This year’s college student electronic competition has ended, the following is an analysis of the E questions.

1. Task

Design and manufacture a wireless transceiver that performs mixed transmission of digital-analog signals on the same channel. Among them, the digital signal is composed of a set of 4 numbers from 0 to 9; the analog signal is a voice signal with a frequency range of 100 Hz to 5 kHz. Using wireless transmission, the carrier frequency range is 20~30MHz, the channel bandwidth is not more than 25kHz, and the shortest transmission distance between the transceiver equipment is not less than 100cm.

The transmitting end of the transceiver completes the combined processing of the digital signal and the analog signal, and modulates and transmits on the same channel.

The receiving end of the transceiver completes receiving and demodulating, and separates the digital signal and the analog signal. The digital signal is displayed with a digital tube, and the analog signal is observed with an oscilloscope.

2. Requirements

1. Basic requirements

(1) Realize analog signal transmission. The analog signal is a voice signal of 100 Hz to 5 kHz, and the demodulated analog signal waveform at the receiving end is required to have no obvious distortion. When only analog signals are being transmitted, the digital display on the receiving end is off.

(2) Realize digital signal transmission. First type in a group of 4 numbers from 0 to 9 and store and display them on the sending end, and then press the send button to continuously and cyclically transmit the digital signal. The digital signal is demodulated at the receiving end and displayed through 4 digital tubes. The response time required to start sending to the digital tube display is not more than 2 seconds. When the sender presses the stop button, the digital signal transmission is ended, and at the same time, the display of the transmitted numbers is cleared on the sender, and new numbers are waited for input.

(3) Realize the mixed transmission of digital-analog signals. Enter a group of numbers arbitrarily, mix and modulate with analog signals for transmission. The receiving end is required to be able to demodulate the digital signal and the analog signal correctly, the digital display is correct, and the analog signal waveform has no obvious distortion.

(4) The channel bandwidth of the transceiver is not more than 25kHz, and the carrier frequency range is 20~30MHz. It is required that the transceiver can be selected and set in no less than 3 carrier frequencies, and the specific carrier frequency is determined by itself.

2. Play part

(1) After the digital signal transmission is stopped at the transmitting end, the digital display at the receiving end will automatically go out after a 5 second delay.
(2) On the premise of meeting the basic requirements, the lower the power consumption of the transceiver, the better.
(3) On the premise of meeting the basic requirements, the frequency range of the analog signal transmitted by the transceiver is extended to 50Hz~10kHz.
(4) Others.

Three, description

(1) The digital and analog signals must be processed by the combined circuit first, and then modulated and transmitted on the same channel. The modulation method and modulation degree are determined by themselves. There should be an observation port at the output end of the combined circuit for the oscilloscope to observe the waveform changes of the combined signal.
(2) There must not be any connection between the transmitter and receiver of the transceiver.
(3) The transmitting end of the transceiver and the antenna are connected by SMA plugs, the transmitting end is F (female) head, and the antenna end is M (male) head. The length of the antenna does not exceed 1 meter.
(4) Both the transmitting end and the receiving end of the transceiver are powered by a single battery power supply, and the power supply circuit at the transmitting end should have a test port for supply voltage and current.
(5) The carrier frequency of the transceiver should be selected as far as possible to avoid environmental radio wave interference.
(6) The channel bandwidth in this topic is agreed to be the -40dB bandwidth of the modulated signal, which is measured by a spectrum analyzer. The details are shown in the figure below.

Topic analysis and project design

This topic is a relatively complete wireless transceiver system that requires simultaneous transmission of analog and digital signals.

According to the description of the analog signal transmission requirements in the title, the analog signal adopts the analog transmission method. The frequency range of the analog signal that needs to be transmitted is 50 Hz to 10 kHz. If AM modulation is used, the required channel bandwidth is 20 kHz.

The digital signal that needs to be transmitted is a 4-digit decimal number, plus redundant information such as the synchronization header and check code of the data frame, the number of bits that need to be transmitted should not exceed 40. The title also stipulates that the time from the beginning of the transmission to the terminal display should not exceed 2 seconds, so the actual transmission bit rate can be as low as 20bps. According to Shannon’s theorem, as long as the signal-to-noise ratio of the channel is not extremely bad, the channel bandwidth required for data transmission is extremely narrow, which is almost negligible compared with analog signals.

The channel bandwidth specified by the title is 25kHz, the analog signal occupies the middle 20kHz, and the bandwidth of 2.5kHz is left on both sides, and the above-mentioned digital channel is more than enough. Therefore, you can select a subcarrier frequency between 10kHz~12.5kHz (for example, 11.2kHz, which is the geometric average of 10kHz and 12.5kHz), and modulate this subcarrier with a digital signal to obtain a digital modulated signal (the simplest modulation method is OOK modulation).

