Hello all i have to generate a waveform as in the attached image .Does anyone have any idea/Schematic?
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Does the burst have to be started at midpoint, eg. synchrous to trigger to start
the burst ?
When burst is off how many db down does 27 Mhz have to be from burst peak ?
Do bursts have to drive 50 ohms ?
Basically you gate an oscillator to do design. You can either gate the signal thru
a switch, or ground it in a voltage divider. 27 Mhz, my guess, probably wants to
come from a xtal oscillator....?
Regards, Dana.
Yes i want to design a pulsed electromagnetic field device this is my purposeHow do you intend to use this waveform? It's a pulsed radar signal. Do you have experience in RF?
i am a begginer in RF field.How do you intend to use this waveform? It's a pulsed radar signal. Do you have experience in RF?
Please post your schematic. Without that, we don't know exactly what you are talking about.these original and Switching signal
Unless you gate the actual oscillator. This would achieve complete carrier supression.Please post your schematic. Without that, we don't know exactly what you are talking about.
No RF switch is perfect. How much attenuation or output voltage do you require for the "off" state?
ak
True, but ...Unless you gate the actual oscillator. This would achieve complete carrier supression.
True, but ...
Given the information in post #6, and the startup time of a crystal oscillator to come to stable amplitude and frequency compared to the 2 ms output window, I think a switch circuit is a better approach.
ak
Unless you gate the actual oscillator. This would achieve complete carrier supression.
True, but ...
Given the information in post #6, and the startup time of a crystal oscillator to come to stable amplitude and frequency compared to the 2 ms output window, I think a switch circuit is a better approach.
ak
Thanks for the time and response i just want turn on and off the 27MHZ signal throgh 555 timer i need a pulse rate of 1000 pulses per second and the pulse on duration should be 100 micro seconds i do not have to tranmit he wave just i need a pulsed magnetic field.I have craeated 1000 pulses from 555 timer but do not have any idea how to switch the 27MHz on and off as per my requirementYour schematic shows you driving base of NPN directly, with no current
limiting or proper bias, from 555. That would burn out the NPN base junction
for sure.
You are trying to gate RF, the 27 Mhz signal, so to get effective off performance
you really should think about a pin diode type switch arrangement, links in earlier
posts. Of course if you do not need a lot of suppression of 27 Mhz when gate is
off you can consider some alternatives, eg. open collector switches to ground
diverting signal to ground.
Curious, what is the series LC trap on NPN collector to ground for ?
Regards, Dana.