ransmission medium. Whereas with LOS microwave, the signal will pass through many repeaters, each degrading the signal somewhat. With the satellite there is one repeater, possibly two Table 16.3 Satellite Relay TV Performance Space Terrestrial End-to-End Parameters Segment Values Nominal impedance 75 So Return loss 30 dB Nonuseful dc component 0.5 V Nominal signal amplitude Insertion gain 0 0.25 dB 0 + 0.3 dB 0 0.5 dB Insertion gain variation (1 sec) £0.1 dB ₺0.2 dB £0.3 dB Insertion gain variation (1 hr) +0.25 dB +0.3 dB £0.5 dB Signal-to-continuous random noise 53 dBb 58 dB 51 dB Signal-to-periodic noise (0-1 kHz) 50 dB 45 dB 39 dB Signal-to-periodic noise (1 kHz-6 MHz) 55 dB 60 dB 53 dB Signal-to-impulse noise 25 dB 25 dB 25 DBc Crosstalk between channels (undistorted) 58 dB 64 dB 56 dB Crosstalk between channels (undifferentiated) 50 dB 56 dB 48 dB Luminance nonlinear distortion Chrominance nonlinear distortion (amplitude) Chrominance nonlinear distortion (phase) Differential gain (x or y) Differential phase (x or y) Chrominance-luminance intermodulation Gain-frequency characteristic (0.15-6 MHz) +0.5 dB +0.5 dBd +1.0 dBd Delay-frequency characteristic (0.15-6 MHz) +50 nsec +50 nsecd 105 nsecd aConnecting earth station to national technical control center. In cases where the receive earth station is colocated with the broadcaster's premises, a relaxation of up to 3 dB in video signal-to-weighted-noise ratio may be permissible. In this context, the term colocated is intended to represent the situation where the noise contribution of the local connection is negligible. Law of addition not specified in CCIR. Rec. 567. d Highest frequency: 5 MHz. Source: CCIR Rep. 965-1, Ref. 13. 6 Headend is where CATV programming derives its point of origin. See Section 17.2. 16.9 DIGITAL TELEVISION for world-wide coverage. However, care must be taken with the satellite delay problem if programming is interactive when two satellites in tandem relay a TV signal. Table 16.3 summarizes TV performance through satellite relay. 16.9 