IntroductionThis stage adds the TX Mixer to the board and provides the modulation of the Dividers' output signals by the 4 I and Q signals from the OpAmps. The result is a double sideband RF waveform that will be coupled into the PA stage.
Bill of Materials
|C17||10uF/16 VDC Electrolytic||South-North|
|C18||150pF, ceramic, 5%||n/a|
|C53||0.1uF, smt 1206||smt|
|R17||3.32 K, 1/4W, 1%||East-West|
|R18||2.21 K, 1/4W, 1%||West-East|
|R19||49.9, 1/4W, 1%||North-South|
|R20||49.9, 1/4W, 1%||West-East|
|T01||T30-6 (yellow) (#30) (2.1 uH)||24T/2x11T|
|U03||FST3253 or SN74CBT3253D||SOIC 16|
- With limiting resistor:
- Without limiting resistor, you should get ~38.5 mA
- Enable the chip. Connect the R39 hairpin hole to ground. Take care to get the correct hole (the right-hand, hairpin hole)
- Inject 16kHz audio signal into line in Left (or right). (Can use Rocky or IQGen to provide signals out of the computer's sound card)
- Connect scope probe to the top right pad of L1
- The trace should show a clean double sideband signal.
- Try the same for the other line out feed.