| Author |
Message |
    
Bigbob
| | Posted on Friday, October 18, 2002 - 6:36 pm: | 
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Could you explain in short the differences of a bfo,vfo,and vco,I do know what a voltage controlled oscillator is but what are the other two?thank you very much,Bigbob. |
307
| | Posted on Sunday, October 20, 2002 - 11:59 am: |
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Well , I am no expert however a VFO is a Variable Frequency Oscillator used mainly to change an Analog Frequency such as a Siltronix model 90 VFO. It replaced a crystal.
A VCO is a Voltage Controlled Oscillator that normally drives the loop in a Phase Lock Loop (PLL) and is highly accurate and locked to a reference frequency.
A BFO is a Frequency Oscillator that is used in "NON" sideband receivers to act as a way of beating the AM signal (nulling it) so a sideband signal can be understood within the audio.
Comments?
307 |
Taz
| | Posted on Sunday, October 20, 2002 - 1:21 pm: |
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No expert??????????????
Have you heard the saying,
He who knows nothing thinks he knows everything.
He who knows everything thinks he knows nothing.
Taz |
Bigbob
| | Posted on Sunday, October 20, 2002 - 1:03 pm: |
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Thank you very much,307. Bigbob |
Ss8541
| | Posted on Sunday, October 20, 2002 - 10:11 pm: |
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bfo stands for beat frequency oscillator. it is for ssb and cw. your clarifier in your cb/10mtr rig controls what is mixed with the bfo. and how about it, the vco that you asked about is what the clarifier controls. it changes the frequency of the vco as it is turned.
in cw and ssb modes, the 10.695mc carrier oscillator runs in rx and tx(it only runs in tx mode for am and fm). in rx mode it is the bfo for the rxed cw or ssb signal. the incoming rx freq is 'beat' against the freq of the bfo(10.6925 or 10.6975mhz depending on if your are in usb or lsb). the resulting freq from the 2 freqs 'beat'ing together is at the audio freq that will come out of your speaker.
basically just remember that the bfo is is used for cw and ssb to create the audio that you hear from your speaker. down and dirty, it puts the missing carrier for ssb back in at the rxer for demodulation to occur. |
Taz
| | Posted on Monday, October 21, 2002 - 12:48 am: |
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beat? like it takes a beating? haha |
Ss8541
| | Posted on Tuesday, October 22, 2002 - 11:02 pm: |
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yes, but if you 'beat' it too much you may go blind. so be careful when 'playing' with your bfo. |
Highlander
| | Posted on Thursday, October 24, 2002 - 7:59 pm: |
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Aw, it's no BFD if you beat your BFO! |
Bigbob
| | Posted on Friday, October 25, 2002 - 7:46 pm: |
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Hi I'm bobs neffyu I'M ten what duz BFD mean |
Bigbob
| | Posted on Sunday, October 27, 2002 - 7:45 pm: |
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I'm sorry guys I caught my nephyew on my 'puter he's pretty sharp.I had a long phone call with his parents on what to do about his question,and I should have locked the comp.when not on it.I don't have any kids of my own,and I never gave it a second thought,now I'm in the doghouse with his parents.I don't blame anyone but my self,y'know freedom of speech and all,it was totally my responsibility,again I apologise for the awkward situation.Bigbob(Robert) |
Ss8541
| | Posted on Sunday, October 27, 2002 - 9:42 pm: |
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RFLMAO! that was a good one bigbob. your right he probably didn't know what bfd is when abreviated since most 10yr olds today just come out and say it. but that is the perfect world we live in. you know, all kids being highly sheltered and kept from all evil until they reach 21. |
Bigbob
| | Posted on Thursday, October 31, 2002 - 7:47 pm: |
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Ss8541 you're a real piece of work,I think. |
Ss8541
| | Posted on Thursday, October 31, 2002 - 10:58 pm: |
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if you only knew me bigbob,,, you wouldn't be saying 'i think'. i can give a list of references if needed. |
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