Technical talks for 2008 - PowerPoint PPT Presentation

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Technical talks for 2008

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  1. Technical talks for 2008

  2. The design of HFTransmitters,Receivers,and Antennas.

  3. The format of the talksThe talks will be semi theoreticalSpeakers should be available for discussions afterwards or on other weeksSome will want a deeper understandingOthers just want to use technology confidently

  4. Practical examples will be used where possibleSuitable group projects will be identifiedAnonymous feedback forms will be used

  5. Reference designsIn order to retain our focus we will regularly refer to the circuit diagrams of two kits.The BITX20 and the SoftRock 40/80m.


  6. BITX20 Picture from Hendricks QRP Kits

  7. It’s a fairly simple transceiverIt uses few circuit variationsIt does not use software Why the BITX20?

  8. We will learn to break down “big” circuit diagrams (next)Don’t Panic!

  9. BITX20 bidirectional SSB transceiver

  10. A BITX20 single stage

  11. We will learn to break down small circuit diagrams even smaller.(Another day)

  12. SoftRock RxTx 40/80m Picture from Nicolas M1HOG.com

  13. It uses a range of circuit variationsIt is a more modern designIt introduces digital techniques Why the SoftRock RxTx?

  14. SoftRock Receiver

  15. Many of the same principles are used in the: The SDR Transmitter(avert your eyes for now if you like)

  16. SoftRock Transmitter

  17. These circuits were just to set the scene.We will come back to them during the following talks:-

  18. FundamentalsCurrent, voltageConductors, resistorsPotential dividersKirchoff's laws

  19. Signals & test equipmentDC / ACSignal GeneratorsGraphs, Time, Amplitude, Frequency, Phase(using visualisation tools)Oscilloscopes (practical to follow)RC Bridges & Grid Dip Oscillators

  20. Electric and Magnetic FieldsElectric fields, capacitorsMagnetic Fields (Using visualisation tools)Magnetic Materials, Inductors and Transformers (Bifilar winding, Baluns)

  21. Analogue circuit designDiodes, Transistors (Bipolar, FET), ValvesTransistor circuits: Common emitter, emitter follower, common base, biasing, feedback.Transistor pairs: Cascode, long tailed, mirror.

  22. Introduction to integrated circuitsICs are not scary: lets look insideOperational amplifiers & their internal designGates, flip-flops, transmission gates

  23. The first commercial op-amp, the K2-W 1952 http://www.ieee.org/portal/site/sscs/menuitem.f07ee9e3b2a01d06bb9305765bac26c8/index.jsp?&pName=sscs_level1_article&TheCat=2171&path=sscs/07Fall&file=Lee.xml

  24. Analogue signal processingSuperhet (supersonic heterodyne) receiversMixers (multipliers). Single / double balancedFilters (RC, RC active, LCR passive)Filter design with passives or op-amps

  25. Electro Magnetic Fields (e.g. radio waves)Transmission lines / coax cablesPropagating EM FieldsFundamental Antenna theory (dipoles)Antenna matching / tuningPhased arrays / Yagis

  26. Digital signal processingDigital Communications e.g. PSK31A/D & D/A, Shannon’s law, sampling theory Some more logic circuitsDirect Digital Synthesis (DDS)Digital filters and their design

  27. Demonstrations of digital signal processingThese will be non-theoretical demonstrations of signal processing using a Field Programmable Gate Array (FPGA) demo system.If interested this can be followed up with more detail and a live demonstration of programming