adom-fields 0.8.8

These are the receiver checks left open after the issue 9 review. Each is a screening estimate, in review.rf.

LO level at the antenna (lo-leak).
- The circuit: the circuit path from an oscillator to a sensitive net is solved as an AC network. It includes every part touching the path and each transistor's junction capacitances (Cbc, Cbe). The antenna is its port resistance.
- The result: dBm at the bottom, middle and top of a swept LO, cross-checked in ngspice, against FCC 15.111's 2 nW (-57 dBm).
- On the AM/FM receiver: about -41 dBm through C321, C313, Q301's Cbc and the HPF/BPF. ngspice agrees to 0.1 dB.
Isolation between stages through a shared rail (stage-isolation).
- The circuit: an oscillator stage's feed resistor, the rail with its capacitors and source, and each other stage's feed filter on that rail, at the oscillator's frequency, against 40 dB.
- On the AM/FM receiver: V_LO1 to V_RF1 on +5V_FM is 64.5 dB.
LO radiated emission (lo-emission).
- The estimate: the LO's copper is a small loop over its reference plane, carrying the current the LO voltage pushes into the copper and the parts, checked against FCC class B at 3 m.
- On the AM/FM receiver: 13.4 dBµV/m, 30 dB under.
USB and limiter harmonics in the frequency plan (tone-in-band).
- The tones: a full-speed USB pair's 12 MHz edge harmonics (480 MHz with rf.usbHighSpeed), and an FM IF limiter's odd harmonics of the IF.
- On the AM/FM receiver:
  - USB's 8th and 9th harmonics land in FM, and its 10th in the FM image.
  - The limiter's 9th harmonic of 10.7 MHz lands at 96.3 MHz, inside FM.
Spec rf: cbcPf, cbePf, antennaOhm, loLeakLimitDbm, stageIsolationDb, usbHighSpeed, limiter.

# adom-fields 0.8.8

These are the receiver checks left open after the issue 9 review. Each is a screening estimate, in `review.rf`.

- **LO level at the antenna (`lo-leak`).**
  - **The circuit:** the circuit path from an oscillator to a sensitive net is solved as an AC network. It includes every part touching the path and each transistor's junction capacitances (Cbc, Cbe). The antenna is its port resistance.
  - **The result:** dBm at the bottom, middle and top of a swept LO, cross-checked in ngspice, against FCC 15.111's 2 nW (-57 dBm).
  - **On the AM/FM receiver:** about -41 dBm through C321, C313, Q301's Cbc and the HPF/BPF. ngspice agrees to 0.1 dB.
- **Isolation between stages through a shared rail (`stage-isolation`).**
  - **The circuit:** an oscillator stage's feed resistor, the rail with its capacitors and source, and each other stage's feed filter on that rail, at the oscillator's frequency, against 40 dB.
  - **On the AM/FM receiver:** V_LO1 to V_RF1 on +5V_FM is 64.5 dB.
- **LO radiated emission (`lo-emission`).**
  - **The estimate:** the LO's copper is a small loop over its reference plane, carrying the current the LO voltage pushes into the copper and the parts, checked against FCC class B at 3 m.
  - **On the AM/FM receiver:** 13.4 dBµV/m, 30 dB under.
- **USB and limiter harmonics in the frequency plan (`tone-in-band`).**
  - **The tones:** a full-speed USB pair's 12 MHz edge harmonics (480 MHz with `rf.usbHighSpeed`), and an FM IF limiter's odd harmonics of the IF.
  - **On the AM/FM receiver:**
    - USB's 8th and 9th harmonics land in FM, and its 10th in the FM image.
    - The limiter's 9th harmonic of 10.7 MHz lands at 96.3 MHz, inside FM.
- **Spec `rf`:** `cbcPf`, `cbePf`, `antennaOhm`, `loLeakLimitDbm`, `stageIsolationDb`, `usbHighSpeed`, `limiter`.

Adom Fields

adom-fields 0.8.8