double-pi low pass filter

8cube said:

what do you mean by a filter and a half? the filter in the schematic is inside the chip ... the output of the chip will connect to a low pass filter.. that is , the double pi low pass filter...

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8cube said:

this is also a double pi filter? how to choose a low pass filter? wat is the calculation? really blur now

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8cube said:

after the signal come out from modulator, need to pass through a low pass filter to remove the distortion , is it correct?

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David Bridgen said:

8cube said:

after the signal come out from modulator, need to pass through a low pass filter to remove the distortion , is it correct?

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The i.c. MC1374 is the modulator.

The signal comes out of pin 9.

The components which I highlighted in my 2nd post (L3, L4, C11, C12, and C13), and mentioned again by Ron H in his last post, form the low-pass filter which you are so anxious to locate yet so reluctant to accept.

It attenuates the harmonics and other high-order modulation products.

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