Lowering the input frequency for a frequency doubler using a single 4069

Thread Starter

teliocide

Joined Sep 26, 2013
56
I downloaded the posted cro.zip file. It extracted and played correctly. It was made using 7-Zip.
There seemed to be no provision to upload video as defined by files types.
Its just an mp4 video... a screen capture of the pc oscilloscope.

Currently power and modules and cro are connected with alligator leads. I will try replacing these with soldered wiring.
This circuit has 3 components only AAAAHHHHH!
I have assembled things with 100's of components and They worked.

Thanks for your patience and perseverance.

Greg
 

Thread Starter

teliocide

Joined Sep 26, 2013
56
That seems to be a rather complex circuit for frequency doubling.
But you should be able to get it to work at a lower frequency by increasing the value of capacitors C1 and C2.

Below is the LTspice simulation of a simple frequency-doubler circuit using one CD4070 XOR gate, one resistor, and one capacitor.

View attachment 150507
I have been quiet as I have been learning ltspice.........
Where do I go to get the ltspice models for the CD4070 and the 4069??

Thanks
Greg
 
Last edited:

crutschow

Joined Mar 14, 2008
23,736
Where do I go to get the ltspice models for the CD4070 and the 4069?
See the attached files.
Place the two .lib files in C:\Program Files\LTC\LTspiceXVII.
This include both CD4000 and 74HC00 models.

Uzip the Digital.zip file and replace your Digital folder in C:\Program Files\LTC\LTspiceXVII\lib\sym with the Digital folder from the zip file (make a backup of your Digital file first).

When you use these you need to add a Spice Direction [ key S] of ".lib CD4000_v.lib" or ".lib 74HC_v.lib" to the simulation.

Also you must have a digital supply voltage with its net labeled Vdd.
(My simulation in Post #4 didn't have a Vdd source, but it used a slightly different CD4000.lib)
 

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Thread Starter

teliocide

Joined Sep 26, 2013
56
Thanks you again,

For some reason my installation of ltspice puts the library files in both the program and the documents folders but only addresses those in the Documents folder.
This a default installation on a WIN7 PC.
I put your files in both locations.
I added the Spice Direction to the cd4077b and it appears to be working.

Run and I get the error "unkown circuit node Vdd" .... as I have not set this up.

I have spent a long time running in google-circles trying to understand .net and and create the Vdd.

Still at a complete loss.
 

crutschow

Joined Mar 14, 2008
23,736
I have spent a long time running in google-circles trying to understand .net and and create the Vdd.
Press F4 when in the schematic window.
Type Vdd in the space.
Click on OK.
Attach the Net Name to any wire coming from the power source you want to use for the digital logic.

It also can be done from the Edit command list.
 

Thread Starter

teliocide

Joined Sep 26, 2013
56
Thanks for the directive..
All sorted and works.... thank you
I have it working at both ends of the frequency range I require.
Just trying to tweak the RC values to get the best ON period as a balance between too short or too long with respect to the frequency.
20Hz working.jpg

160Hz working.jpg

I have had a re-build of the 4077B circuit. Works -YES functions-NO
working mess.jpg

Messy and weird. For some reason this only works with a VCC of 1.5-1.8V. Above this voltage it just collapses.

This Sound card oscilloscope is pretty close to useless.
It is impossible to shield it from interference and the channels are not separated.
Lacking the capacity to see clearly what is happening, in essence, is nothing more than a good approximation to a complete waste of time
So I have ordered a Hantek 6022BE USB Oscilloscope.

Thanks again
Your perseverance is appreciated
 

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