diff --git a/LICENSE b/LICENSE
index be1bebd..12849c6 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,3 +1,350 @@
+This software is licensed under the GNU GPL because it contains parts from https://github.com/kit-cel/lecture-examples.
+The rest of the software is also licensed under MIT License (see further down)
+
+GNU GENERAL PUBLIC LICENSE
+ Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
+ The licenses for most software are designed to take away your
+freedom to share and change it. By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users. This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it. (Some other Free Software Foundation software is covered by
+the GNU Lesser General Public License instead.) You can apply it to
+your programs, too.
+
+ When we speak of free software, we are referring to freedom, not
+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+ To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+ For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have. You must make sure that they, too, receive or can get the
+source code. And you must show them these terms so they know their
+rights.
+
+ We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+ Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software. If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+ Finally, any free program is threatened constantly by software
+patents. We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary. To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+ The precise terms and conditions for copying, distribution and
+modification follow.
+
+ GNU GENERAL PUBLIC LICENSE
+ TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+ 0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License. The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language. (Hereinafter, translation is included without limitation in
+the term "modification".) Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope. The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+ 1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+ 2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+ a) You must cause the modified files to carry prominent notices
+ stating that you changed the files and the date of any change.
+
+ b) You must cause any work that you distribute or publish, that in
+ whole or in part contains or is derived from the Program or any
+ part thereof, to be licensed as a whole at no charge to all third
+ parties under the terms of this License.
+
+ c) If the modified program normally reads commands interactively
+ when run, you must cause it, when started running for such
+ interactive use in the most ordinary way, to print or display an
+ announcement including an appropriate copyright notice and a
+ notice that there is no warranty (or else, saying that you provide
+ a warranty) and that users may redistribute the program under
+ these conditions, and telling the user how to view a copy of this
+ License. (Exception: if the Program itself is interactive but
+ does not normally print such an announcement, your work based on
+ the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole. If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works. But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+ 3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+ a) Accompany it with the complete corresponding machine-readable
+ source code, which must be distributed under the terms of Sections
+ 1 and 2 above on a medium customarily used for software interchange; or,
+
+ b) Accompany it with a written offer, valid for at least three
+ years, to give any third party, for a charge no more than your
+ cost of physically performing source distribution, a complete
+ machine-readable copy of the corresponding source code, to be
+ distributed under the terms of Sections 1 and 2 above on a medium
+ customarily used for software interchange; or,
+
+ c) Accompany it with the information you received as to the offer
+ to distribute corresponding source code. (This alternative is
+ allowed only for noncommercial distribution and only if you
+ received the program in object code or executable form with such
+ an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it. For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable. However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+ 4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License. Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+ 5. You are not required to accept this License, since you have not
+signed it. However, nothing else grants you permission to modify or
+distribute the Program or its derivative works. These actions are
+prohibited by law if you do not accept this License. Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+ 6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions. You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+ 7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License. If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all. For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices. Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+ 8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded. In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+ 9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time. Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number. If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation. If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+ 10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission. For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this. Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+ NO WARRANTY
+
+ 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+ 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+ {description}
+ Copyright (C) {year} {fullname}
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+ Gnomovision version 69, Copyright (C) year name of author
+ Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary. Here is a sample; alter the names:
+
+ Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+ `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+ {signature of Ty Coon}, 1 April 1989
+ Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs. If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.
