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--- en:sdrx [2013/07/26 09:24] – [Optical Ethernet] fluktuacia
+++ en:sdrx [Unknown date] (current) – external edit (Unknown date) 127.0.0.1
@@ Line 169: / Line 169: @@
   * [[http://www.sm5bsz.com/linuxdsp/linrad.htm|Linrad]] - A Linux SDR receiving tool, that contains some of the more advenced functions (that are not included in HDSDR) like mirror signal rejection in various bands
   * [[http://www.qsl.net/d/dl4yhf/spectra1.html|Spectrum Lab]] - a utility for a various signal processing in the audible band. We mostly us it for [[http://wiki.meteory.sk/doku.php?id=cs:radio_navod|meteor detection]].
+  * [[https://github.com/MLAB-project/pysdr|pySDR]] - Our OpenGL powered waterfall software.
@@ Line 245: / Line 246: @@
 The MDS of -120dbm on 150MHz.
-Towards the lower frequencies it increases, toward higher it decreases.
+Towards the lower frequencies it increases, toward the higher it decreases.
 ==== Image frequency rejection ====
-The minimal and easily achievable is the image frequency rejection of 50dB on 150MHz RF in. The usual maximum limit is 70dB (higher values depend on the particular receiver).
+The minimal and easily achievable image frequency rejection is of 50dB on 150MHz RF in. The usual maximum limit is 70dB (higher values depend on the particular receiver).
 The image frequency rejection must be trimmed for each band separately, since it depends on detuning of the phase of mixer switching and for different frequencies the detuning can vary.
-The effect of the temperature on settings is not extensive and so it is possible to create a correction table for all operating bands. Some software tools (like Linarad) are able to create such table automatically after the calibration is running and proper generator is connected to the receiver's input.
+The effect of a temperature on settings is not extensive and so it is possible to create a correction table for all operating bands. Some software tools (like Linarad) are able to create such table automatically after the calibration is running and proper generator is connected to the receiver's input.
 === Image frequency rejection settings ===
-An interesting method involves the use of linearly modulated signal, that creates a "intensity block" in the spectrum, that is than possible to trim to the minimum. Such signal can be obtained for example through FM modulation of the generator output. We've learned about this method form OK1VAW.
+An interesting method involves the use of linearly modulated signal, that creates a "intensity block" in the spectrum, that is than possible to be trimmed to the minimum. Such signal can be obtained for example through FM modulation of the generator output. We've learned about this method form OK1VAW.
 ==== Electromagnetic interference ====
@@ Line 271: / Line 272: @@
 ===== 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 of any part of the receiver. The signal would otherwise spread to the whole output band and so it's necessary to use high dynamic range even for generally weak signals.
+The wide power supply range is necessary, because as soon as a strong signal reaches NF band, it must not cause saturation in any part of the receiver. The signal would otherwise spread to the whole output band and so it's necessary to use high dynamic range even for generally weak signals.
-  * Why is there no integrated voltage stabiliser? This kind of power supply makes its the use of the receive more complicated.
+  * Why is there no integrated voltage stabilizer? This kind of power supply makes it more complicated.
-The stabiliser is missing on purpose, so that in the case of connecting more receivers (interferometry, radioastronomy) all would have the same power supply and thus the same drift.
+The stabilizer is missing on purpose, so that in the case of connecting more receivers (interferometry, radioastronomy) all would have the same power supply and thus the same drift.
   * 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 of 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's power consumption is low.
+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's power consumption is low.
   * 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/wiki/Konstela%C4%8Dn%C3%AD_diagram|A more thorough explanation of the I/Q problem.]]
+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/wiki/Constellation_diagram|A more thorough explanation of the I/Q problem.]]
@@ Line 300: / Line 301: @@
-{{ :cs:sdr:radioasronomy_configuration.png?300 |A configuration suitable for phase processing of the signals coming from more antennae}}
+{{ :cs:sdr:radioasronomy_configuration.png?300 |A configuration suitable for a phase processing of signals coming from more antennae}}
 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://www.lofar.org/|LOFAR]].
+An example of a project, that supports this notion is [[http://www.lofar.org/|LOFAR]].
 ===== 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://www.astrozor.cz/index.php|The map of observation points.]] The receiver than works as a part of a radar.
+The receiver is suitable for use in a radio meteor detection network, as is the case of several observatories in CR.  [[http://www.astrozor.cz/index.php|The map of observation points.]] The receiver works here as a part of a radar.
 {{:cs:designs:metor_shower.jpg?200|}}
@@ Line 333: / Line 334: @@
 ====== Ideas for improvements ======
-  * <del> To add a logarithmic scalar output indicating "the extent of saturation of the receiver". </del> The logarithmic detector for measuring of the integral output through the input band of the receiver. (Possibly can be done with RF detector [[en:rfdetect|RFdetect01A]]).
+  * <del> To add a logarithmic scalar output indicating "the extent of the receiver's saturation". </del> The logarithmic detector for measuring of the integral output through the input band of the receiver. (Possibly can be done with RF detector [[en:rfdetect|RFdetect01A]]).
-  * To add a module with a suitable ADC and so eliminate the complications with the funcioning of the suitable sound card.
+  * To add a module with a suitable ADC and so eliminate the complications with the functioning of the suitable sound card.
-  * <del> To desing module with a galvanically separated symmetrical power supply. </del> Solved by [[cs:sympower|SYMPOWER01A]]  module.
+  * <del> To design a module with a galvanically separated symmetrical power supply. </del> Solved by [[cs:sympower|SYMPOWER01A]]  module.
   * To figure out a way to compare the gain between the individual receivers. (preferably digitally)
@@ Line 343: / Line 344: @@
 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 the analog output, that would be transmitted through some kind of a common interface to a computer (USB, ThunderBolt, Ethernet, ...). The same interface could be used for LO tuning as well.
+  * A second variant would be the same as the first one, with an exception of digitizing the analog output, that would be transmitted through some kind of a common interface to a computer (USB, ThunderBolt, Ethernet, ...). The same interface could be used for LO tuning as well.
 ====== 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 a separate VGA input amplifier, an input band-pass filter, an I/Q demodulator with an input band-pass filter.
-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.
@@ Line 373: / Line 374: @@
 **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, I/Q demodulator with input band-pass filter.
+The design should include a separate input amplifier (VGA), an input band-pass filter to limit the possible intermodulation, an I/Q demodulator with an input band-pass filter.
-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.