Finally, the digital modulated signal and the analog signal are superimposed, and the superimposed mixed signal is modulated with AM modulation on the carrier, amplified and then sent to the antenna for transmission. The overall spectrum structure is as follows:

The circuit structure of this scheme is shown in the figure below.

In this scheme, the filter that distinguishes the two signals is the key.

The requirement of the low-pass filter of the analog signal is: there is a sufficiently large amount of attenuation near the sub-carrier frequency of the digital signal, and the attenuation at 12.5kHz should be greater than 40dB. According to these two requirements, it is a better choice to use a high-order elliptic filter and design the first zero frequency of the filter near the subcarrier frequency of the digital signal. For example, using a 7th-order elliptical low-pass filter with an in-band fluctuation of 0.5dB, the attenuation at 11.2kHz (digital subcarrier frequency) and greater than 12.5kHz can be greater than 45dB.

The requirement of the band pass filter of the digital signal is: There should be enough attenuation at 10kHz and 12.5kHz. Because the bandwidth of the digital signal is extremely low, cascading multiple point-pass filters is the simplest method. For example, if three point-pass filters with a center frequency of 11.2kHz and a Q value of 25 are cascaded, their total bandwidth is about 20Hz, and the attenuation at 10kHz and 12.5kHz is about 45dB.

The receiving part is a typical superheterodyne receiver structure, in which the analog signal reception is basically the same as that of an ordinary AM receiver.

The intermediate amplifier circuit should have an AGC function to ensure that the amplitude of the output signal does not change much when the receiving conditions change, so as to facilitate subsequent digital signal demodulation.

The decoder structure of the digital receiving part varies with the modulation method. If it is OOK modulation, the signal amplitude after the band-pass filter is the 1 and 0 of the baseband signal, and it can be sent to the microprocessor for decoding as long as it is reshaped by the comparator. If it is another modulation method, it may be necessary to restore the subcarrier as a synchronization signal before performing synchronization decoding.

Obviously, for the situation where the bandwidth of the two signals of this topic is wide and the other is narrow, as long as the spectrum is arranged reasonably, the above-mentioned hybrid transmission scheme is effective and the circuit is relatively simple. From the given parameters and basic requirements 1, description 1, and other conditions, it can be guessed that the proposition seems to be based on this mixed transmission scheme.

Congratulations to all those who made the short-list, in what were crowded fields, and particularly well done to the winning individuals, organisations and companies.

You can see the full list of awards below, with special thanks to all the sponsors, without whose loyal support the event could not take place!

The Winners

COMPANY

Best Campaign of the Year

Electrocomponents – Helping improve the lives of 100,000 people worldwide

Distributor of the Year, Sponsored by Panasonic

RS Components

Manufacturer of the Year, Sponsored by Publitek

KIOXIA Europe GmbH

Start-up Electronics Business of the Year

Crypto Quantique

PRODUCTS

Automotive Electronics Award, Sponsored by Rochester

Paragraf – GHS-A Hall Effect sensor for Mapping of EV Battery Cells

Award for Excellence in Product Design (High-reliability systems)

Microchip Technology – Microchip LX7720 Integrated Radiation-Hardened Motor Controller

Award for Excellence in Product Design (Medical), Sponsored by Analog Devices

OmniVision Technologies, Inc. – OH0TA OVMed Medical Image Sensor

Design Tools and Development Software Award, Sponsored by Swindon Silicon Systems

Percepio AB – Tracealyzer for Linux

Internet of Things Product of the Year, Sponsored by Micron

Crypto Quantique – Quantum-Drive Technology Creates the World’s Most Secure and Scalable IoT Security Platform

Passive and Electromechanical Product of the Year

Harwin plc – Kona Connector Series

Power System Product of the Year

Trameto Ltd. – Simple, Effective and Economical Power Management of Micro Energy Harvesting

Semiconductor Product of the Year (Analogue), Sponsored by Mouser Electronics

Crypto Quantique – On-Chip Analogue IP Enables Femtoamp-Level Measurement of Quantum

Semiconductor Product of the Year (Digital)

Ambarella, Inc. – CV5 Edge AI Vision SoC for Single 8K and 4K Multi-Imager AI Cameras

Test Product of the Year

Rohde & Schwarz – RTS: Accelerating the Development of Automotive Radar for Autonomous Driving

PEOPLE

Design Team of the Year, Sponsored by BWW

Ignys Ltd. – Electronics & Software Design Team Promote Innovation with a Heart

University Research (Readers’ Vote), Sponsored by RS Components

University of Bath – Tense your inner ear to control a computer

Educational Support Award

Electroncomponents – Grass Roots Education

Rising Star of the Year

Jessica Reading – Siemens plc

You can also view the original Elektra 2021 Shortlist on the dedicated Elektra Awards website.

