method.展开更多
The design procedure of a CMOS process integrating Colpitts cr ystal oscillator is described in detail by using the tools of Matlab and advanced design system (ADS). The small-signal analysis is performed both in the ...The design procedure of a CMOS process integrating Colpitts cr ystal oscillator is described in detail by using the tools of Matlab and advanced design system (ADS). The small-signal analysis is performed both in the viewpoint of negative resistance and positive feedback. The analysis of condition for reliable start-up of oscillation and design guides for low phase noise is introduced. The measured phase noise is ?172dBc/Hz@10 kHz and the power dissipation is 0.36 mW at power supply 3V.展开更多
A 53 GHz Colpitts oscillator implemented in a SiGe：C BiCMOS technology is presented. Limited by a 26.5 GHz frequency analyzer, the oscillator was measured indirectly through an on-chip mixer. The mixer downconverted ...A 53 GHz Colpitts oscillator implemented in a SiGe：C BiCMOS technology is presented. Limited by a 26.5 GHz frequency analyzer, the oscillator was measured indirectly through an on-chip mixer. The mixer downconverted the oscillating frequency to an intermediate frequency （IF） below 26.5 GHz. By adjusting the local oscillating （LO） frequency and recording the changes of IF frequency, the oscillator＇s output frequency （RF） was determined. Additionally, using phase noise theory of mixers, the oscillator＇s phase noise was estimated as -58 dBc/Hz at 1 MHz offset and the output power was about -21 dBm. The chip is 270 ×480μm in size.展开更多
A Colpitts oscillator, working around a 3 GHz frequency, contains a double gate Metal Oxide Semiconductor transistor (DGMOS). A mixed-mode analysis is involved, applying a quantum model to the device, whereas the rest...A Colpitts oscillator, working around a 3 GHz frequency, contains a double gate Metal Oxide Semiconductor transistor (DGMOS). A mixed-mode analysis is involved, applying a quantum model to the device, whereas the rest of the considered circuit is governed by Kirchhoff’s laws. The Linear Time Variant (LTV) model of phase noise is based on the Impulse Sensitivity Function of the Colpitts Oscillator which describes carefully the sensitivity of an oscillator to any impulse current injection in any node of the circuit. Finally, we improve the phase noise modeling, confronting some analytical developments to mixed-mode simulations.展开更多
In this work, we suggest a system for chaos-based encryption of electrocardiographic signals. It uses simple electronics organized around a colpitts chaotic oscillator. The system has been designed, implemented and te...In this work, we suggest a system for chaos-based encryption of electrocardiographic signals. It uses simple electronics organized around a colpitts chaotic oscillator. The system has been designed, implemented and tested. The encrypted signal has been decrypted and compared to the original ECG signal. Experimental results were analysed and proved encouraging.展开更多
A novel digital secure communication system employing dual synchronization of chaos in two pairs of Colpitts circuits is proposed. The binary information to be transmitted is firstly modulated by digital modulation sc...A novel digital secure communication system employing dual synchronization of chaos in two pairs of Colpitts circuits is proposed. The binary information to be transmitted is firstly modulated by digital modulation scheme, and then mixed together with two chaotic waveforms generated by two Colpitts circuits with different circuit parameters. Thus the combined （and encrypted） signal is transmitted through an additive white Gauss noise （AWGN） channel. In the receiver, the binary message can he recovered only when the parameters of the two Colpitts circuits are known. If the parameters of the two Colpitts circuits are owned by two different users, this can be viewed as a （2,2） threshold scheme. Based on large amount of simulations, the bit error rate （BER） performance of this communication scheme is presented.展开更多
Chaotic Colpitts circuits with fundamental frequency f* beyond 1GHz are studied by both circuit simulation and experiment using Philips' broadband transistor with threshold frequency of 25GHz. For the basic config...Chaotic Colpitts circuits with fundamental frequency f* beyond 1GHz are studied by both circuit simulation and experiment using Philips' broadband transistor with threshold frequency of 25GHz. For the basic configuration of Colpitts circuit with f* of about 1.6GHz, broadband continuous power spectra could be obtained from both circuit simulations and experiments. The harmonics of the observed signal from Agilent PSA/ESA spectrum analyzer are as noticeable as far as 12GHz. A modified Colpitts circuit structure employing the parasitic inductance of BJT (Bipolar Junction Transistor) is also proposed and investigated. By circuit simulation, chaotic attractor and broadband continuous power spectra could be obtained from the modified Colpitts circuit with f* of about 3.5GHz. Because the parasitic effects of the prototype board, the experiment result of the modified Colpitts circuit does not agree well with the simulation result. The gap between the simulation and experimental result could be bridged by replacing the lumped circuit elements with distributed ones.展开更多
基金Supported by the Natural Science Foundations of Jiangsu Province (No. BK2009105)
文摘Based on the framework of Colpitts oscillator, a four-dimensional multi-scroll hyperchaotic system is proposed, which generates (2M+1)×(2N+1)-scroll chaotic and hyperchaotic attractors. The key strategy is to increase the number of index-2 equilibrium points by introducing two unit saw-tooth functions to extend and modify the Colpitts oscillator model. By using bifurcation diagram and phase portrait, the dynamical characteristics of the multi-scroll hyperchaotic system are briefly studied. Moreover, micro-controller based circuit realization is introduced and the experimental results dem-onstrate that 7×5-scroll chaotic and hyperchaotic attractors can be obtained in the digital circuit.
