Event:SoftwareDefinedRadioSDRFMDABontvangerworkshop - Revision history

Cmpxchg: /* Attendees */

2019-06-27T21:56:59Z

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Atoomnet: /* Attendees */

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Gábor Nyers: /* Attendees */

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Gábor Nyers: /* Attendees */

2019-06-05T22:09:17Z

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Pepman: /* Attendees */

2019-06-05T21:27:52Z

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Cmpxchg at 19:25, 5 June 2019

2019-06-05T19:25:41Z

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			== Software Defined Radio workshop: receiving a wireless microphone ==

	== 1. Goal of the workshop: ==		== 1. Goal of the workshop: ==

Cmpxchg at 19:24, 5 June 2019

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	Goal of the workshop:		== 1. Goal of the workshop: ==
	~~- To receive~~ a simple wireless microphone signal from the presenter~~, using your~~ own laptop
	+ software-defined radio receiver		At the end of the workshop (ca two hours), participants will be able to
	~~- To understand~~ a few basic concept of radio, signal processing, and software-based radio signalprocessing		* Receive a simple wireless microphone signal from the presenter
	in particular.		* Using their own laptop
			* Using their own RTL-SDR dongle or other software-defined radio receiver
			* Understand a few basic concept of radio signals, signal processing, and software-based radio signalprocessing in particular.

			== 2. Prerequisites: ==

	~~== 1 Prerequisites: ==~~
	Please bring your own radio-receiver:		Please bring your own radio-receiver:
	- A RTL-SDR hardware (very cheap, $20-$40 or less)		* A RTL-SDR hardware (very cheap, $20-$40 or less)
	- A funcube dongle		* A funcube dongle
	- Other SDR hardware (USRP or other GNURadio supported SDR)		* Other SDR hardware (USRP or other GNURadio supported SDR)
	- A laptop with GnuRadio and Gnuradio-companion installed (version 3.7.5 ... 3.7.11 is ok)		* A laptop with GnuRadio and Gnuradio-companion installed (version 3.7.5 ... 3.7.11 is ok)
	There might be a few available @ revspace coin-op machine by the time the workshop starts.		There might be a few available @ revspace coin-op machine by the time the workshop starts.
	- Optional: a gqrx installation or other software-defined radio/waterfall receiver with WBFM support		* Optional: a gqrx installation or other software-defined radio/waterfall receiver with WBFM support

	== 2. Quick introduction ==		== 3. Quick introduction ==
	Quick introduction into GNURadio companion 3.7.x user interface and concepts and keyboard shortcuts		Quick introduction into GNURadio companion 3.7.x user interface and concepts and keyboard shortcuts
	(have it preinstalled and git client to download the samplecode)		(have it preinstalled and git client to download the samplecode)

	== 3. Theory of signal processing ==		== 4. Theory of signal processing ==
	This takes about half an hour, it is an interactive session so		This takes about half an hour, it is an interactive session so
	that we can adapt the speed a bit depending on prior knowledge		that we can adapt the speed a bit depending on prior knowledge
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	we will be with a small group.		we will be with a small group.

	== 4. Practice of signal processing ==		== 5. Radio receivers and/or detectors ==
			* Build a simple mono FM receiver using standard gnuradio blocks
			* Decomposing the function of the gnuradio blocks

			The transmitter in question will be an ordinary wireless presentation microphone for stage-usage, that
			the presenter will bring and setup to transmit at a fixed frequency.

			It will generate a mono, wideband FM signal in the 473-494 MHz band.
			The transmitter will also feature a tone-code of 35 kHz that will be inaudible to the public and normal
			receivers. The tone is used to detect nearby presence of the transmitter, and estimate the
			signal level.

