rf_power: fix measurement
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 51.7 mV/dB at
- // 100MHz. It also indicates a y-intercept of -58dBm.
- Ok(analog_measurement / 0.0517 - 58.0)
+ // 100MHz with an intercept of -58 dBm.
+ // It is placed behind a 20 dB tap.
+ Ok(analog_measurement * (1. / 0.0517) + (-58. + 20.))
}
}
