54 lines
2.0 KiB
TeX
54 lines
2.0 KiB
TeX
\chapter{Hardware Overview}
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\label{ch:hardware}
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This chapter describes the board at a block level. The complete hardware
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design --- schematics, PCB, Gerbers, and bill of materials --- is
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published in the repository under the CERN-OHL-S v2 licence.
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\section{System block diagram}
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DigiRadio is built around four devices coordinated by the ESP32-S3. The
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tuner produces the audio stream, the DSP conditions and mixes it, and the
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Bluetooth module transmits it; the host manages all three and provides
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the network interface.
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\begin{table}[htbp]
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\centering
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\begin{tabular}{@{}lll@{}}
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\drhead Device & Role & Interface \\
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\midrule
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Si4684 & DAB+/FM tuner & SPI / I\textsuperscript{2}C \\
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ADAU1701 & Audio DSP (EQ + mixer) & I\textsuperscript{2}C \\
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ESP32-S3-WROOM-1 & Host controller, Wi-Fi/BLE & --- \\
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FSC-BT1035 & Bluetooth 5.2 (aptX Adaptive) & UART (AT) \\
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\bottomrule
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\end{tabular}
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\caption{Principal integrated circuits and their roles.}
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\label{tab:hw-ics}
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\end{table}
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\section{Power}
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The board is powered from USB-C. An AP63203 buck converter generates the
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main rails from the USB input, feeding the digital and analogue sections.
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The tuner's sensitive supplies are derived and filtered separately to
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keep RF performance clean.
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\section{RF and antennas}
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Two 2.4\,GHz radios are present --- the ESP32-S3 and the Bluetooth module.
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Their antennas are placed on opposite diagonal corners of the board to
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maximise separation and minimise mutual desense. Each module keeps its
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antenna keep-out clear of copper on all layers.
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\begin{drnote}[Board]
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The PCB is a six-layer stack-up with controlled impedance on the USB and
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RF sections. The full fabrication data is in the repository.
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\end{drnote}
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\section{User interface and connectors}
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Configuration is done over Wi-Fi through a built-in web interface (see
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Chapter~\ref{ch:firmware}); no display is required on the board itself.
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Audio reaches the listener wirelessly over Bluetooth.
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