Thank you, too, to the excellent host for the evening, BBC Breakfast presenter Charlie Stayt, and the improv comedy troupe The Noise Next Door.

Xilinx componentry includes  Zynq UltraScale+  EV Multi-Processor (MP) system-on-a-chip (SoC) and Zynq-7000 SoC devices.

The integrators are contributing FPGA IP, media framework software and production-ready products.

The products  are ready-to-ship, or ready to customise.

Multimedia streaming requires flexible AV interfaces, real-time video processing, support for different professional-grade video codecs, and a reliable high-bandwidth Ethernet transport layer for AV-over-IP, all of which are provided by Xilinx Zynq devices.

AV-over-IP is at the heart of broadcast endpoints and infrastructure, keyboard-video-mouse technologies, streaming endpoints, AV routers and switchers, video wall controllers and collaboration equipment.

Products include:

• Adeas and Nextera Video IP Cores – For vendors seeking to integrate a complete, but fully customizable ST 2110 AV-over-IP system into their own designs, Adeas and Nextera Video provide a fully-integrated hardware/software IP core set for ST 2110, ST 2059, ST 2022-6/8, IPMX, and NMOS (Networked Media Open Specification used for plug-and-play, system-level control of ST 2110 devices). All cores are modular for easy customization, enabling resource efficiency while being resolution- and network-speed independent, and supporting up to 8K+ and from 1G to 100G+. 

• Macnica Technology ME10 SoC – For equipment providers wanting to integrate a chip-level or system-on-module (SoM) solution for AV-over-IP, the ME10 SoC is the industry’s first single-chip, full-stack solution for the AIMS IPMX standard. Based on Xilinx technology, the ME10 SoC transports 4K HDMI video, audio and control data over 1GbE networks and offers the only interoperable, scalable and vendor-independent AV-over-IP solution. The ME10 SoC is at the heart of the related Macnica MPA1000 SoM, and the same development kit is used for both. This gives more flexibility and dramatically reduces the cost of adoption.

• Osprey Video Talon Encoders and Decoders  – Already used by broadcasters for live streaming of sports, Talon products offer real-time broadcast-quality encoding of 10-bit 4K UHD video between HDMI/SDI and reliable IP transport streaming. The low-power Zynq UltraScale+ EV MPSoC implementation for H.264/H.265 encoding and decoding enables the Talon products to be fanless. The complete Talon encoder and decoder products are available for OEM adoption with varying levels of customization possible.

• XVTEC XVC-ULTRA Encoder – Delivering real-time, broadcast-quality H.264/H.265 encoding of up to 4K UHD video streaming over IP, the XVC-ULTRA encoder leverages the ultra-low-latency mode of the Zynq UltraScale+ EV MPSoC codec, resulting in an end-to-end latency of less than 40ms. The XVC-ULTRA encoder can be deployed as OEM products with various customization options available. .

More information on the Xilinx Broadcast and Pro AV portfolio can be found at https://www.xilinx.com/broadcast.

Polarization refers to the phenomenon where things are polarized under certain conditions, causing their properties to deviate from their original state. Of course, electrode polarization occurs between the two electrodes (that is, the positive and negative electrodes, or the anode and cathode) of the electrolytic cell or battery. Let the positive charge accumulate around one electrode or restore the ability to continuously lose electrons; at the same time let the negative charge accumulate around the other electrode or restore the ability to continue accepting electrons.

1. The concept of electrode polarization

Under irreversible conditions, when a current flows through the electrode, an irreversible electrode reaction occurs. At this time, the electrode potential is different from the reversible electrode potential. The phenomenon that the electrode potential and the reversible electrode potential deviate when the electrode has a current is called electrode polarization. The characteristics of electrode polarization are: the cathode potential is more negative than the equilibrium potential (cathode polarization), and the anode potential is more positive than the equilibrium potential (anode polarization).

In the case of a reversible battery, the entire battery is in an electrochemical equilibrium state, and the two electrodes are also in equilibrium respectively. The electrode potential is determined by the Nernst equation, which is the balanced electrode potential. At this time, the current through the electrode is zero, that is, the rate of electrode reaction is zero. If a non-zero current is passed through the electrode, the electrode potential must deviate from the value of the equilibrium electrode potential. This phenomenon is called electrode polarization.