			The goal is to
			- find the exact frequency the presenter is using
			- demodulate the FM signal using basic gnuradio blocks
			- play back the audio from a local speaker or headphone

			The latter might also introduce one into the problem of samplerate-conversions and free-running clocks
			between the radio-receiver, audio device sample clock, and a PC's local software clock

			== 6. Practice of signal processing ==

	The examples will be provided via git and just need to be started,		The examples will be provided via git and just need to be started,
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	This takes about another half hour		This takes about another half hour

	== 4.1 Real signals ==		=== 6.1 Real signals ===
	Real sinewaves		Real sinewaves
	In the timedomain		* In the timedomain
	Displayed using time sink / oscillioscope		* Displayed using time sink / oscillioscope
	Displayed uisng frequency sink / FFT / spectrogram		* Displayed uisng frequency sink / FFT / spectrogram
	Multiplying real-sinewaves, in the time domain		Multiplying real-sinewaves, in the time domain
	Displayed using time sink / oscillioscope		* Displayed using time sink / oscillioscope
	Displayed uisng frequency sink / FFT / spectrogram		* Displayed uisng frequency sink / FFT / spectrogram
	Usage of the word 'mixing' in radioterms (multiplication or usage of other non-linearities)		* Usage of the word 'mixing' in radioterms (multiplication or usage of other non-linearities)

	== 4.2 Complex signals ==		=== 6.2 Complex signals ===
	Quadrature or complex (IQ) sinewave signal sources		Quadrature or complex (IQ) sinewave signal sources
	Displaying IQ signals in timedomain ('constellation' diagram)		* Displaying IQ signals in timedomain ('constellation' diagram)
	Displaying IQ signals in frequency domain (using FFT or frequency sinks)		* Displaying IQ signals in frequency domain (using FFT or frequency sinks)
	Multiplying quadrature (IQ) sinewaves and spectrogram		Multiplying quadrature (IQ) sinewaves and spectrogram
	Effect of quadrature multiplication (phases of are added)		* Effect of quadrature multiplication (phases of are added)
	Usage of complex multiplication in signal processing		* Usage of complex multiplication in signal processing

	== 4.3 Filtering complex signals ==		=== 6.3 Filtering complex signals ===
	Filtering IQ signals using FIR filters with complex taps. FIR or Finite Impulse Response filters. IIR filters will be skipped. Hilbert transform filters might be skipped too (generating complex analytical signals from real ones).		Filtering IQ signals using FIR filters with complex coefficient/taps.
			* FIR or Finite Impulse Response filters.
			* IIR filters will be skipped.
			* Hilbert transform filters might be skipped too (generating complex analytical signals from real ones).

	== 4.4 Calculating FIR filter coefficients or parameters ==		=== 6.4 Calculating FIR filter coefficients or parameters ===
	Filtering coefficients/taps, impulse response of filter		Filtering coefficients/taps, impulse response of filter
	Calculating FIR filter coefficients/taps using gr-filter		* Calculating FIR filter coefficients/taps using gr-filter
	Performance limitations, tradeoffs between		Performance limitations, tradeoffs between
	Computational complexity of filter (number of multiply/add operations per processed sample)		* Computational complexity of filter (number of multiply/add operations per processed sample)
	Steepness of cut-off frequency		* Steepness of cut-off frequency
	Flatness of passband of filter (integrity of signal that still should pass through the filter)		* Flatness of passband of filter (integrity of signal that still should pass through the filter)
	Depth and ripple of stopband of filter (flatness of suppression of unwanted signal)		* Depth and ripple of stopband of filter (flatness of suppression of unwanted signal)
	(Using inverse FFT/inverse DFT and windowing functions to determine filter coefficients/taps will be skipped)		* (Using inverse FFT/inverse DFT and windowing functions to determine filter coefficients/taps will be skipped)

	~~== 5. Radio receivers and/or detectors ==~~
	~~- Build a simple mono FM receiver using blocks using built-in feedback networks~~

	~~The transmitter in question is an ordinary wireless presentation microphone for stage-usage.~~
	~~It will generate a mono, wideband FM signal in the 473-494 MHz band.~~
	~~The transmitter will also feature a tone-code of 35 kHz that will be inaudible to the public and normal~~
	~~receivers. The tone is used to detect nearby presence of the transmitter, and estimate the~~
	~~signal level.~~

	~~The goal is to~~
	~~- find the frequency~~
	~~- demodulate the FM signal using basic gnuradio blocks~~

	=== Attendees ===		== Attendees ==

	{\|class="wikitable"		{\|class="wikitable"

Cmpxchg at 19:10, 5 June 2019

2019-06-05T19:10:26Z

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			Goal of the workshop:
			- To receive a simple wireless microphone signal from the presenter, using your own laptop
			+ software-defined radio receiver
			- To understand a few basic concept of radio, signal processing, and software-based radio signalprocessing
			in particular.

