how to create a 1MHz sine wave 0.4Vpp with short gaps in between?

Thread Starter

Abhishek Y

Joined Mar 24, 2016
5
Hey, I need assistance in my project to create a 1MHz sine wave of 0.4Vpp with short gaps of sometimes 10us and other 20us. I need it as an input to my project. Please find the attached photo of the LTspice simulation. I need it as an input to my hardware.
 

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RichardO

Joined May 4, 2013
2,268
Old analog function generators (such as from Wavetek) could do this by gating one generator from another one. With any luck, you can find some of these to use.

The way they did this was to first generate a triangle using an integrator and hysterisis switch. This is similar to how a 555 timer works if the capacitor is charged and discharged from current sources. Then they clamped the integrator when it reached the desired phase (while it is going in the correct direction of voltage). The triangle wave was converted to a sine wave using a nonlinear shjaping circuit.

This might be done with a generator that uses direct digital synthesis as well. That would require more thinking on my part...
 

Thread Starter

Abhishek Y

Joined Mar 24, 2016
5
Old analog function generators (such as from Wavetek) could do this by gating one generator from another one. With any luck, you can find some of these to use.

The way they did this was to first generate a triangle using an integrator and hysterisis switch. This is similar to how a 555 timer works if the capacitor is charged and discharged from current sources. Then they clamped the integrator when it reached the desired phase (while it is going in the correct direction of voltage). The triangle wave was converted to a sine wave using a nonlinear shjaping circuit.

This might be done with a generator that uses direct digital synthesis as well. That would require more thinking on my part...
Thank you RichardO I'll see to it. But any other method you have any idea.
 

#12

Joined Nov 30, 2010
18,167
any other method you have any idea.
You are trying to make a gated oscillator, an oscillator and a gate circuit. Make an oscillator and turn it on and off with any of a dozen methods.
You can stop the oscillator or stop the signal in a circuit after the oscillator.
 

Papabravo

Joined Feb 24, 2006
12,697
You should be able to use an analog switch as a multiplexer to switch between your signal source and a passive pulldown to GND. Would you catre to share the circuit you used for the simulation with us. It might clarify what you are trying to do. We should be able to eliminate what looks like an exponential decay between the bursts.

EDIT: Yeah -- what #12 said.
 

ScottWang

Joined Aug 23, 2012
6,843
Here is the block diagram, you can according the block to modify to close your goal and describe some more details, when the pictures more clear then you will more quick to reach your goal.

1MhzSinewaveWith10-20uSGap_Abhishek Y_ScottWang.gif
 

Alec_t

Joined Sep 17, 2013
10,604
For an RFID tag won't a gated 1MHz triangle wave, or even square wave, suffice? Simpler to generate than a sine-wave.
 
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