rf_power: fix measurement

This commit is contained in:
Robert Jördens 2021-05-26 14:09:26 +00:00
parent fc78b087ee
commit 79f8838104
1 changed files with 9 additions and 7 deletions

View File

@ -1,20 +1,22 @@
use super::{Channel, Error};
/// Provide an interface to measure RF input power in dB.
/// Provide an interface to measure RF input power in dBm.
pub trait PowerMeasurementInterface {
fn sample_converter(&mut self, channel: Channel) -> Result<f32, Error>;
/// Measure the power of an input channel in dBm.
///
/// Note: This function assumes the input channel is connected to an AD8363 output.
///
/// Args:
/// * `channel` - The pounder channel to measure the power of in dBm.
/// * `channel` - The pounder input channel to measure the power of.
///
/// Returns:
/// Power in dBm after the digitally controlled attenuator before the amplifier.
fn measure_power(&mut self, channel: Channel) -> Result<f32, Error> {
let analog_measurement = self.sample_converter(channel)?;
// The AD8363 with VSET connected to VOUT provides an output voltage of 51.7mV / dB at
// 100MHz. It also indicates a y-intercept of -58dBm.
Ok(analog_measurement / 0.0517 - 58.0)
// The AD8363 with VSET connected to VOUT provides an output voltage of 51.7 mV/dB at
// 100MHz with an intercept of -58 dBm.
// It is placed behind a 20 dB tap.
Ok(analog_measurement * (1. / 0.0517) + (-58. + 20.))
}
}