Wednesday, April 23, 2014

S-VHS cable

When we talking about S-VHS cable, we need to know the S-VHS, so what S-VHS is? I would like to give you a general account of S-VHS below:


S-VHS is short for super video home system; this is a new model developed by JVCKENWOOD Corporation (Abbreviation: JVC) in succeeding of VHS by other companies, the new model have a characteristic of high resolution, high fidelity, 20Hz-20KHz’bandwidth, 90dB above dynamic and signal-to-noise ratio. On a par with LD’s image and CD’S sound, S-VHS becomes indispensable equipment for all the Hi-Vi Lovers.

S-VHS have an inferior image quality than DVD’s, but 500TVL’s resolution for most TV can’t achieve, and also you can hardly judge the image quality difference with our naked eye either it played in S-VHS or DVD. Furthermore, the forward compatibility means all VHS tapes can be played in S-VHS player, but it’s not the other way around.
 
Developed on the basis of VHS, S-VHS greatly improved the performance for the compatibility with VHS, and below ,I need to lay the details concerning the electronic circuit, magnetic heads, tapes  which have a thoroughly improvement.
     
1,The videos Y signal for S-VHS expanded upwardly to the phase of 7MHz, frequency deviation improved to 1.6MHZ,effective bandwidth for brightness improved to 5MHz comparing with VHS’s 1.0MHz and 3.2MHz.According a general calculation for resolution that 1MHzs bandwidth equals 80TVL, we can know that VHSs resolution is about 250TVL,S-VHS reached to 400TVL above. That’s huge improvement for image quality.

2, after the improvement of bandwidth, the crystalline magnetic head is no long adapt to eddy current loss and the clutter interference by high frequency, so JVC redeveloped amorphous magnetic heads which was laminated by several thin-films to improve insulation and reduce eddy current. Quite effectively improved highlow frequency performance, and bettered the chroma frequency signal in the lower end of the spectrum, which greatly improved the color saturation.

3, In order to reduce interference between brightness (Y) signal and color (C) signal, S-VHS video recorder handling Y/C signal separately on recording and playing, placing the Y and C signal in a better functioning  condition.
    
4,To adapt the needs of high sensitivity of new magnetic head of broadband, using chromium and Iron oxide Fe2O3 for high magnetic saturated coating with a thickness of only 0.5μm ,greatly improved thermoremanent  magnetizationTRMand coercive force, in this way, the signal recording improved.
  
5, during the process of signal transaction, time-constant is utilized to limit amplitude and impose accentuation, which, in a way, greatly reduced the edge noise of image. The noise in the nonlinear region is also repressed by synchronizing time-constant with inputted signal level.

6,With an audio frequency response of 12 KHz, its not enough for VHS recording a high fidelity program. 33.35mm/s’ tape speed, relatively lower than cassette tapes 47.6mm/s; Improving the tape speed is the only way to improve frequency response. Introducing the specialized Hi-Fi sound accompaniment magnetic head in the high speed rotary drum can make magnetic heads relative tape speed running 5.8m/s, which is 170 times higher than static sound accompaniment magnetic head, can achieve 20KHz’ frequency response recorded by rotary magnetic head, if the recording in EP Mode(1/3s normal speed-slow speed), still  a record of 20KHz  maintained ,which makes high fidelity sound accompaniment come true.
7, Based on different characteristics of S-VHS sound accompaniment frequency modulation and whiteness’s frequency modulation. Deep oriented recording method adopted to record the accompaniment sound signal in a blank tape before recording the image signal on the surface, improved the accompaniment standard and efficiently used the tape.

Now, let’s come back to S-VHS cable, while running S-VHS machines properly, a cable connecting between devices is necessary. A brief and simple definition for S-VHS cable is a kind of wire connecting S-VHS devices. Anyway, you can easily know S-VHS cable after you know what S-VHS is. Good quality cables can guarantee S-VHS’s sound and image quality; make S-VHS’s advantage prominent. So don’t lose your S-VHS’s advantage by choosing a good quality cable can be never ignored while you buy the machine but the cable separately.

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