Adom Fields

@@ -1,25 +0,0 @@-# Adom Fields: noise and receivers (`--with noise`, `--with rf`)--Turn on `noise` when a switch node or a clock runs near quiet or sensitive nets, or power pours face the ground plane (cavities). Turn on `rf` on a receiver: an antenna, an oscillator, a mixer, an IF.--## Noise: plane resonance and crosstalk (0.7.8)--`analyze` also screens noise couplings, each finding with an action:-- **Cavities**: every power or switching pour facing the ground plane is a parallel-plate cavity; its lowest modes are solved on the real overlap (the Neumann Laplacian's eigenpairs by Lanczos with full reorthogonalisation, then Jacobi; f = c·k/(2π√εr); checked against the rectangle's c/(2a√εr) in the tests). A mode within 5 % of a strong tone (the switching harmonics up to ten times the edge's knee, `clocks` from the spec: a crystal or an LC oscillator no chip drives counts to its 5th harmonic, a logic clock further) is `cavity-resonance`, with an `add-part` capacitor at the mode's loudest point.-- **Crosstalk**: each quiet net (not a rail, not loaded, not tied to the aggressor through a capacitor, like a bootstrap) next to a switching node or a clock: closest approach, run within 1 mm, side and overlap capacitance, and the coupled step ΔV·Cm/(Cm+Cg). Over `crosstalkMv` (50) is `crosstalk`, with a `reroute` action (spacing, or a ground guard).-- `review.noise` holds the cavities' modes, the tones and the crosstalk table; `noise.json` holds the mode shapes for the app.--`ui view --quantity noise`: the largest cavity rings in 3D (its real modes, red and blue phases, white nodal lines), the switching copper pulses, and quiet nets glow by the millivolts they pick up, with arcs at the closest approach.--`ui view --quantity signals` (the Signals button pulls the layers apart): each `signals.capacitance` check lights its real overlap on both layers as two glowing plates with the electric field crossing between them as sparks, one check at a time (seven seconds each, or the one picked in the panel), tagged with its picofarads, overlap and dielectric; differential pairs glow red and blue, tagged with skew and impedance. The via barrels hide so the plates read.--## The copper stack, receivers and RF (0.7.16)--- Boards of two, four or six copper layers; plated pads only on real copper. `stackupMm` is one dielectric per real gap (else the board's stackup, else its thickness); `epsilonR` when the stackup has none. fields.json: `board.copperLayers`, `board.dielectricMm`, `board.stackupFrom`.-- `hot.<part>.tabNet` is optional: a leaded part's watts go through all its leads by pad area. With no `hot`, the temperature is only copper I²R and the output says it is not a thermal pass.-- `clocks`: `{net: Hz}` or `{net: {hz | minHz, maxHz, harmonics, amplitudeV}}` (a tuned LO). `bands`: `{name: {minHz, maxHz, ifHz, lowSideLo}}` for the frequency plan (`tone-in-band`, the band and its image). `sensitiveNets`: nets an oscillator must not reach (`circuit-path` issues with the parts on the way). `victimBudgetsMv`: a budget per victim net (µV for RF/IF inputs).-- Crosstalk is in the victim's impedance (its capacitors and resistors to ground or rails), sine for oscillators, step for switch nodes. Return path (`no-reference`) for every non-rail net on every layer: over ground, a supply plane or nothing. `antenna-ground-loop`, `stage-feed-unbypassed`, `solve-unconverged` are new kinds; `review.stageFeeds`, `review.noise.frequencyPlan`, `review.noise.circuitPaths`.--## Also in this area--- **Receiver screens** (0.8.8, `review.rf`): the LO level at the antenna (each circuit path from a `clocks` oscillator to a `sensitiveNets` net, solved as an AC network with transistors as their junction capacitances, cross-checked in ngspice, against FCC 15.111's -57 dBm: `lo-leak`), isolation between stages through a shared rail at the oscillator's frequency (`stage-isolation`, target 40 dB), the LO's own radiated emission against FCC class B at 3 m (`lo-emission`), and USB edge and FM IF-limiter odd harmonics in the frequency plan (`tone-in-band`). Tune with spec `rf`: `cbcPf`, `cbePf`, `antennaOhm`, `loLeakLimitDbm`, `stageIsolationDb`, `usbHighSpeed`, `limiter`. Screening estimates, not measurements.