Pulsed RF Calculator
Duty cycle = PW × PRF = PW ÷ PRI; average power = peak power × duty cycle; energy per pulse = peak × PW = average ÷ PRF. Example: 1 µs at 1 kHz is 0.1% duty (−30 dB), so 1 kW peak gives 1 W average and 1 mJ per pulse, with 149.9 km unambiguous range and 149.9 m range resolution.
Use the Pulsed RF Calculator
Input Parameters
Enter any two or more known values. Leave the rest blank.
Results
Enter parameters on the left and click Calculate to see results.
Pulsed RF formulas
Duty cycle & timing
DC = PW × PRF = PW / PRI
PRI = 1 / PRF. DC (dB) = 10·log10(DC).
Average power
Pavg = Ppeak × DC
In dB: Pavg (dBm) = Ppeak (dBm) + DC (dB).
Energy per pulse
E = Ppeak × PW = Pavg / PRF
1 W × 1 µs = 1 µJ (rectangular pulse).
Unambiguous range
Rmax = c × PRI / 2
c = 299,792.458 km/s. Timing limit, not detection range.
Range resolution
ΔR = c × PW / 2
Uncompressed pulse; also the minimum blind range.
Spectrum
Bnull = 2 / PW
sinc envelope, lines spaced at PRF; 3 dB width ≈ 0.886 / PW.
Duty cycle to dB
Add the dB value to a peak power in dBm to get average power, or subtract it from an average reading to get peak power.
| Duty cycle | dB | Peak / average | Example PW at 1 kHz |
|---|---|---|---|
| 50% | −3.01 | 2× | 500 µs |
| 25% | −6.02 | 4× | 250 µs |
| 10% | −10.00 | 10× | 100 µs |
| 5% | −13.01 | 20× | 50 µs |
| 1% | −20.00 | 100× | 10 µs |
| 0.5% | −23.01 | 200× | 5 µs |
| 0.1% | −30.00 | 1,000× | 1 µs |
| 0.01% | −40.00 | 10,000× | 100 ns |
| 0.001% | −50.00 | 100,000× | 10 ns |
Worked example
A transmitter sends 1 µs pulses at a PRF of 1 kHz with 1 kW peak power. PRI = 1/1000 Hz = 1 ms, so the duty cycle is 1 µs ÷ 1000 µs = 0.1%, or −30 dB.
Average power = 1000 W × 0.001 = 1 W (60 dBm − 30 dB = 30 dBm). Energy per pulse = 1000 W × 1 µs = 1 mJ, the same as 1 W ÷ 1000 Hz. The unambiguous range is 299,792.458 km/s × 1 ms ÷ 2 = 149.9 km (80.9 nmi). The range resolution is 299,792,458 m/s × 1 µs ÷ 2 = 149.9 m. The main lobe of the spectrum is 2 ÷ 1 µs = 2 MHz wide.
Summary
The Pulsed RF Calculator solves the full set of pulse-train relationships from whatever you know: pulse width (PW), pulse repetition frequency (PRF), pulse repetition interval (PRI), duty cycle, peak power, average power and energy per pulse. Each field has its own unit, including dBm and dBW for power and dB for duty cycle. It checks redundant inputs for consistency and adds the duty-cycle correction in dB, peak-to-average ratio, monostatic unambiguous range, range resolution and main-lobe bandwidth.
How it works
- Enter any two or more known values and pick each unit (ns, µs, ms, s; Hz, kHz, MHz; mW, W, kW, MW, dBm, dBW; nJ to J; duty cycle in % or dB).
- The solver applies PRI = 1/PRF, DC = PW/PRI, P_avg = P_peak × DC, E = P_peak × PW and E = P_avg × PRI repeatedly until nothing new can be found.
- If you enter more values than needed, they are cross-checked within 0.5% and a conflict names the relation that fails.
- Results show every quantity in engineering units, power in W and dBm, duty cycle in % and dB, plus pulse energy, peak-to-average ratio, unambiguous range, range resolution and bandwidth.
- Reset clears all fields and units.
Use cases
- Convert a spectrum analyzer or power meter average reading to peak power with the duty-cycle correction in dB.
- Find average power and heat load of a pulsed amplifier from its peak rating and duty cycle.
- Size pulse-forming networks and capacitor banks from the energy per pulse.
- Pick a PRF that gives the unambiguous range you need, and a pulse width for the range resolution.
- Check a test plan or datasheet for inconsistent PW, PRF and duty cycle values.
- Estimate the occupied bandwidth (2/PW null-to-null) of a rectangular pulse.