On 16 Jun, 22:22, Postipoika
wrote:
Joel Koltner kirjoitti:

Just curious... does anyone know what sort of architecture you find in your
typical HT or mobile "receives everything from 100kHz - 1.3GHz!" radio to
generate such a vast range of frequencies while still keeping the prices so
low (plenty are available for $200, and I can't expect the LO makes up a
particularly large percentage of that total price)? *I would tend to lean
towards something PLL-based given the typically channelized nature of
available frequencies, but a single PLL would still need a VCO with a huge
tuning range. *So... perhaps a pair of mixed PLLs, with one doing the fine
tuning and another the coarse tuning (having been multiplied up from a low
frequency)?

I attempted to decipher the schematic included with my Yaesu FTM-10R, but
everything is so tiny it was rather hopeless!

I don't suppose any of the reviews ever go through and sweep the LOs while
watching for the worst case spur conditions, do they?

---Joel

Solution for LO maybe is DDS.
The practical solution of DDS is is extremely simple and cheap.
Please google word "DDS"

-- postipoika

My Yaesu FT-857D and FT-817ND transceivers use a PLL and DDS. The PLL
cleans up the DDS output and the DDS gives the fine tuning.

The 857 receives up to 450 MHz, and uses a 68.33 MHz first IF.

Leon