+
+------------------
+
+For parts not marked as EXTERNAL:
+
The MIT License (MIT)
Copyright (c) 2013 Anton Schirg
diff --git a/analyse_audio.py b/analyse_audio.py
index 138dd70..41b2935 100644
--- a/analyse_audio.py
+++ b/analyse_audio.py
@@ -1,3 +1,5 @@
+# Contains code form https://github.com/kit-cel/lecture-examples/blob/master/nt1/vorlesung marked with EXTERNAL licensed under GPL
+
import numpy as np
import scipy_signal
@@ -101,6 +103,234 @@ def generate_signal(bits, chunk_length, sample_rate, frequency):
return data
+# EXTERNAL
+########################
+# find impulse response of an RC filter
+########################
+def get_rc_ir(K, n_up, t_symbol, r):
+
+ '''
+ Determines coefficients of an RC filter
+
+ Formula out of: K.-D. Kammeyer, Nachrichtenübertragung
+ At poles, l'Hospital was used
+
+ NOTE: Length of the IR has to be an odd number
+
+ IN: length of IR, upsampling factor, symbol time, roll-off factor
+ OUT: filter coefficients
+ '''
+
+ # check that IR length is odd
+ assert K % 2 == 1, 'Length of the impulse response should be an odd number'
+
+ # map zero beta to close-to-zero
+ if r == 0:
+ r = 1e-32
+
+
+ # initialize output length and sample time
+ rc = np.zeros( K )
+ t_sample = t_symbol / n_up
+
+
+ # time indices and sampled time
+ k_steps = np.arange( -(K-1) / 2.0, (K-1) / 2.0 + 1 )
+ t_steps = k_steps * t_sample
+
+ for k in k_steps.astype(int):
+
+ if t_steps[k] == 0:
+ rc[ k ] = 1.
+
+ elif np.abs( t_steps[k] ) == t_symbol / ( 2.0 * r ):
+ rc[k] = np.sin(np.pi/(2*r)) / (np.pi/(2*r)) * np.pi / 4
+ # rc[ k ] = r * np.sin( np.pi / r )
+ #
+ else:
+ rc[ k ] = np.sin( np.pi * t_steps[k]/t_symbol ) / (np.pi * t_steps[k]/t_symbol) \
+ * np.cos( r * np.pi * t_steps[k] / t_symbol ) \
+ / ( 1.0 - ( 2.0 * r * t_steps[k] / t_symbol )**2 )
+ # rc[ k ] = np.sin( np.pi * t_steps[k]/t_symbol ) / np.pi / t_steps[k] \
+ # * np.cos( r * np.pi * t_steps[k] / t_symbol ) \
+ # / ( 1.0 - ( 2.0 * r * t_steps[k] / t_symbol )**2 )
+
+ return rc
+
+
+########################
+# find impulse response of an RRC filter
+########################
+def get_rrc_ir(K, n_up, t_symb, r):
+
+ '''
+ Determines coefficients of an RRC filter
+
+ Formula out of: J. Huber, Trelliscodierung, Springer, 1992, S. 15
+ At poles, values of wikipedia.de were used (without cross-checking)
+
+ NOTE: Length of the IR has to be an odd number
+
+ IN: length of IR, upsampling factor, symbol time, roll-off factor
+ OUT: filter ceofficients
+ '''
+
+ assert K % 2 != 0, "Filter length needs to be odd"
+
+ if r == 0:
+ r = 1e-32
+
+ # init
+ rrc = np.zeros(K)
+ t_sample = t_symb/n_up
+
+
+ i_steps = np.arange( 0, K)
+ k_steps = np.arange( -(K-1)/2.0, (K-1)/2.0 + 1 )
+ t_steps = k_steps*t_sample
+
+ for i in i_steps:
+
+ if t_steps[i] == 0:
+ rrc[i] = 1.0/np.sqrt(t_symb) * (1.0 - r + 4.0 * r / np.pi )
+
+ elif np.abs( t_steps[i] ) == t_symb/4.0/r:
+ rrc[i] = r/np.sqrt(2.0*t_symb)*((1+2/np.pi)*np.sin(np.pi/4.0/r)+ \
+ ( 1.0 - 2.0/np.pi ) * np.cos(np.pi/4.0/r) )
+
+ else:
+ rrc[i] = 1.0/np.sqrt(t_symb)*( np.sin( np.pi*t_steps[i]/t_symb*(1-r) ) + \
