2.3.3 Spurious responses Spurious responses to unwanted signals can be expected to occur in receivers at frequencies related to the receiver local oscillator frequency (lo)and the receiver intermediate frequencies (IF). The frequencies at which spurious responses can occur should be calculated using the following expressions.   q fsp nflo fIF where: harmonic order of the mixer input signal q: : frequency at which a spurious response may occur fsp harmonic order of the local oscillator n: : frequency of the local oscillator applied to the mixer stage flo The above equation provides the receiver spurious response frequency which produces a signal at the centre of the receiver IF band. Therefore, receiver spurious responses may occur over a frequency range of plus or minus one-half the receiver IF bandwidth. The protection which applies when the vision or sound carrier of a TV signal occurs at these spurious response frequencies is typically 70 dB. Under these circumstances, the power of the relevant carrier (vision or sound) should be used when calculating the level of the unwanted signal. 3. Protection margin 3.1 Assessment of the protection margin The protection margin (PM) is given by: (dB) = PM FS – NF – AF where: minimum field-strength value (dB(V/m)) given in § 1 FS: nuisance field and is determined by: NF: = + NF FI PR interfering field strength of the broadcasting signal. The appropriate propagation curves for 10% of time and FI: 50% of locations of Recommendation ITU-R P.1546 should be used protection (dB) given in § 2 of this Annex PR: adjustment factor (dB) to deal with receiver antenna gain discrimination and polarization discrimination (see § 4). AF: The calculated protection margin should be positive at all locations the fixed service is required. 4. Additional factors to consider 4.1 Receiving antenna discrimination The receiving antenna discrimination is determined by taking into account the receiver antenna gain in the direction of the TV broadcasting station. See Recommendation ITU-R F.699 for determination of the receiving antenna discrimination. 4.2 Receiving antenna cross-polarization discrimination For fixed stations, the value of the antenna discrimination against orthogonal polarization could be up to 15 dB in the mainbeam. Where non-orthogonal or mixed polarization are used, no antenna polarization discrimination should be taken into account.
2.3.3 Spurious responses Spurious responses to unwanted signals can be expected to occur in receivers at frequencies related to the receiver local oscillator frequency (lo)and the receiver intermediate frequencies (IF). The frequencies at which spurious responses can occur should be calculated using the following expressions. q fsp  nflo  fIF where: q: harmonic order of the mixer input signal fsp : frequency at which a spurious response may occur n: harmonic order of the local oscillator flo : frequency of the local oscillator applied to the mixer stage The above equation provides the receiver spurious response frequency which produces a signal at the centre of the receiver IF band. Therefore, receiver spurious responses may occur over a frequency range of plus or minus one-half the receiver IF bandwidth. The protection which applies when the vision or sound carrier of a TV signal occurs at these spurious response frequencies is typically 70 dB. Under these circumstances, the power of the relevant carrier (vision or sound) should be used when calculating the level of the unwanted signal. 3. Protection margin 3.1 Assessment of the protection margin The protection margin (PM) is given by: PM (dB) = FS – NF – AF where: FS: minimum field-strength value (dB(V/m)) given in § 1 NF: nuisance field and is determined by: NF = FI + PR FI: interfering field strength of the broadcasting signal. The appropriate propagation curves for 10% of time and 50% of locations of Recommendation ITU-R P.1546 should be used PR: protection (dB) given in § 2 of this Annex AF: adjustment factor (dB) to deal with receiver antenna gain discrimination and polarization discrimination (see § 4). The calculated protection margin should be positive at all locations the fixed service is required. 4. Additional factors to consider 4.1 Receiving antenna discrimination The receiving antenna discrimination is determined by taking into account the receiver antenna gain in the direction of the TV broadcasting station. See Recommendation ITU-R F.699 for determination of the receiving antenna discrimination. 4.2 Receiving antenna cross-polarization discrimination For fixed stations, the value of the antenna discrimination against orthogonal polarization could be up to 15 dB in the mainbeam. Where non-orthogonal or mixed polarization are used, no antenna polarization discrimination should be taken into account.
R-REC-SM.851-1-199304-I!!MSW-E.docx