2.2.2 Necessary Bandwidth 2.2.2.1 Recommendation ITU-R SM.853-1 provides the following additional formulae for determining the necessary bandwidth which for primary radar is assumed to be the 20 dB Bandwidth: Rectangular/Trapezoidal pulses (2) Smaller of: Frequency modulated pulses (3) Frequency Hopping (4) Carrier Wave (5) Where = necessary bandwidth Bn = frequency deviation Bc = maximum frequency range over which the carrier will be shifted Bs = maximum frequency deviation Bd = pulse duration at half amplitude t = pulse duration at half amplitude tr 2.2.2.2 The above formulae are also contained in Recommendation ITU-R SM.1541-6 in annex 8 that addresses primary radar, where it is confirmed that they relate to the 20 dB bandwidth. 2.2.3 Formulas for the dB bandwidth B−40 2.2.3.1 Recommendation ITU-R SM.1541-6 also provide formulae for determining the 40 dB Bandwidth (B−40) for primary radar, on the basis that the ratio of the B-40 and necessary bandwidth is not in general a constant Non-FM pulse Smaller of: (6) where the coefficient is 6.2 for radars with output power greater than 100 kW K and 7.6 for lowerpower radars and radars operating in the radionavigation service in the 2 900-3 100 MHz and 9 200-9 500 MHz bands. The latter expression applies if the rise time is less than about 0.0094t when is 6.2, or about 0.014t when tr K K is 7.6 FM pulsed where: (7) to account for the rise time
2.2.2 Necessary Bandwidth 2.2.2.1 Recommendation ITU-R SM.853-1 provides the following additional formulae for determining the necessary bandwidth which for primary radar is assumed to be the 20 dB Bandwidth: Rectangular/Trapezoidal pulses Smaller of: (2) Frequency modulated pulses (3) Frequency Hopping (4) Carrier Wave (5) Where Bn = necessary bandwidth Bc = frequency deviation Bs = maximum frequency range over which the carrier will be shifted Bd = maximum frequency deviation t = pulse duration at half amplitude tr = pulse duration at half amplitude 2.2.2.2 The above formulae are also contained in Recommendation ITU-R SM.1541-6 in annex 8 that addresses primary radar, where it is confirmed that they relate to the 20 dB bandwidth. 2.2.3 Formulas for the B−40 dB bandwidth 2.2.3.1 Recommendation ITU-R SM.1541-6 also provide formulae for determining the 40 dB Bandwidth (B−40) for primary radar, on the basis that the ratio of the B-40 and necessary bandwidth is not in general a constant Non-FM pulse Smaller of: where the coefficient K is 6.2 for radars with output power greater than 100 kW and 7.6 for lowerpower radars and radars operating in the radionavigation service in the 2 900-3 100 MHz and 9 200-9 500 MHz bands. The latter expression applies if the rise time tr is less than about 0.0094t when K is 6.2, or about 0.014t when K is 7.6 (6) FM pulsed where: to account for the rise time (7)
FSMP-WG03-WP09_Radar%20Spectral%20Mask.docx