Electrode polarization (electrode polarization) When the Electronic conductor is in contact with the solution in the surrounding rock, it will form a galvanic double layer, resulting in a potential jump. This potential jump is called the electrode potential when the electronic conductor is in contact with the solution. When there is an external electric field, the relatively balanced electrode potential value will change. Usually the difference between the electrode potential under the action of constant current density and the relatively balanced electrode potential is called electrode polarization. Common ones are electrochemical polarization, concentration polarization and so on. The electromotive force caused by electrode polarization is called overvoltage.

2. Reasons for electrode polarization

The reason for electrode polarization: when there is an external electric field, the relatively balanced electrode potential value will change, leading to the appearance of electrode polarization.

1. When there is an external electric field, the relatively balanced electrode potential value will change. Generally, the deviation of the electrode potential under a certain current density from the relatively balanced electrode potential is called electrode polarization. Common ones are electrochemical polarization (activation polarization), concentration polarization and so on. The electromotive force caused by electrode polarization is called overpotential (overvoltage).

2. Electrode polarization can be divided into concentration polarization and chemical polarization
When the current passes through the battery or electrolytic cell, if the entire electrode process is controlled by the diffusion and convection of the electrolyte, the electrolyte concentration near the two poles is different from the body of the solution, causing the electrode potential of the anode and cathode to deviate from the equilibrium electrode potential. This phenomenon is called “concentration polarization”. It can be eliminated by vigorously stirring the solution. Chemical polarization is related to the activation energy of the reaction and cannot be eliminated.

3. The result of electrode polarization

An electrode, in the case of reversibility, has a certain degree of electrification on the electrode, and establishes the corresponding electrode potential jr. When a current flows through the electrode, if the electrode reaction at the electrode-solution interface does not proceed fast enough, resulting in a change in the degree of charge of the electrode, the electrode potential can also deviate from jr. Take the electrode (Pt)H2(g)|H as an example. When the reduction effect of the cathode occurs, since the rate of H changing to H2 is not fast enough, the electrons reaching the cathode cannot be consumed in time when the current passes, making the electrode more reversible. In this case, there is more negative electricity, so that the electrode potential becomes lower than jr. This lower potential can promote the activation of the reactant, that is, accelerate the conversion of H into H2. When (Pt)H2(g)|H is used as an anode to oxidize, because the rate of H2 changing to H is not fast enough, the lack of electrons on the electrode due to the current passing through is more serious than in the reversible situation, resulting in the electrode with More positive charge, so the electrode potential becomes higher than jr. This higher potential is conducive to promoting the activation of the reactants and accelerating the transformation of H2 into H. Extending this to all electrodes, a conclusion of universal significance can be obtained: when there is a current passing through, due to the slowness of the electrochemical reaction, the degree of charging of the electrode is different from that in the reversible situation, which leads to the phenomenon that the electrode potential deviates from jr, which is called “Activation polarization” or “electrochemical polarization”. When the electrode is activated and polarized, as in the concentration polarization, the cathode potential always becomes lower than jr, and the anode potential always becomes higher than jr. The absolute value of the difference between the electrode potential jI and jr caused by activation polarization is called “activation overpotential”. The magnitude of the activation overpotential is a measure of the activation polarization of the electrode.

The ecosystem that Silicon Catalyst has created lowers the capital expenses associated with the design and fabrication of silicon-based IC’s, Sensors, and MEMS devices by providing tools and services from a comprehensive network of In-Kind Partners (IKPs).

The Portfolio Companies in the incubator utilize IKP tools and services including design tools, simulation software, design services, foundry PDK access and MPW runs, test program development, tester access, and banking and legal services.

AlphaICs designs and develops the AI co-processors for delivering  AI compute on edge devices including inference with learning.

Lelantos  is developing IoT compatible gas sensors targeted at threat detection, industrial safety, environmental and air quality monitoring and medical diagnostics.

Oculi makes the SPU Sensing and Processing Unit which is a complete edge vision system on a chip with power, bandwidth and latency benefits.

Salience Labs is building a hybrid photonic-electronic chip for AI based on amassively parallel, ultra-high throughput Photonic Tensor Processing Unit which allows data to be modulated at up to 100 GHZ, and allows for high levels of parallelisation using multiplexing.

Sonical is building the world’s first ear computer running EarOS to give everyone  a personalised hearing experience and to control how they hear the world using AI and advanced audio processing.

Visual Dawn is developing a contact lens based AR hardware platform that relies upon the same hydrogel material used for corrective vision contact and is enabled by a biocompatible battery that eliminates the need for toxic electrolyte solution and electrode materials.