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actually the audio signal i used was amplified in a first stage CE amplifier and the decoupled output was applied to Q1 base hence it's also a multistage amplifier . i wonder if the problem is related to the position of the tank circuit or to the oscillator type .. ?
oh sorry i forgot to say that i used 9V battery instead of 6 V in my circuit and i got around 6v p-p in the oscillator output. may be it has something to do with the resistors ?
please take a look at the following AM tr :
http://english.cxem.net/radiomic/bug15.php
as said in the last row it does not need an antenna or using just 30 cm will increase the range . does this imply that the output signal power in this circuit is larger than that of my circuit ? what do u...
I have built an AM transmitter using colpitts oscillator in the following link:
https://commons.wikimedia.org/wiki/File:NPN_Colpitts_oscillator_base_coil.png
and i was applying the decoupled audio signal to the base of Q1 and the values for C1, C2 and L were 1n , 10n , and 50uH respectively...
so can this low signal be applied to any CE amplifier and be demodulated ? let's say a voltage divider CE amlifier with high gain , will it demodulate and amplify the 5 mV AM signal ?
plz take a look at the following link :
**broken link removed**
the last 3 lines in the first paragragh say :
"however the input signal levels at RF are tiny, typically 50uV appearing across the coil being amplified by Q2 and being about 5mV RF across the 2k2 load resistor ".
my question...
That's what i am asking about , the bypass capacitor in not included in the diagram , i think it must be connected between the output and the ground to remove the carrier pulses , i see that the 220 n capacitor does not perform this task since it's connected in a form of hypass filter , not...
the base - emitter junction would work as a half wave rectifier i think , not as envelope detector . still dont understand how it works , can u give a little more explanation ? thnx
can anyone explain to me how Q3 works as AM demodulator in this circuit ??
**broken link removed**
i don't see that it works as an envelope detector , it doesn't have any capacitor in its output , so how does it work ?
thnx
Hi ,
I've an old PC USB speakers , and i want to generate an audio signal to be used in a RF transmitter ,
can i cut the jack wire and apply it directly to the circuit , or i need to connect a capacitor ?
The speakers jack wire has two colors yellow and white , does it matter which one to use...
AM modulator question ?
**broken link removed**
I tried to generate AM wave using that oscillator (fo is about 900 KHz) , I've applied 10kHz , 2v peak sinewave from a function generator connected between the transistor emitter and the ground (parallel to Re) , i got an AM signal but with very...
I want to generate an AM modulated signal with colpitts oscillator :
**broken link removed**
can this be performed by connecting the audio signal (mic or whatever) between Rb2 and the ground ? if not then what is a good way to do AM modulation ?
thanx
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