orion-sdr 0.0.61

Composable SDR/DSP block library targeting HF-to-EHF: analog and single-carrier digital modes, FT8/FT4, PSK31, OFDM/COFDM, and DVB-T/NB-DVB-T, with Python bindings.
Documentation 
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// Copyright (c) 2025-2026 G & R Associates LLC
// SPDX-License-Identifier: MIT OR Apache-2.0

use crate::core::{Block, WorkReport};
use crate::dsp::{Nco, mix_with_nco};
use num_complex::Complex32 as C32;

/// CW (keyed carrier) – envelope-shaped keyed NCO
#[derive(Debug, Clone)]
pub struct CwKeyedMod {
    nco: Nco,
    env: f32,
    alpha_rise: f32,
    alpha_fall: f32,
    gain: f32,
}

impl CwKeyedMod {
    /// `tone_hz`: CW tone frequency (baseband or RF, depending on usage)
    /// `rise_ms`/`fall_ms`: envelope time constants (to avoid key clicks)
    pub fn new(sample_rate: f32, tone_hz: f32, rise_ms: f32, fall_ms: f32) -> Self {
        let tau_r = (rise_ms.max(0.1) * 1e-3) * sample_rate;
        let tau_f = (fall_ms.max(0.1) * 1e-3) * sample_rate;
        let alpha_r = (-1.0 / tau_r).exp();
        let alpha_f = (-1.0 / tau_f).exp();
        Self {
            nco: Nco::new(tone_hz, sample_rate),
            env: 0.0,
            alpha_rise: alpha_r,
            alpha_fall: alpha_f,
            gain: 1.0,
        }
    }
    pub fn set_gain(&mut self, g: f32) {
        self.gain = g;
    }
}

impl Block for CwKeyedMod {
    type In = f32; // keying envelope 0..1 (you can derive this from audio or key events)
    type Out = C32; // IQ

    #[inline(always)]
    fn process(&mut self, input: &[f32], output: &mut [C32]) -> WorkReport {
        let n = input.len().min(output.len());
        let mut i = 0;
        let nn = n & !3;

        while i < nn {
            // 0
            let tgt0 = input[i].clamp(0.0, 1.0);
            self.env = if tgt0 >= self.env {
                self.alpha_rise * self.env + (1.0 - self.alpha_rise) * tgt0
            } else {
                self.alpha_fall * self.env + (1.0 - self.alpha_fall) * tgt0
            };
            output[i] = mix_with_nco(C32::new(self.env * self.gain, 0.0), &mut self.nco);

            // 1
            let tgt1 = input[i + 1].clamp(0.0, 1.0);
            self.env = if tgt1 >= self.env {
                self.alpha_rise * self.env + (1.0 - self.alpha_rise) * tgt1
            } else {
                self.alpha_fall * self.env + (1.0 - self.alpha_fall) * tgt1
            };
            output[i + 1] = mix_with_nco(C32::new(self.env * self.gain, 0.0), &mut self.nco);

            // 2
            let tgt2 = input[i + 2].clamp(0.0, 1.0);
            self.env = if tgt2 >= self.env {
                self.alpha_rise * self.env + (1.0 - self.alpha_rise) * tgt2
            } else {
                self.alpha_fall * self.env + (1.0 - self.alpha_fall) * tgt2
            };
            output[i + 2] = mix_with_nco(C32::new(self.env * self.gain, 0.0), &mut self.nco);

            // 3
            let tgt3 = input[i + 3].clamp(0.0, 1.0);
            self.env = if tgt3 >= self.env {
                self.alpha_rise * self.env + (1.0 - self.alpha_rise) * tgt3
            } else {
                self.alpha_fall * self.env + (1.0 - self.alpha_fall) * tgt3
            };
            output[i + 3] = mix_with_nco(C32::new(self.env * self.gain, 0.0), &mut self.nco);

            i += 4;
        }
        while i < n {
            let tgt = input[i].clamp(0.0, 1.0);
            self.env = if tgt >= self.env {
                self.alpha_rise * self.env + (1.0 - self.alpha_rise) * tgt
            } else {
                self.alpha_fall * self.env + (1.0 - self.alpha_fall) * tgt
            };
            output[i] = mix_with_nco(C32::new(self.env * self.gain, 0.0), &mut self.nco);
            i += 1;
        }
        WorkReport {
            in_read: n,
            out_written: n,
        }
    }
}