	== 1 Prerequisites: ==		== 1 Prerequisites: ==
	Please bring your own RTL-SDR hardware (very cheap, $20-$40 or less)		Please bring your own radio-receiver:
	~~or other~~ SDR hardware (USRP or other GNURadio supported SDR).		- A RTL-SDR hardware (very cheap, $20-$40 or less)
			- A funcube dongle
			- Other SDR hardware (USRP or other GNURadio supported SDR)
			- A laptop with GnuRadio and Gnuradio-companion installed (version 3.7.5 ... 3.7.11 is ok)
	There might be a few available @ revspace coin-op machine by the time the workshop starts.		There might be a few available @ revspace coin-op machine by the time the workshop starts.
			- Optional: a gqrx installation or other software-defined radio/waterfall receiver with WBFM support

	== 2. Quick introduction ==		== 2. Quick introduction ==
	Quick introduction into GNURadio companion 3.7.~~11.1~~ user interface and concepts and keyboard shortcuts		Quick introduction into GNURadio companion 3.7.x user interface and concepts and keyboard shortcuts
	(have it preinstalled and git client to download the samplecode)		(have it preinstalled and git client to download the samplecode)

	== 3. ~~Quick theory~~ of signal processing ==		== 3. Theory of signal processing ==
	This ~~could take~~ about ~~one to or 1~~.~~5 hours~~		This takes about half an hour, it is an interactive session so
	~~Interactive session~~		that we can adapt the speed a bit depending on prior knowledge
			of the participants. Questions in between are very welcome,
			we will be with a small group.

	== 3.1 Real signals ==		== 4. Practice of signal processing ==

			The examples will be provided via git and just need to be started,
			so the focus is understanding the signal flow, making modifications
			predict what will happen, and then test the result in practice.
			This takes about another half hour

			== 4.1 Real signals ==
	Real sinewaves		Real sinewaves
	In the timedomain		In the timedomain
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	Usage of the word 'mixing' in radioterms (multiplication or usage of other non-linearities)		Usage of the word 'mixing' in radioterms (multiplication or usage of other non-linearities)

			== 4.2 Complex signals ==
	== 3.2 Complex signals ==
	Quadrature or complex (IQ) sinewave signal sources		Quadrature or complex (IQ) sinewave signal sources
	Displaying IQ signals in timedomain ('constellation' diagram)		Displaying IQ signals in timedomain ('constellation' diagram)
Line 41:		Line 59:
	Usage of complex multiplication in signal processing		Usage of complex multiplication in signal processing

	== 3.3 Filtering complex signals ==		== 4.3 Filtering complex signals ==
	Filtering IQ signals using FIR filters with complex taps. FIR or Finite Impulse Response filters. IIR filters will be skipped.		Filtering IQ signals using FIR filters with complex taps. FIR or Finite Impulse Response filters. IIR filters will be skipped. Hilbert transform filters might be skipped too (generating complex analytical signals from real ones).

	== 3.4 Calculating FIR filter coefficients or parameters ==		== 4.4 Calculating FIR filter coefficients or parameters ==
	Filtering coefficients/taps, impulse response of filter		Filtering coefficients/taps, impulse response of filter
	~~(very quick) calculating~~ FIR filter coefficients/taps using gr-filter		Calculating FIR filter coefficients/taps using gr-filter
	Performance limitations, tradeoffs between		Performance limitations, tradeoffs between
	~~computational~~ complexity of filter (number of ~~multiplies~~ per processed sample)		Computational complexity of filter (number of multiply/add operations per processed sample)
	~~steepness~~ of cut-off frequency		Steepness of cut-off frequency
	~~flatness~~ of passband of filter (integrity of signal that still should pass through the filter)		Flatness of passband of filter (integrity of signal that still should pass through the filter)
	~~depth~~ and ripple of stopband of filter (flatness of suppression of unwanted signal)		Depth and ripple of stopband of filter (flatness of suppression of unwanted signal)
	Using inverse FFT/inverse DFT and windowing functions to determine filter coefficients/taps		(Using inverse FFT/inverse DFT and windowing functions to determine filter coefficients/taps will be skipped)

			== 5. Radio receivers and/or detectors ==
			- Build a simple mono FM receiver using blocks using built-in feedback networks

	~~== 4~~. ~~Radio receivers and/or detectors ==~~		The transmitter in question is an ordinary wireless presentation microphone for stage-usage.
	~~- Build~~ a ~~simple~~ mono FM ~~receiver using blocks with built~~-~~in feedback networks~~		It will generate a mono, wideband FM signal in the 473-494 MHz band.
	- ~~Build a RDS FM receiver~~ and ~~connect it with your RTL-SDR or other gnuradio-support SDR/radiodata input device~~		The transmitter will also feature a tone-code of 35 kHz that will be inaudible to the public and normal
			receivers. The tone is used to detect nearby presence of the transmitter, and estimate the
			signal level.

