en:sdrx
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en:sdrx [2013/07/26 09:27] – [Image frequency rejection] fluktuacia | en:sdrx [Unknown date] (current) – external edit (Unknown date) 127.0.0.1 | ||
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* [[http:// | * [[http:// | ||
* [[http:// | * [[http:// | ||
+ | * [[https:// | ||
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=== Image frequency rejection settings === | === Image frequency rejection settings === | ||
- | An interesting method involves the use of linearly modulated signal, that creates a " | + | An interesting method involves the use of linearly modulated signal, that creates a " |
==== Electromagnetic interference ==== | ==== Electromagnetic interference ==== | ||
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===== FAQ ===== | ===== FAQ ===== | ||
- | * Can I power the receiver with +/-10V? The signals on output reach amplitudes of the order of 10-100mV max. Why is than necessary to have such wide power supply range? | + | * Can I power the receiver with +/-10V? The signals on output reach amplitudes of the order of 10-100mV max. Why is than necessary to have such a wide power supply range? |
- | The wide power supply range is necessary, because as soon as a strong signal reaches NF band, it must not cause saturation | + | The wide power supply range is necessary, because as soon as a strong signal reaches NF band, it must not cause saturation |
- | * Why is there no integrated voltage | + | * Why is there no integrated voltage |
- | The stabiliser | + | The stabilizer |
* Do I have to power the receiver with +/-12V supply? Is the +/-10 not enough? | * Do I have to power the receiver with +/-12V supply? Is the +/-10 not enough? | ||
- | The receiver can be powered even with +/- 5V. If you're planing to use the receiver in a portable mode, we recommend the Li-ion batteries in pair for every branch, making the total power supply of +/- 7,4V, which should be sufficient for most applications outside | + | The receiver can be powered even with +/- 5V. If you're planing to use the receiver in a portable mode, we recommend the Li-ion batteries in pair for every branch, making the total power supply of +/- 7,4V, which should be sufficient for most applications outside the town (without strong signals). The accumulators in notebook batteries (of typical size 18650) are mostly suitable. The decreased capacity of old batteries does not matter, because the receiver' |
* Why does the receiver have I and Q output? Can I use the mono input of the sound card for signal digitization? | * Why does the receiver have I and Q output? Can I use the mono input of the sound card for signal digitization? | ||
- | The low-frequency signal from the receiver has I/Q format, so it can include the full input high-frequency signal data. It is basically a vector format, that can be demodulated in principle by any modulation with bandwidth lower than is the bandwidth of A/D conversion. [[http://cs.wikipedia.org/ | + | The low-frequency signal from the receiver has I/Q format, so it can include the full input high-frequency signal data. It is basically a vector format, that can be demodulated in principle by any modulation with bandwidth lower than is the bandwidth of A/D conversion. [[http://en.wikipedia.org/ |
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- | {{ : | + | {{ : |
The radioastronomy is quite perspective field for the deployment of this receiver and a large portion of research is currently devoted to it. | The radioastronomy is quite perspective field for the deployment of this receiver and a large portion of research is currently devoted to it. | ||
- | It's also good to point out, that amateur astronomers have a greater chance of success in the field of radio- than optic astronomy. In order to get results, radioastronomers need a lot of stations over a large area and that is easier to achieve for independent individuals than for organisation. | + | It's also good to point out, that amateur astronomers have a greater chance of success in the field of radio- than optic astronomy. In order to get results, radioastronomers need a lot of stations over a large area and that is easier to achieve for independent individuals than for organization. |
- | An example of project, that supports this notion is eg. [[http:// | + | An example of a project, that supports this notion is [[http:// |
===== Radio meteor detection stations ===== | ===== Radio meteor detection stations ===== | ||
- | The receiver is suitable for use in the radio meteor detection network, as is the case of several observatories in CR. [[http:// | + | The receiver is suitable for use in a radio meteor detection network, as is the case of several observatories in CR. [[http:// |
{{: | {{: | ||
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====== Ideas for improvements ====== | ====== Ideas for improvements ====== | ||
- | * <del> To add a logarithmic scalar output indicating "the extent | + | * <del> To add a logarithmic scalar output indicating "the extent of the receiver's saturation". </ |
- | * To add a module with a suitable ADC and so eliminate the complications with the funcioning | + | * To add a module with a suitable ADC and so eliminate the complications with the functioning |
- | * <del> To desing | + | * <del> To design a module with a galvanically separated symmetrical power supply. </ |
* To figure out a way to compare the gain between the individual receivers. (preferably digitally) | * To figure out a way to compare the gain between the individual receivers. (preferably digitally) | ||
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Adding more modules to the arrangement could create a complete set where the receiver would be independent on a computer. Its realisation has several variants: | Adding more modules to the arrangement could create a complete set where the receiver would be independent on a computer. Its realisation has several variants: | ||
- | * The receiver with a tunable oscillator and module with LDC that would show the tuned frequency. The buttons below the LCD would allow the retuning of the receiving frequency. | + | * The receiver with a tunable oscillator and a module with LDC that would show the tuned frequency. The buttons below the LCD would allow the retuning of the receiving frequency. |
- | * A second variant would be the same as the first one, with an exception of digitising | + | * A second variant would be the same as the first one, with an exception of digitizing |
====== UHF SDR SDRX02A receiver ====== | ====== UHF SDR SDRX02A receiver ====== | ||
- | **The design of the receiver described below is still only in preliminary stage of development** | + | **The design of the receiver described below is still only in a preliminary stage of development** |
- | The design should probably be even more modular. That includes separate VGA input amplifier, input band-pass filter, I/Q demodulator with input band-pass filter. | + | The design should probably be even more modular. That includes |
- | ACD with parallel anti-alias filter and FPGA with parallel USB interface. | + | ACD with a parallel anti-alias filter and FPGA with a parallel USB interface. |
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**The design of the receiver described below is still only in preliminary stage of development** | **The design of the receiver described below is still only in preliminary stage of development** | ||
- | The design should include separate input amplifier (VGA), input band-pass filter to limit the possible intermodulation, | + | The design should include |
- | Analog Frond End ADC with input anti-alias filter and FPGA with PCIe interface for connection to the thunderbolt module. | + | Analog Frond End ADC with input an anti-alias filter and FPGA with a PCIe interface for connection to the thunderbolt module. |
en/sdrx.1374830871.txt.gz · Last modified: 2013/07/26 09:27 (external edit)