Struct UvFast 

pub struct UvFast;

Fast — punctured to rate 2/3. 1600 net bps (+33 % vs AFSK 1200). Good-signal default. 63 % parity puncturing; kSR-greedy puncture selection delivers ~1 dB Eb/N0 gain over uniform-spread at the BP threshold.

Implementations

impl UvFast

pub const MODE: Mode = Mode::Fast

Puncturing posture for this sub-mode. Used by the bespoke TX / RX paths to pick the right puncture table.

Trait Implementations

impl Clone for UvFast

fn clone(&self) -> UvFast

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for UvFast

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for UvFast

fn default() -> UvFast

Returns the “default value” for a type.

impl FrameLayout for UvFast

const N_DATA: u32 = 120

240 codeword bits / 2 bits-per-symbol = 120 data symbols per LDPC block. (Unpunctured. Higher-rate modes transmit fewer ch bits per block but the trait-level constant describes the mother codeword.)

const N_SYNC: u32 = 4

One Costas-4 at the head of each LDPC block.

const T_SLOT_S: f32

uvpacket frames are not slot-aligned — value is informational only. Use the duration of one LDPC-block-sized “protocol unit” so callers that expect a non-zero T_SLOT_S see something reasonable.

const N_SYMBOLS: u32 = 124

Total channel symbols per frame (= N_DATA + N_SYNC). Excludes any GFSK ramp-up / ramp-down symbols that are a shaping artifact.

const N_RAMP: u32 = 0

Extra symbol slots on each side of the frame reserved for amplitude ramp (FT4 has 1 each side = 2; FT8 has 0 — ramp absorbed into the first/last data symbol envelope). Applied at the transmitter.

const SYNC_MODE: SyncMode

Sync-symbol layout. Most WSJT protocols use SyncMode::Block with dedicated Costas blocks (FT8/FT4/FST4); WSPR uses SyncMode::Interleaved with a per-symbol sync bit. Callers that only support block sync should read SYNC_MODE.blocks() and treat an empty slice as “unsupported”.

const TX_START_OFFSET_S: f32 = 0.0

Time (seconds) from the start of the slot-audio buffer to the start of the first frame symbol — the “dt = 0” reference point used by sync, signal subtraction, and DT reporting. FT8 = 0.5, FT4 = 0.5.

const CODEWORD_INTERLEAVE: Option<&'static [u16]> = None

Optional bit interleaver: permutation table such that cw[CODEWORD_INTERLEAVE[j]] is the codeword bit transmitted at channel-bit position j. Length must equal <Self as Protocol>::Fec::N when Some.

impl ModulationParams for UvFast

const NSPS: u32 = 10

1200 baud at 12 kHz sample rate → 10 samples / symbol.

const TONE_SPACING_HZ: f32 = 600.0

h = 0.5 → tone spacing = baud × h = 600 Hz.

const NDOWN: u32 = 4

12000 / 4 = 3000 Hz baseband window — clears the 800–2600 Hz tone span with margin.

const NTONES: u32 = 4

Number of FSK tones (M in M-ary FSK).

const BITS_PER_SYMBOL: u32 = 2

Information bits carried per modulated symbol (= log2(NTONES)).

const SYMBOL_DT: f32

Symbol duration in seconds (= NSPS / 12000).

const GRAY_MAP: &'static [u8]

Gray-code map: GRAY_MAP[tone_index] returns the NATURAL-bit pattern for that tone. The map covers at least the data alphabet (2^BITS_PER_SYMBOL entries) and at most the full tone set (NTONES entries). Protocols whose sync tones are part of the data alphabet (FT8 / FT4 / FST4 / WSPR) have len() == NTONES == 2^BITS_PER_SYMBOL; protocols that reserve additional sync-only tones (JT9, JT65, Q65) either trim the map to the data alphabet (JT9: 8 entries for 9 tones) or extend it with identity over the sync slots (JT65 / Q65). Pinned by tests/protocol_invariants.rs.

const GFSK_BT: f32 = 0.5

Gaussian bandwidth-time product. FT8 = 2.0, FT4 = 1.0, FST4 ≈ 1.0.

const GFSK_HMOD: f32 = 0.5

Modulation index h — the phase increment per symbol is 2π · h. FT8 and FT4 both use 1.0 (orthogonal tones at 1/T spacing).

const NFFT_PER_SYMBOL_FACTOR: u32 = 4

Per-symbol FFT size = NSPS * NFFT_PER_SYMBOL_FACTOR. FT8 = 2 (window is 2·NSPS), FT4 = 4 (window is 4·NSPS) — trade-off between frequency resolution and time localisation.

const NSTEP_PER_SYMBOL: u32 = 2

Coarse-sync time-step = NSPS / NSTEP_PER_SYMBOL. FT8 = 4 (quarter-symbol resolution), FT4 = 1 (symbol-granular).

const LLR_SCALE: f32 = 2.83

LLR scale factor applied after standard-deviation normalisation. FT8 uses 2.83 (empirical, from WSJT-X ft8b.f90). Different bits-per-symbol counts may shift the optimum — FT4’s 2-bit LLR dynamics are not identical to FT8’s 3-bit case.

impl Protocol for UvFast

const ID: ProtocolId = ProtocolId::UvPacket

Runtime tag used at FFI / WASM boundaries.

type Fec = Ldpc240_101

FEC codec carrying N_DATA * BITS_PER_SYMBOL coded bits.

type Msg = UvPacketRawMessage

Message codec consuming the FEC-decoded information bits.

impl Copy for UvFast