+ 4.0*r*t_steps[i]/t_symb * np.cos( np.pi*t_steps[i]/t_symb*(1+r) ) ) \
+ / (np.pi*t_steps[i]/t_symb*(1.0-(4.0*r*t_steps[i]/t_symb)**2.0))
+
+ return rrc
+# END EXTERNAL
+
+import matplotlib
+matplotlib.use('TkAgg')
+import matplotlib.pyplot as plt
+
+# EXTERNAL
+def generate_constellation_points(M):
+ return [ np.exp( 1j * 2 * np.pi * m / M + 1j * np.pi / M ) for m in range( M ) ]
+# END EXTERNAL
+
+def generate_rc_filter(n_up, symbol_time):
+ syms_per_filt = 4
+ K_filt = 2 * syms_per_filt * n_up + 1
+ rc = get_rc_ir(K_filt, n_up, symbol_time, 0.33)
+ return rc / np.linalg.norm(rc)
+
+def generate_rrc_filter(n_up, symbol_time):
+ syms_per_filt = 4
+ K_filt = 2 * syms_per_filt * n_up + 1
+ rrc = get_rrc_ir(K_filt, n_up, symbol_time, 0.33)
+ #return rrc / np.linalg.norm(rrc)
+ return rrc / rrc[int(rrc.shape[0] / 2)]
+
+def generate_signal_new(symbols, n_up, sr, frequency):
+ M = 4
+ constellation_points = generate_constellation_points(M)
+
+ plt.plot(np.real(constellation_points), np.imag(constellation_points), 'o')
+ for i, xy in enumerate(zip(np.real(constellation_points), np.imag(constellation_points))):
+ plt.annotate(str(i), xy=xy, textcoords='data')
+ plt.show()
+
+ s = [ constellation_points[symbol] for symbol in symbols ]
+ n_symbols = len(s)
+ symbol_time = n_up / sr
+
+ rect = np.ones(n_up)
+
+ rrc = generate_rrc_filter(n_up, symbol_time) * 0.7
+
+ plt.plot(rrc)
+ print(rrc.shape)
+
+# EXTERNAL
+ s_up = np.zeros(n_symbols * n_up, dtype=np.complex128)
+ s_up[::n_up] = s
+ s_up = np.convolve(rrc, s_up)
+
+ plt.plot(np.abs(s_up))
+ plt.show()
+
+ plt.plot( np.real( s_up ), np.imag( s_up ), linewidth=2.0 )
+ plt.grid( True )
+ plt.xlabel( '$\mathrm{Re}\\{s(t)\\}$' )
+ plt.ylabel(' $\mathrm{Im}\\{s(t)\\}$' )
+ plt.title( 'QPSK signal' )
+ plt.show()
+# END EXTERNAL
+
+ t = np.linspace(0, s_up.shape[0]/sr, s_up.shape[0])
+ carrier = np.exp(-1j*2*np.pi*frequency*t)
+
+ modulated = np.real(s_up * carrier)
+ print(modulated.shape)
+
+ #plt.plot(modulated)
+ #plt.show()
+
+ return modulated
+
+def demodulate_signal(signal, n_data_symbols, n_up, sr, frequency):
+ M = 4
+ constellation_points = generate_constellation_points(M)
+ symbol_time = n_up / sr
+ n_symbols = n_data_symbols + 8 + 1 # 8 for rc, 1 for differential
+
+ signal = signal[:n_symbols * n_up]
+
+ t = np.linspace(0, n_symbols * symbol_time, n_symbols * n_up)
+ dem_carrier = np.exp(1j*2*np.pi*frequency*t)
+
+ demodulated = signal * dem_carrier
+
+ rrc = generate_rrc_filter(n_up, symbol_time)
+ rrc /= np.linalg.norm(rrc)
+ demodulated = np.convolve(demodulated, rrc[::-1])
+
+ sampled = demodulated[::n_up]
+ sampled = sampled[8:-8] #remove 2x rc length at sides
+
+ diff_dec = differential_decode_symbols(sampled)
+
+
+# EXTERNAL
+ plt.plot( np.real( demodulated ), np.imag( demodulated ), linewidth=2.0 )
+ plt.grid( True )
+ plt.xlabel( '$\mathrm{Re}\\{s(t)\\}$' )
+ plt.ylabel(' $\mathrm{Im}\\{s(t)\\}$' )
+ plt.title( 'Demodulated QPSK signal' )
+ plt.show()
+
+ plt.plot( np.real( diff_dec ), np.imag( diff_dec ), 'o', linewidth=2.0 )
