Radio
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- BPF
- LPF+HPF=BPF
- What frequency range?
- How to implement? RL? RC? Do I need something more?
- Amplifier
- Do we need an amplifier? Is the incoming signal large enough?
- LPF:
- What frequency range?
- How to implement?
- Oscillator:
- Outputs a logic high and logic low. What is the best way to convert this to a co/sine wave (multiplex?)
- What value are we looking for?
- Frequency Range:
- FM is most likely too high to create
- AM radio (car stereo) is about right. Find a station you want to tune to. KFBK 1530?
- AM is allowed +- 5kHz
- 96kHz of bandwidth (due to what the audio card can sample)
- SI570 can create a number of frequencies
- Notes to organize:
- Switching Regulator
- SI570, KN9YIG
- Johnson counter
- Jumper selectable band pass filter?
- http://www.sdr-kits.net/USB/USB_Description.html
- Softrock is taking up about 40mA, USB provides 100mA for USB2, and up to 500mA for a high-powered USB 2.0 bus.
- Pick a logic family and stick with it: CMOS?
- Quad Analog switch for the multiplexer (Sine/Cosine). 74(V)HC4066 is one of them
- The 74VHC4066 doesn't go high enough. We need to use a Frequency Mixer instead, http://yu1lm.qrpradio.com/HF-VHF%20SDR%20receiver-part1-YU1LM.pdf
- Book questions
- Example 9.12, work through the math please
- Can oscillators produce sine waves without needing a square wave? Do we need to have potentiometers instead of resistors to make sine waves not clip?
- Class note questions
- What does LO stand for? Local Oscillator
- http://www.microwaves101.com/encyclopedia/mixerwaveforms.cfm