Luis Cupido - Academia.edu (original) (raw)
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Universidad Nacional Experimental Romulo Gallegos
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Papers by Luis Cupido
Following a previous article where this circuit with a CPLD was used to implement a PLL scheme th... more Following a previous article where this circuit with a CPLD was used to implement a PLL scheme that could lock one VCXO to a 10MHz reference, this short article describes a different approach to the locking method, resulting in the possibility of locking only the least significant digits of any VCXO frequency making this circuit truly universal without need for specific configuration files as in the previous design.
Fusion Engineering and Design, 2002
The current paper presents a large memory giving special emphasis to the architecture and suitabi... more The current paper presents a large memory giving special emphasis to the architecture and suitability of the Linux OS for this type of applications. The system will be used on the joint european torus new correlation reflectometers composed by four microwave channels with four analogue signals each. All sixteen signals will be acquired by 12-bit VME fast acquisition channels at 2 Msamples/s achieving a total data rate of 60MB/s. Slower VME acquisition channels, with 16-bit resolution and sampling rates up to 250 ksamples/s, can also acquire these 16 signals. Two dedicated digital signal processors run an algorithm over this acquired data to avoid the use of the old KG8B root mean square analogue circuits as well as to control and to generate all the timing and acquisition clocks needed by the system.
In view of the more demanding measurements to be performed on next fusion devices a new generatio... more In view of the more demanding measurements to be performed on next fusion devices a new generation of reflectometer systems must be developed for both density profile and turbulence studies. The new generation reflectometry systems should be able to integrate sweeping and hopping capabilities and should also cope with complex broadband transmission lines and bistatic antenna arrangements. Signal purity and stability becomes a very important issue when the use of compensation networks such as delay lines become impossible. This is the scenario for reflectometry on ITER using ultra broadband frequency operation, bistatic antenna arrangements and long corrugated waveguide lines. The present paper describes a novel system for signal generation and detection (of both main plasma signal and local oscillator signals) capable of fast sweeping, frequency hopping as well as fixed frequency operation. It is based on a single synthesized source and utilizes several oscillators which are locked ...
Plasma Physics and Controlled Fusion, 2007
Review of Scientific Instruments, 2010
In broadband microwave reflectometry coherent detection is widely used to obtain the phase inform... more In broadband microwave reflectometry coherent detection is widely used to obtain the phase information and to improve the systems sensitivity, both in diagnostics measuring the electronic density profile and plasma fluctuations. Coherent detection uses a translated version of the probing signal to guarantee a stable Intermediate Frequency (IF). A novel technique to generate the frequency translation by double frequency conversion is here presented and its advantages over the commonly used single frequency conversion techniques employing image rejection mixers are discussed. The results obtained with the new frequency translator modules developed for three JET FM CW reflectometers, operating successfully at JET since mid 2009, are presented.
Following a previous article where this circuit with a CPLD was used to implement a PLL scheme th... more Following a previous article where this circuit with a CPLD was used to implement a PLL scheme that could lock one VCXO to a 10MHz reference, this short article describes a different approach to the locking method, resulting in the possibility of locking only the least significant digits of any VCXO frequency making this circuit truly universal without need for specific configuration files as in the previous design.
Fusion Engineering and Design, 2002
The current paper presents a large memory giving special emphasis to the architecture and suitabi... more The current paper presents a large memory giving special emphasis to the architecture and suitability of the Linux OS for this type of applications. The system will be used on the joint european torus new correlation reflectometers composed by four microwave channels with four analogue signals each. All sixteen signals will be acquired by 12-bit VME fast acquisition channels at 2 Msamples/s achieving a total data rate of 60MB/s. Slower VME acquisition channels, with 16-bit resolution and sampling rates up to 250 ksamples/s, can also acquire these 16 signals. Two dedicated digital signal processors run an algorithm over this acquired data to avoid the use of the old KG8B root mean square analogue circuits as well as to control and to generate all the timing and acquisition clocks needed by the system.
In view of the more demanding measurements to be performed on next fusion devices a new generatio... more In view of the more demanding measurements to be performed on next fusion devices a new generation of reflectometer systems must be developed for both density profile and turbulence studies. The new generation reflectometry systems should be able to integrate sweeping and hopping capabilities and should also cope with complex broadband transmission lines and bistatic antenna arrangements. Signal purity and stability becomes a very important issue when the use of compensation networks such as delay lines become impossible. This is the scenario for reflectometry on ITER using ultra broadband frequency operation, bistatic antenna arrangements and long corrugated waveguide lines. The present paper describes a novel system for signal generation and detection (of both main plasma signal and local oscillator signals) capable of fast sweeping, frequency hopping as well as fixed frequency operation. It is based on a single synthesized source and utilizes several oscillators which are locked ...
Plasma Physics and Controlled Fusion, 2007
Review of Scientific Instruments, 2010
In broadband microwave reflectometry coherent detection is widely used to obtain the phase inform... more In broadband microwave reflectometry coherent detection is widely used to obtain the phase information and to improve the systems sensitivity, both in diagnostics measuring the electronic density profile and plasma fluctuations. Coherent detection uses a translated version of the probing signal to guarantee a stable Intermediate Frequency (IF). A novel technique to generate the frequency translation by double frequency conversion is here presented and its advantages over the commonly used single frequency conversion techniques employing image rejection mixers are discussed. The results obtained with the new frequency translator modules developed for three JET FM CW reflectometers, operating successfully at JET since mid 2009, are presented.