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wavemeter: simply output fringe positions for further processing

This commit is contained in:
Sebastien Bourdeauducq 2019-10-31 14:25:25 +08:00
parent c676c4facb
commit 110c55aefc
2 changed files with 8 additions and 105 deletions
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106
src/wavemeter.rs
View File

@ -35,13 +35,6 @@ struct Config {
refpll_kp: i64, // Proportionality constant of the DPLL loop filter.
ref_wavelength: f64, // Wavelength of the reference laser in m.
scan_displacement: f64, // Optical path difference across one scan cycle in m (use -c).
scan_decimation: u32, // Decimation factor for the scan positions.
scan_frequency: f64, // Frequency of the scan in Hz.
scan_speed_tol: f64, // Fraction of the nominal scan speed that is accepted as deviation
// from "smooth" motion.
scan_blanking: f64, // Fraction of the scan period that is blanked at the beginning
// and end of each slope (4 times per scan period).
}
fn read_config_from_file<P: AsRef<Path>>(path: P) -> Result<Config, Box<dyn Error>> {
@ -87,141 +80,56 @@ fn do_calibrate(config: &Config) {
})
}
enum MotionTrackerState {
BlankingIn(u32),
Smooth(u32),
BlankingOut
}
pub struct MotionTracker {
abs_speed_min: i64,
abs_speed_max: i64,
len_blanking_in: u32,
len_smooth: u32,
state: MotionTrackerState,
last_position: i64,
last_position_ago: u32,
speed: i64
}
impl MotionTracker {
pub fn new(abs_speed_min: i64, abs_speed_max: i64, len_blanking_in: u32, len_smooth: u32) -> MotionTracker {
pub fn new() -> MotionTracker {
MotionTracker {
abs_speed_min: abs_speed_min,
abs_speed_max: abs_speed_max,
len_blanking_in: len_blanking_in,
len_smooth: len_smooth,
state: MotionTrackerState::BlankingIn(0),
last_position: 0,
last_position_ago: 0,
speed: 0
}
}
fn speed_ok(&self) -> bool {
let abs_speed = self.speed.abs();
(self.abs_speed_min < abs_speed) && (abs_speed < self.abs_speed_max)
}
pub fn extrapolated_position(&self) -> i64 {
self.last_position + self.speed*(self.last_position_ago as i64)
}
pub fn tick(&mut self, position: Option<i64>, mut callback: impl FnMut(bool)) {
pub fn tick(&mut self, position: Option<i64>) {
self.last_position_ago += 1;
if let Some(position) = position {
self.speed = (position - self.last_position)/(self.last_position_ago as i64);
self.last_position = position;
self.last_position_ago = 0;
}
match self.state {
MotionTrackerState::BlankingIn(count) => {
let count = if self.speed_ok() { count + 1 } else { 0 };
if count == self.len_blanking_in {
self.state = MotionTrackerState::Smooth(0);
callback(true);
} else {
self.state = MotionTrackerState::BlankingIn(count);
}
},
MotionTrackerState::Smooth(count) => {
if self.speed_ok() {
let count = count + 1;
if count == self.len_smooth {
self.state = MotionTrackerState::BlankingOut;
callback(false);
} else {
self.state = MotionTrackerState::Smooth(count);
}
} else {
// abort
self.state = MotionTrackerState::BlankingIn(0);
}
},
MotionTrackerState::BlankingOut => {
if !self.speed_ok() {
self.state = MotionTrackerState::BlankingIn(0);
}
}
}
}
}
fn do_wavemeter(config: &Config) {
let mut first_fringe_position: i64 = 0;
let mut last_fringe_position: i64 = 0;
let mut fringe_count = 0;
let mut counting_fringes = false;
let mut refpll = noptica::Dpll::new(
noptica::Dpll::frequency_to_ftw(config.ref_min, config.sample_rate),
noptica::Dpll::frequency_to_ftw(config.ref_max, config.sample_rate),
config.refpll_ki,
config.refpll_kp);
let mut position_tracker = noptica::PositionTracker::new();
let mut position_decimator = noptica::Decimator::new(config.scan_decimation);
let abs_speed_nominal = 2.0*config.scan_displacement*config.scan_frequency;
let abs_speed_min = abs_speed_nominal*(1.0 - config.scan_speed_tol);
let abs_speed_max = abs_speed_nominal*(1.0 + config.scan_speed_tol);
let len_blanking_in = 2.0*config.scan_blanking/config.scan_frequency;
let len_smooth = (1.0 - 4.0*config.scan_blanking)/(2.0*config.scan_frequency);
let mut motion_tracker = MotionTracker::new(
(abs_speed_min/config.ref_wavelength*(noptica::Dpll::TURN as f64)/config.sample_rate) as i64,
(abs_speed_max/config.ref_wavelength*(noptica::Dpll::TURN as f64)/config.sample_rate) as i64,
(len_blanking_in*config.sample_rate) as u32,
(len_smooth*config.sample_rate) as u32);
let mut motion_tracker = MotionTracker::new();
noptica::sample(&config.sample_command, |rising, _falling| {
refpll.tick(rising & (1 << config.bit_ref) != 0);
let position = if rising & (1 << config.bit_meas) != 0 {
position_decimator.input(position_tracker.edge(refpll.get_phase_unwrapped()))
Some(position_tracker.edge(refpll.get_phase_unwrapped()))
} else {
None
};
motion_tracker.tick(position,
|enter| {
if enter {
counting_fringes = true;
fringe_count = 0;
} else {
counting_fringes = false;
if fringe_count > 1 {
let wavelength = (last_fringe_position - first_fringe_position).abs()/(fringe_count - 1);
let wavelength_m = (wavelength as f64)/(noptica::Dpll::TURN as f64)*config.ref_wavelength;
println!("{:.3} nm", 1.0e9*wavelength_m);
}
}
});
if counting_fringes && (rising & (1 << config.bit_input) != 0) {
motion_tracker.tick(position);
if rising & (1 << config.bit_input) != 0 {
let fringe_position = motion_tracker.extrapolated_position();
if fringe_count == 0 {
first_fringe_position = fringe_position;
}
last_fringe_position = fringe_position;
fringe_count += 1;
println!("{}", (fringe_position as f64)/(noptica::Dpll::TURN as f64));
}
})
}

7
wavemeter.json
View File

@ -10,10 +10,5 @@
"refpll_ki": 4294967,
"refpll_kp": 85899345,
"ref_wavelength": 632.991372e-9,
"scan_displacement": 40e-6,
"scan_decimation": 30,
"scan_frequency": 50.0,
"scan_speed_tol": 0.05,
"scan_blanking": 0.05
"ref_wavelength": 632.991372e-9
}