WildCat FM /technical station. Black contents of WildCat FM "Fake or Real"?
The truth is confirmed. fake or real Suspicious information that flows plausibly in the world of mini-FM. Be like information on the lie without credibility. It is the suspicious world quite without relation though it is a technical thing said that the frequency modulation broadcasting electric wave will be used. It is no use of being said it is 20 years late. Is the Sreteo separation in mini FM transmitter true? Separation of FM transmitter mentioned in the world of mini-FM (right and left separation level) Do not you say indescribably easily by the story on Kican the problem's there might be in the catalog spec?!! Translation..understand..mini..FM..bulletin board..separation..improve..unknown..thing..say. It comes to want to doubt the real intention when it is possible to understand and it becomes -40 a dB if the value is -15dB--20dB. It comes to want to know as for the much more 50dB of ..doing.. - the circuit and the measurement condition of the modulation machine. However, it is in the transmitter of mini-FM that can achieve such a spec and I do not have the thing still meeting. -It is assumed that the sound of 100 was put in a left channel with the separation of 40dB. The sound that leaks to a right channel is 1/100. б...-It is 1/300 and it exists as for 50dB. To achieve an effective Sreteo separation in FM transmitter If an excellent as such MPX signal is not promoted, it is not possible to achieve it.
The following image is MPX signal of the transmitter typical of mini-FM.   Figure. 1a & 1b
Look at the whole of the signal disregarding the distortion, and there is no center line in the straight line. As for this, L+R and L-R are not balanced. It becomes and both cause the opposite phase deterioration in the separation a positive phase and exaggerated. The difference is clear if it compares it with the signal with a correct under. 
To achieve an effective Sreteo separation, the signal without the distortion is demanded.
However, another one cause of deteriorating the separation exists. It is a phase of the pilot signal and the MPX Sabcaria signal (subcarrier). Even if an excellent characteristic is obtained by the straight line in each frequency the line of the signal, the pilot signal and the subcarrier. A straight stereo separation characteristic is not obtained if the phase is not suitable. There is an equipment that controls the phase with PLL in an advanced professional machine, too. The image below is a measurement wave form of the pilot signal and the subcarrier of a correct phase.  
This measurement image adopts the method of recording in the manual of orban optimod 8100. The measurement image is displayed at the level recorded to compare images easily in the manual of orban. (Refer to 8100A1 Manual_Section_4/4 page. ) In the condition said that the phase of the above-mentioned pilot signal and the subcarrier is correct this time It makes it to the thing that limits to the mutation of the MPX signal, analyzes the Sreteo separation, and explains. In addition, when the phase shifts, the separation doesn't have the deteriorating thing to saying.
Under or exaggerated of the signal mutation sees the deterioration in the separation of how much ..whether invite it... The phase of the pilot signal and the subcareer signal completely each other destroys the adjustment of the balance of L-R. To make easily to see somewhat, the signal of Oshiro is greatly set. ...The modulation level is 100%, and is 1KHz, and L-CH. First of all, the ееее left is under, and the right is exaggerated from the separation 20dB.  
To the phase of the pilot signal and the subcareer signal even perfect each other The separation can be taken only by 20dB when shifting in the so much еее -. Figure. Obviousness is a guy compared with the image of 1a&1b.
Next, it is a separation 30dB. ееее  
Then, please look at the separation 40dB.ееее Desire that "Distortion" is slightly understood when seeing well, and slightness еее The signal with high accuracy is necessary to get the Parashon 40dB. Even if it is a little, the line cannot ..".. achieve the cod Parashon 40dB with". еее  
Control the signal wave form, and, in addition, the phase of the pilot signal and the subcareer signal in this manner The separation 40dB is not easily obtained with the equipment that cannot be adjusted.
In addition, in the state to exceed the separation 50dB еее -. The measured signal wave form almost becomes perfect in externals. 
Even if the phase of the pilot signal and the subcareer signal shifts Even if the balance of L-R collapses, the separation cannot be taken еее.
It is necessary to know what signal wave form is necessary to achieve a high separation in FM transmitter. What not to understand a correct signal wave form, a correct evaluation of FM transmitter cannot be done. People who do not understand well fiddle, turn a toy transmitter, and the separation is so on a roll of how. How though thought that Gotac can laugh that it is heard to arrange it. might?? Is suspicious information that flows to the world of mini-FM trusted?..... Let's trust an analytical of this content or leave the truth to your judgment. document of Saeki by WildCat FM /technical station. |
