Modulate One Output of CD4060 With Another

I have a CD4060 running off a 32.768KHz clock xtal. The 16Hz output is converted to a triangle wave. I would like to use this to amplitude modulate the 2.048KHz output of the same IC.

What is the simplest way of doing this that will preserve the triangular envelope and not just be a chopper?

Keven Grant

Reply to
kgrant
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Use a CD4049UBC, 2.048kHz to logic input (use any one section), triangle wave to VDD. Assuming the triangle is buffered with an op-amp or something. Use a weak pulldown resistor at the output, and buffer with another opamp. Or build the inverter yourself with a BSS84 and 2N7002. Or use a 74HCU1G04 (which apparently doesn't exist, but Toshiba makes an equivalent part), using a current-limiting resistor to the logic input, and keeping < 7V on any pin (you didn't mention what voltage you're using the CD4060 at).

Tim

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Reply to
Tim Williams

Modulation is multipication of the signals.

A triangle wave multiplied by a 0/1 square wave _is_ a chopper.

What do you expect to see as an output signal?

Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

probably an emitter follower.

| 2048Hz | |/c triangle -------| BC547 (or 2N3904 etc) |\e +-------> AM out | [1K] |

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Reply to
Jasen Betts

probably an emitter follower. BC547 transistor, triangle on the base, 2048Hz on the collector emitter has a 10K resistor to ground and is also output.

| 2048Hz | |/c triangle -------| BC547 (or 2N3904 etc) |\e +-------> AM out | [10K] | --+-- 0V

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Reply to
Jasen Betts

The 2048Hz squarewave within a 16Hz triangular envelope.

Kevin Grant

Reply to
kgrant

This wins the "simple" award. But, as someone pointed out, the traingle wave may need to be buffered.

I am runinning the CD4050 at 6-9V by the way.

Kevin Grant

Reply to
kgrant

It is the same as 16Hz triangle chopped by 2048 Hz square.

Use an analog switch or multiplexer, feed the triangle into the analog input (for a mux, use the other input at ground) and the square into the select/enable input.

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Tauno Voipio
Reply to
Tauno Voipio

yeah, actually that circuit doesn't work at all I forgot the base resistor. put 1M in series with the base and increase the 1K to 10K. That will also inrease the triangle input impedance to over 1M which probably means you won't need extra buffering.

sounds good.

| 2048Hz | |/c triangle --[1M]---| BC547C |\e +-------> AM out | [10K] | -+-

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Reply to
Jasen Betts

Lets see, there still is a question here.

do you want the 16Hz to control the amplitude of the 2048Hz, which would make it look like a amplified triangle of the 2048Hz with sloped peaks on the squares that follow the triangle?

Or, you want to see a smaller signal of 2048Hz riding on the wave of the 16Hz, maintaining constant level, even when the 16Hz is at base line with a real square wave peek?

Jamie

Reply to
Maynard A. Philbrook Jr.

If I'm not mistaken, I believe that kgrant clearly stated "amplitude modulate." ;-)

Reply to
RosemontCrest

Please provide more information on modulate; phase, frequency, amplitude, or other mode?

?-)

Reply to
josephkk

Thanks for asking. It would be the first instance you describe.

Kevin Grant

Reply to
kgrant

Take an analog switch, e.g. 4066, feed the triangle to the analog input and the sqaure to the enable input. You'll get the AM signal from the analog output. If the straight baseline bothers you, feed the result via a high-pass with a corner frequency around 200 Hz.

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Tauno Voipio
Reply to
Tauno Voipio

Thank you. I will try this.

Kevin Grant

Reply to
kgrant

is

amplitude,

oops, i missed that.

?-)

Reply to
josephkk

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