+ for i, xy in enumerate(zip(np.real(diff_dec), np.imag(diff_dec))):
+ plt.annotate(str(i), xy=xy, textcoords='data')
+ plt.grid( True )
+ plt.xlabel( '$\mathrm{Re}\\{s(t)\\}$' )
+ plt.ylabel(' $\mathrm{Im}\\{s(t)\\}$' )
+ plt.title( 'Demodulated QPSK signal' )
+ plt.show()
+# END EXTERNAL
+
+ symbols = []
+ for s in diff_dec:
+ upper = np.imag(s) > 0
+ right = np.real(s) > 0
+ if upper and right:
+ symbols.append(0)
+ if upper and not right:
+ symbols.append(1)
+ if not upper and not right:
+ symbols.append(2)
+ if not upper and right:
+ symbols.append(3)
+
+ return symbols
+
def generate_chirp(f0, f1, duration, sample_rate):
ts = np.linspace(0, duration, duration * sample_rate)
@@ -117,6 +347,24 @@ def check_checksum(data):
return checksum == data[3]
+def differential_encode_symbol_nums(symbol_nums, M):
+ encoded = [0]
+ last = 0
+ for s in symbol_nums:
+ enc = (s + last) % M
+ last = enc
+ encoded.append(enc)
+ return encoded
+
+
+def differential_decode_symbols(symbols):
+ last = symbols[0]
+ decoded = np.zeros(symbols.shape[0] - 1, dtype=np.complex128)
+ for i, s in enumerate(symbols[1:]):
+ decoded[i] = s / last * (1+1j)
+ last = s
+ return decoded
+
def find_sync_signal(data, sr, sync_signal):
"""
@@ -129,4 +377,38 @@ def find_sync_signal(data, sr, sync_signal):
def bandpass(data, f, pass_width, sr):
filter_array = scipy_signal.firwin(128, [f-pass_width, f+pass_width], pass_zero=False, nyq=sr/2)
data2 = scipy_signal.fftconvolve(data, filter_array, mode='same')
- return data2
\ No newline at end of file
+ return data2
+
+if __name__ == "__main__":
+ import scipy_wavfile as wavfile
+ import random
+
+ random.seed(1337)
+ data = [random.randint(0, 3) for _ in range(64)]
+
+ print([9] + data)
+
+ diff_data = differential_encode_symbol_nums(data, 4)
+ print(diff_data)
+
+ sync_signal = generate_chirp(2000, 4000, 0.3, 48000)
+
+ data_signal = generate_signal_new(diff_data, 256, 48000, 4000)
+ signal = np.append(sync_signal, data_signal)
+ wavfile.write("test_new.wav", 48000, (signal * np.iinfo(np.int16).max).astype(np.int16))
+
+ sr, signal = wavfile.read("test_new_rec_rcc_bad.wav")
+ assert sr == 48000
+ signal = (signal[:,0]).astype(np.float) / np.iinfo(np.int16).max
+ print("read length ", signal.shape)
+
+ end_of_sync = find_sync_signal(signal, 48000, sync_signal)
+ print("end of sync: ", end_of_sync)
+ demod_data = demodulate_signal(signal[end_of_sync:], 64, 256, 48000, 4000)
+ ser = sum([int(orig != demod) for orig, demod in zip(data, demod_data)])/len(data)
+
+ print(data)
+ print(len(data))
+ print(demod_data)
+ print(len(demod_data))
+ print("SER: {}".format(ser))
diff --git a/default.nix b/default.nix
new file mode 100644
index 0000000..3cacf70
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,19 @@
+let
+ pkgs = import {};
+ stdenv = pkgs.stdenv;
+ pypkgs = pkgs.python36Packages;
+in rec {
+ audiosync = stdenv.mkDerivation rec {
+ name = "audiosync";
+ src = ./.;
+ nativeBuildInputs = [ pkgs.pkgconfig ];
+ buildInputs = [
+ pypkgs.numpy
+ pypkgs.tkinter
+ pkgs.ffmpeg
+
+#Debug
+ pypkgs.matplotlib
+ ];
+ };
+}