WIRE TRANSMISSION SYSTEM FOR TELEVISION 



627 



High- Frequency Network for Dry Weather. The complete network 

 for the correction at high frequencies under dry weather conditions 

 was designed in two parts, an attenuation equaUzer and a phaes 

 corrector. These two structures are illustrated in Fig. 6. The 



PHASE CORRECTOR 

 — TOTHP, 



L| = 8.533 MH. 02=01185 MR 



ATTENUATION EQUALIZER 



Hh 



Ri 



Rz: 



Ri 



Ri 



-&WVo- 



R| 



-<yVWo- 



Rl=68.65 OHM 

 03=08240 MR 



Hh 



C3 



R2=I242 OHM 

 L4=I4.83 MH. 



Fig. 7 — Weather change equalizing networks 



computed dry weather attenuation and phase delay resulting with 

 the use of the combined low-frequency and high-frequency networks 

 are illustrated in the curves of Figs. 3 and 4. It will be noted that the 

 corrected attenuation curve is constant to within approximately 

 ± 0.3 T U, while the corrected time of transmission falls well within 

 the prescribed limits. 



Weather Change Networks. Correction for the additional distortion 

 introduced by changes from dry to wet weather was provided by three 



