.. _sphx_glr_auto_examples_receiver:

Receiver DSP
------------

Pulse shaping, channel estimation, synchronisation, blind modulation recognition.


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    <div class="sphx-glr-thumbcontainer" tooltip="A root-raised-cosine (RRC) transmit filter followed by the same matched filter at the receiver gives a raised-cosine overall response, whose zero crossings at every other symbol instant cancel the intersymbol interference (Nyquist&#x27;s criterion). The roll-off \beta trades bandwidth, (1 + \beta) R_s, against the length of the pulse tails and the sensitivity to timing errors — which the eye diagram shows.">

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  .. image:: /auto_examples/receiver/images/thumb/sphx_glr_plot_01_pulse_shaping_thumb.png
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  :doc:`/auto_examples/receiver/plot_01_pulse_shaping`

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      <div class="sphx-glr-thumbnail-title">Nyquist pulse shaping and the eye diagram</div>
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    <div class="sphx-glr-thumbcontainer" tooltip="A multipath channel is frequency selective, but OFDM with a cyclic prefix longer than its delay spread sees it as one flat fading coefficient per subcarrier, which a one-tap equaliser removes — provided the receiver knows it. The channel here is the Extended Vehicular A profile of 3GPP TS 36.101 (nine taps, 357 ns RMS delay spread) at a sampling rate of 3.84 MHz, with Clarke/Jakes Doppler (Zheng &amp; Xiao 2003).">

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  .. image:: /auto_examples/receiver/images/thumb/sphx_glr_plot_02_ofdm_channel_estimation_thumb.png
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  :doc:`/auto_examples/receiver/plot_02_ofdm_channel_estimation`

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      <div class="sphx-glr-thumbnail-title">OFDM over multipath: channel estimation</div>
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    <div class="sphx-glr-thumbcontainer" tooltip="Timing and frequency. The preamble of Schmidl &amp; Cox (IEEE Trans. Commun. 45(12), 1997) has two identical halves: their correlation peaks — on a plateau as long as the cyclic prefix — at the start of the symbol, and its phase gives the carrier frequency offset, here in units of the subcarrier spacing. The error variance of the offset falls as 1/\mathrm{SNR}.">

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  .. image:: /auto_examples/receiver/images/thumb/sphx_glr_plot_03_sync_mimo_ofdm_thumb.png
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  :doc:`/auto_examples/receiver/plot_03_sync_mimo_ofdm`

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      <div class="sphx-glr-thumbnail-title">OFDM synchronisation and MIMO-OFDM</div>
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    <div class="sphx-glr-thumbcontainer" tooltip="A receiver that does not know what it receives (spectrum monitoring, cognitive radio, an adaptive link before its first header) must find the modulation, the SNR and the symbol rate from the samples alone. comnum implements the classical methods:">

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  .. image:: /auto_examples/receiver/images/thumb/sphx_glr_plot_04_modulation_recognition_thumb.png
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  :doc:`/auto_examples/receiver/plot_04_modulation_recognition`

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      <div class="sphx-glr-thumbnail-title">Blind receiver: modulation recognition, SNR and symbol rate</div>
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.. toctree::
   :hidden:

   /auto_examples/receiver/plot_01_pulse_shaping
   /auto_examples/receiver/plot_02_ofdm_channel_estimation
   /auto_examples/receiver/plot_03_sync_mimo_ofdm
   /auto_examples/receiver/plot_04_modulation_recognition