	~~== 5. Bonus ==~~		The goal is to
	~~Build with welle.io a SDR~~-~~based DAB+ receiver from source. For this a QTQuick 5.x installation might be required.~~		- find the frequency
			- demodulate the FM signal using basic gnuradio blocks

	=== Attendees ===		=== Attendees ===

Cmpxchg: /* 3. Quick 'theory' of signal processing */

2019-04-17T18:11:06Z

3. Quick 'theory' of signal processing

← Older revision		Revision as of 18:11, 17 April 2019
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	(have it preinstalled and git client to download the samplecode)		(have it preinstalled and git client to download the samplecode)

	== 3. Quick 'theory' of signal processing ==		== 3. Quick theory of signal processing ==
	This could take about ~~an hour~~ or 1.5 ~~hrs of interactive~~ session		This could take about one to or 1.5 hours
			Interactive session

	3.1 Real signals		== 3.1 Real signals ==
	~~- real-~~sinewaves in the timedomain ~~/ displayed~~ using time sink / oscillioscope		Real sinewaves
	- Multiplying real-sinewaves ~~and~~ frequency ~~domain~~/spectrogram (mixing in radioterms)		In the timedomain
			Displayed using time sink / oscillioscope
			Displayed uisng frequency sink / FFT / spectrogram
			Multiplying real-sinewaves, in the time domain
			Displayed using time sink / oscillioscope
			Displayed uisng frequency sink / FFT / spectrogram
			Usage of the word 'mixing' in radioterms (multiplication or usage of other non-linearities)

	~~3.2 Complex signals~~
	~~- Quadrature or complex (IQ) sinewave signal sources and displaying in timedomain ('constellation' diagram) and frequency domain (FFT)~~
	~~- Multiplying quadrature (IQ) sinewaves and spectrogram~~

	3.~~3 Filtering~~ complex signals		== 3.2 Complex signals ==
	~~- Filtering~~ IQ signals using ~~FIR filters with~~ complex ~~taps. FIR or Finite Impulse Response filters. IIR filters will be skipped.~~		Quadrature or complex (IQ) sinewave signal sources
			Displaying IQ signals in timedomain ('constellation' diagram)
			Displaying IQ signals in frequency domain (using FFT or frequency sinks)
			Multiplying quadrature (IQ) sinewaves and spectrogram
			Effect of quadrature multiplication (phases of are added)
			Usage of complex multiplication in signal processing

	3.4 Calculating FIR filter coefficients or parameters		== 3.3 Filtering complex signals ==
	- Filtering coefficients/taps, impulse response of filter		Filtering IQ signals using FIR filters with complex taps. FIR or Finite Impulse Response filters. IIR filters will be skipped.
	- (very quick) calculating FIR filter coefficients/taps using gr-filter
	- Performance limitations, tradeoffs between		== 3.4 Calculating FIR filter coefficients or parameters ==
	- computational complexity of filter (number of multiplies per processed sample)		Filtering coefficients/taps, impulse response of filter
	- steepness of cut-off frequency		(very quick) calculating FIR filter coefficients/taps using gr-filter
	- flatness of passband of filter (integrity of signal that still should pass through the filter)		Performance limitations, tradeoffs between
	- depth and ripple of stopband of filter (flatness of suppression of unwanted signal)		computational complexity of filter (number of multiplies per processed sample)
	- Using inverse FFT/inverse DFT and windowing functions to determine filter coefficients/taps		steepness of cut-off frequency
			flatness of passband of filter (integrity of signal that still should pass through the filter)
			depth and ripple of stopband of filter (flatness of suppression of unwanted signal)
			Using inverse FFT/inverse DFT and windowing functions to determine filter coefficients/taps

	== 4. Radio receivers and/or detectors ==		== 4. Radio receivers and/or detectors ==