A Sustainable Radio Design?

Future radio receiver design ideas (from Ismo, Pete and other folks):

Antenna ➔ (BPF) ➔ BFR93A based pre-amp from mcHF project ➔ MC1496 (Mixer) ➔ 455 kHz IF ➔ Ceramic filter SMD (HCI) ➔ 'IF amplifier' (20-40 dB gain?) ➔ Overclocked Pico 2's ADC (3+ MSPS) ➔ Digital down-conversion and processing in digital domain ➔ Expose the processed audio samples over USB (Pico 2 acts as a sound card).

Benefits: This enables reception of SSB and CW signals! The 455 kHz IF with digital processing gives us the best of both analog selectivity (ceramic filter) and digital flexibility.

The Pico 2 (RP2350) with dual Cortex-M33 overclocked cores should handle:

• Digital mixing/down-conversion
• FIR/IIR filtering
• Demodulation
• USB audio streaming

Also, we are planning to build a opamp powered IF amplifier using the fast TI TLV3541 part. The LO comes from Si5351 as usual.

Note: Before trying the digital superhet version (above), I will likely be using MC1496 in a DCR design first.

We are hoping that MC1496 continues to be available!

References:

• https://www.n6qw.com/MC1496.html

• https://github.com/steve-m/hsdaoh-rp2350 (see internal_adc section)

  This way we can continue using RP2350 instead of moving to something like STM32H5 immediately

• BFO handling code: https://github.com/mpmarks/pico-adx/blob/master/src/main.cpp

• http://www.kh-gps.de/cd2003_rx.htm (old favorite)

• https://www.ti.com/product-category/amplifiers/op-amps/high-speed/overview.html (TLV3541)

• https://github.com/dawsonjon/PicoRX/tree/master/simulations (also for DSP code)

• https://sourceforge.net/projects/veroroute/