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Add some functions to convert between various units

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This commit is contained in:
adrian 2011-12-02 19:13:53 +02:00
parent 6179c26a04
commit 3340694170
2 changed files with 25 additions and 3 deletions
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20
src/Radio/radio.cxx
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@ -871,10 +871,13 @@ double FGRadioTransmission::LOS_calculate_attenuation(SGGeod pos, double freq, i
if (distance_m > total_horizon) {
return -1;
}
double pol_loss = 0.0;
if (_polarization == 1) {
pol_loss = polarization_loss();
}
// free-space loss (distance calculation should be changed)
dbloss = 20 * log10(distance_m) +20 * log10(frq_mhz) -27.55;
signal = link_budget - dbloss;
signal = link_budget - dbloss + pol_loss;
SG_LOG(SG_GENERAL, SG_BULK,
"LOS:: Link budget: " << link_budget << ", Attenuation: " << dbloss << " dBm ");
//cerr << "LOS:: Link budget: " << link_budget << ", Attenuation: " << dbloss << " dBm " << endl;
@ -912,3 +915,16 @@ double FGRadioTransmission::polarization_loss() {
}
double FGRadioTransmission::power_to_dbm(double power_watt) {
return 10 * log10(1000 * power_watt); // returns dbm
}
double FGRadioTransmission::dbm_to_power(double dbm) {
return exp( (dbm-30) * log(10) / 10); // returns Watts
}
double FGRadioTransmission::dbm_to_microvolt(double dbm) {
return sqrt(dbm_to_power(dbm) * 50) * 1000000; // returns microvolts
}

8
src/Radio/radio.hxx
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@ -66,7 +66,7 @@ public:
FGRadioTransmission();
~FGRadioTransmission();
// a couple of setters and getters for convenience
void setFrequency(double freq, int radio);
double getFrequency(int radio);
void setTxPower(double txpower) { _transmitter_power = txpower; };
@ -79,6 +79,12 @@ public:
void setRxLineLosses(double rx_line_losses) { _rx_line_losses = rx_line_losses; };
void setPropagationModel(int model) { _propagation_model = model; };
void setPolarization(int polarization) { _polarization = polarization; };
// accessory functions for unit conversions
double power_to_dbm(double power_watt);
double dbm_to_power(double dbm);
double dbm_to_microvolt(double dbm);
// transmission_type: 0 for air to ground 1 for ground to air, 2 for air to air, 3 for pilot to ground, 4 for pilot to air
void receiveATC(SGGeod tx_pos, double freq, string text, int transmission_type);
void receiveChat(SGGeod tx_pos, double freq, string text, int transmission_type);