Pdrummer
Eager Beaver
Joined: 19 Mar 2006
Posts: 17
Location: NC |
| signal generators |
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I'm not sure if i'm right but aren't signal generators in mixing consoles are what produces the signals in all the channels, if so, how do they work, i've always been wondering how it works. |
Wed Jan 10, 2007 4:38 pm |
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wailingalleycat
Forum Manager
Joined: 07 Oct 2003
Posts: 694
Location: Jersey C.I (UK) |
| Tone Gen |
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The only signal generator i can think of in a mixing console is just a section to produce tones and pink/white noise for testing output busses and speakers etc.
is this what you mean?
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If In Doubt...Hit It With a Hammer, If Still In Doubt... Find a Bigger Hammer. |
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Wed Jan 10, 2007 5:37 pm |
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amitbarde
Forum Moderator
Joined: 24 May 2006
Posts: 79
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Yes...Paul's right!...all the signal generators do is produce "test tones" whatever they may be....typically....white/pink nose and probably a 1khz sine wave. All these are used for testing equipment......they DO NOT produce any signals in the channel....whatever thechannel gets is what is coming into it via a mic/di etc and through it's pre amp. |
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Wed Jan 10, 2007 5:55 pm |
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conquistadore
Forum Moderator
Joined: 03 Aug 2004
Posts: 514
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| Routing |
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But on more 'advanced' digital consoles it should be possible to route the oscillator's out put to any channel. But real requirement would be on buses and outputs. |
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Thu Jan 11, 2007 5:27 am |
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conquistadore
Forum Moderator
Joined: 03 Aug 2004
Posts: 514
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How does it work?
On analogue consoles it would typically be Oscillators that generate these test tones. I guess Amit should be able to give you a better picture? |
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Thu Jan 11, 2007 5:29 am |
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Pdrummer
Eager Beaver
Joined: 19 Mar 2006
Posts: 17
Location: NC |
| oh |
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Yeah, I just saw or heard something about signal generators with mixing consoles, ok, then I was right all along, then the potentiometer(gain) really does increase the voltage in the circuit all the way to the microphone cable, it would have to, it is one circuit. Unless I'm wrong. |
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Thu Jan 11, 2007 6:01 pm |
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conquistadore
Forum Moderator
Joined: 03 Aug 2004
Posts: 514
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| Re: oh |
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quote:
Originally posted by Pdrummer
Yeah, I just saw or heard something about signal generators with mixing consoles, ok, then I was right all along, then the potentiometer(gain) really does increase the voltage in the circuit all the way to the microphone cable, it would have to, it is one circuit. Unless I'm wrong.
Not really. The gain knob does not increase the voltage all the way through the mic cable. A normal microhpone emits a very low signal - in micro volts, that passes into the cable and then into the Mic input of the console. But this voltage is too low to work with. The industry standard for a line level signal (a signal that is strong enough to work with) is 1.23V. So you can see the difference - the the voltage needs to be raised from a micro volt value to a volt value. What the gain knob does is that it increases the voltage of the signal to 1.23V (provided your gain structure follows the Unity Gain rule - 0dBu) and then passes that signal on to the rest of the circuitry (inserts, EQs, Auxes, Faders.etc). It
does not
increase the voltage in the mic cable itself. |
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Fri Jan 12, 2007 6:08 am |
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amitbarde
Forum Moderator
Joined: 24 May 2006
Posts: 79
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quote:
Not really. The gain knob does not increase the voltage all the way through the mic cable. A normal microhpone emits a very low signal - in micro volts, that passes into the cable and then into the Mic input of the console. But this voltage is too low to work with. The industry standard for a line level signal (a signal that is strong enough to work with) is 1.23V. So you can see the difference - the the voltage needs to be raised from a micro volt value to a volt value. What the gain knob does is that it increases the voltage of the signal to 1.23V (provided your gain structure follows the Unity Gain rule - 0dBu) and then passes that signal on to the rest of the circuitry (inserts, EQs, Auxes, Faders.etc). It does not increase the voltage in the mic cable itself.
Varun's absolutely right.
But what i don't really understand pdrummer is that what have the gain knobs got to do with signal generators?....Please let me know if i'm missing something here 
....Anyway as far the oscillators which generate test tones....well you could have different types of oscialltors generating different test tones. You have the "traditional" oscillators which work based on a "tank circuit" (a circuit which basically contains an indductor and a capacitor). A basic way to describe the working of these circuits would be to say that there is a constant change of polarity that takes place which allows the oscialltions (which over here would be the movement of the electrons through the circuit...which can only happen if there is a change of polarity for every cycle)....
The other type of oscialltors that are quite popular are the crystal osicllators. These kinds oscillators are said to provide a greater accuracy, hence prreffered over the traditional tank circuitry.....there's really not much else i can tell you about oscillators. The other forms of signal generators a console would have, as has already been said before, are white and pink noise generators.
....and you probably already know that white noise is a wide band noise that has equal energy per octave while pink noise is basically filtered (passed through a low pass filter if i'm not mistaken) white noise that has equal energy for every frequency. |
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Fri Jan 12, 2007 11:42 am |
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conquistadore
Forum Moderator
Joined: 03 Aug 2004
Posts: 514
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| White + Pink Noise |
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quote:
Originally posted by amitbarde
....and you probably already know that white noise is a wide band noise that has equal energy per octave while pink noise is basically filtered (passed through a low pass filter if i'm not mistaken) white noise that has equal energy for every frequency.
Correction - White Noise has equal energy across all frequencies whereas Pink Noise has equal energy per octave. |
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Sat Jan 13, 2007 7:07 am |
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