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double-pi low pass filter

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This is a double pi filter.
 

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hi

this is the tv modulator circuit using MC1374
 

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I expect they call this a double pi filter too.
 

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hi

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...
 
hi...about the low pass filter... i wonder what are the differences of hartley oscillator and colpitts oscillator... what i've learned are all theory, when i come to practical part i am really shocked..have to design the circuit by myself, the value of the components...
how to calculate the value of the C and L?any suggestion?
 
can replace by pll circuit?

hi hi.can i replace the low pass filter with phase locked loop? is it better?
 
The low pass filter is there to filter out the harmonics from the output.
No you cannot replace it with a phase locked loop.

JimB
 
Re: hi

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...
The filter in the schematic is not inside the chip. You have to add all the discrete components around the chip, as shown in your schematic.
 
hi

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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Re: hi

8cube said:
this is also a double pi filter? how to choose a low pass filter? wat is the calculation? really blur now
The filter is already designed for you - L3, L4, C11, C12, and C13. Why do you think you need another filter?
 
hi

cos i think that is just for modulator...
after the signal come out from modulator, need to pass through a low pass filter to remove the distortion , is it correct?
 
Re: hi

8cube said:
after the signal come out from modulator, need to pass through a low pass filter to remove the distortion , is it correct?

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.
 
Re: hi

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?

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.
Amen. :D
 
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