Reception of ground wave digital broadcasting using CATV
The reception of the ground wave digital broadcasting using CATV is a method to receive the ground wave digital broadcasting by using the signal of the cable that not the method received with usual UHF aerial but the CATV trader set up.
Method of receiving ground wave digital broadcasting by using CATV
If CATV is used, UHF aerial becomes unnecessary at each home. Because the signal of CATV is transmission with the cable, a steady broadcast wave can be received. The ground wave digital broadcasting can be received with CATV by the following methods. If these methods are not understood, it is not possible to receive it well.
When the BS digital broadcasting is received, the BS antenna is separately necessary though it is natural.
- The same frequency pass-through method
- Frequency conversion pass-through method
- Transformer modulation method
The same frequency pass-through method
Because this is transmitted like the frequency broadcast by UHF, it is called the same frequency pass-through method. This method is an antenna of UHF and a method with problems least. reception and any kooky [wari]It is adopted in a lot of CATV companies.
Frequency conversion pass-through method
The frequency conversion pass-through method is a method that converts the frequency of the ground wave digital broadcasting broadcast by UHF into a low frequency for CATV once and transmits. Therefore, the tuner, the television, and the DVD recorder, etc. for the ground digital television that corresponds to the frequency conversion pass-through method are necessary.
When the channel is set, it is necessary to select CATV. The television and the DVD recorder of the ground digital-ready should note it because there is something that doesn't correspond to the low-pass band-pass transformation.
Transformer modulation method
The transformer modulation method is a method that is modulated again after the CATV company receives it once with the tuner of the ground wave digital broadcasting and transmitted with the CATV channel. A tuner that television, is tuner that can receive the CATV channel or special is necessary. It is chiefly a reception with an analog tuner.
Broadcasting the high-definition television of the ground wave digital broadcasting can be seen only in a standard image quality. Naturally, recording becomes a standard image quality, too. Moreover, a special tuner for the number is necessary when there is a television even for how many. If it is a rental, the charge is necessary.
Frequency used with CATV
The frequency used with CATV is as follows. The same frequency pass-through method is transmitted like UHF signal.
- VHF(L) (VHF low-channel)
90-108MHz 1-3ch (For three channels for Television Broadcasting)
- MID (middle-channel)
108-170MHz C13-22ch (For ten channels only for CATV)
- VHF(H) (VHF high-channel)
170-222MHz 4-12ch (For nine channels for Television Broadcasting)
- SHB (super high band channel)
222-470MHz C23-C63ch (For 41 channels only for CATV)
- UHF (UHF channel)
470-770MHz 13-62ch (Use it by 50 channels and the same frequency pass-through methods for Television Broadcasting)
Frequency of conversion pass-through method
When the one of an old standard is used for the cable and the equipment, a high frequency like UHF might not be able to be used with CATV. In this case, the ground wave digital broadcasting is transmitted by using a frequency band that is lower than not UHF but this in the frequency conversion pass-through method.
Method of selecting CATV booster
It is necessary to insert the CATV booster before it distributes it and, in this case, to make amends for the distribution loss by 4-8 distribution from CATV to each room because the electric wave weakens considerably. In this case, the CATV booster for the descending amplification is used.
When BS and the CS signal are mixed with the same coaxial cable, the CATV booster for the descending amplification that amplifies BS and CS is used. It will be easy for the choice of the model that can feed power to use the plus 15V also for the BS antenna.
The descending regeneration of signals of the CATV booster uses the one corresponding to 70-770MHz. Because this bandwidth is amplified almost flatly, it is the best for the amplification of the CATV signal and the ground wave digital broadcasting. Then, it is necessary to note it for CATV because it is not, and the booster for U/V/BS/CS for usual antenna amplification doesn't amplify the CATV channel.