基金Supported by the Shaanxi Provincial Key Research and Development Program,China(2018NY-158)
文摘By the aid of nullor-mirror models of the second-generation current-controlled conveyor(CCCII) and applying the nodal admittance matrix(NAM) expansion method, the family of current-mode Colpitts oscillators employing four CCCIIs and three grounded capacitors is synthesized. Thirty-two Colpitts oscillators using CCCIIs are obtained in all. By using canonical number of components, the circuits can be easily integrated and the oscillation criterion and the oscillation frequency can be independently and electronically tuned by tuning bias currents of the CCCIIs. The paper-and-pencil analysis and Pspice simulation results have been included to support the synthesis method.
文摘The design procedure of a CMOS process integrating Colpitts cr ystal oscillator is described in detail by using the tools of Matlab and advanced design system (ADS). The small-signal analysis is performed both in the viewpoint of negative resistance and positive feedback. The analysis of condition for reliable start-up of oscillation and design guides for low phase noise is introduced. The measured phase noise is ?172dBc/Hz@10 kHz and the power dissipation is 0.36 mW at power supply 3V.
文摘A 53 GHz Colpitts oscillator implemented in a SiGe：C BiCMOS technology is presented. Limited by a 26.5 GHz frequency analyzer, the oscillator was measured indirectly through an on-chip mixer. The mixer downconverted the oscillating frequency to an intermediate frequency （IF） below 26.5 GHz. By adjusting the local oscillating （LO） frequency and recording the changes of IF frequency, the oscillator＇s output frequency （RF） was determined. Additionally, using phase noise theory of mixers, the oscillator＇s phase noise was estimated as -58 dBc/Hz at 1 MHz offset and the output power was about -21 dBm. The chip is 270 ×480μm in size.
文摘A Colpitts oscillator, working around a 3 GHz frequency, contains a double gate Metal Oxide Semiconductor transistor (DGMOS). A mixed-mode analysis is involved, applying a quantum model to the device, whereas the rest of the considered circuit is governed by Kirchhoff’s laws. The Linear Time Variant (LTV) model of phase noise is based on the Impulse Sensitivity Function of the Colpitts Oscillator which describes carefully the sensitivity of an oscillator to any impulse current injection in any node of the circuit. Finally, we improve the phase noise modeling, confronting some analytical developments to mixed-mode simulations.
文摘In this work, we suggest a system for chaos-based encryption of electrocardiographic signals. It uses simple electronics organized around a colpitts chaotic oscillator. The system has been designed, implemented and tested. The encrypted signal has been decrypted and compared to the original ECG signal. Experimental results were analysed and proved encouraging.
文摘A novel digital secure communication system employing dual synchronization of chaos in two pairs of Colpitts circuits is proposed. The binary information to be transmitted is firstly modulated by digital modulation scheme, and then mixed together with two chaotic waveforms generated by two Colpitts circuits with different circuit parameters. Thus the combined （and encrypted） signal is transmitted through an additive white Gauss noise （AWGN） channel. In the receiver, the binary message can he recovered only when the parameters of the two Colpitts circuits are known. If the parameters of the two Colpitts circuits are owned by two different users, this can be viewed as a （2,2） threshold scheme. Based on large amount of simulations, the bit error rate （BER） performance of this communication scheme is presented.
基金Supported by the National Natural Science Foundation of China (No.60201001).
文摘Chaotic Colpitts circuits with fundamental frequency f* beyond 1GHz are studied by both circuit simulation and experiment using Philips' broadband transistor with threshold frequency of 25GHz. For the basic configuration of Colpitts circuit with f* of about 1.6GHz, broadband continuous power spectra could be obtained from both circuit simulations and experiments. The harmonics of the observed signal from Agilent PSA/ESA spectrum analyzer are as noticeable as far as 12GHz. A modified Colpitts circuit structure employing the parasitic inductance of BJT (Bipolar Junction Transistor) is also proposed and investigated. By circuit simulation, chaotic attractor and broadband continuous power spectra could be obtained from the modified Colpitts circuit with f* of about 3.5GHz. Because the parasitic effects of the prototype board, the experiment result of the modified Colpitts circuit does not agree well with the simulation result. The gap between the simulation and experimental result could be bridged by replacing the lumped circuit elements with distributed ones.
