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pounder_test
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use round up half integer rounding

master
Matt Huszagh 2021-01-12 15:50:26 -08:00
parent 4c033c0f3e
commit 41ea2ebed4
2 changed files with 19 additions and 7 deletions
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6
dsp/src/lib.rs
View File

@ -20,6 +20,12 @@ pub fn shift_round(x: i32, shift: usize) -> i32 {
(x + (1 << (shift - 1))) >> shift
}
/// TODO consolidate with `shift_round`.
#[inline(always)]
pub fn shift_round64(x: i64, shift: usize) -> i64 {
(x + (1 << (shift - 1))) >> shift
}
/// Integer division, round up half.
///
/// # Arguments

20
src/main.rs
View File

@ -101,6 +101,7 @@ use dac::{Dac0Output, Dac1Output};
use dsp::{
divide_round, iir, iir_int,
pll::PLL,
shift_round, shift_round64,
trig::{atan2, cossin},
};
use pounder::DdsOutput;
@ -196,7 +197,7 @@ impl TimestampHandler {
}
}
/// Compute the initial phase value and frequency of the demodulation signal.
/// Compute the initial phase and frequency of the demodulation signal.
///
/// # Args
/// * `timestamp` - Counter value corresponding to an external reference edge.
@ -1087,10 +1088,15 @@ const APP: () = {
let mut signal = (0_i32, 0_i32);
signal.0 = ((adc_samples[0][i] as i16 as i64 * cos as i64)
>> 16) as i32;
signal.1 = ((adc_samples[0][i] as i16 as i64 * sin as i64)
>> 16) as i32;
// TODO should we shift cos/sin first to avoid i64?
signal.0 = shift_round64(
adc_samples[0][i] as i16 as i64 * cos as i64,
16,
) as i32;
signal.1 = shift_round64(
adc_samples[0][i] as i16 as i64 * sin as i64,
16,
) as i32;
signal.0 =
iir_lockin.update(&mut iir_state_lockin[0], signal.0);
@ -1100,8 +1106,8 @@ const APP: () = {
let magnitude = signal.0 * signal.0 + signal.1 * signal.1;
let phase = atan2(signal.1, signal.0);
*d0 = (magnitude >> 16) as i16 as u16;
*d1 = (phase >> 16) as i16 as u16;
*d0 = shift_round(magnitude, 16) as i16 as u16;
*d1 = shift_round(phase, 16) as i16 as u16;
},
);