Hi! Manuel,
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It is not that we missed your work in fact we looked at it with great interest. I was interested in a PLL design for VFO for long. My opinion by using a PIC we complicate things.
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Now a PIC and 145170 combo is as simple / complex as PIC and AD9851.?Since we can get the DDS chips as free samples hence a DDS design appears more practical.
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This does not means that a PLL is no viable , I have been working on a dicreet design using 74192 chips with 10Khz ref pulling. The same comcept can be implemented upon a MC145151 as done in Multipig design.
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You are right about high ft IF limitations . As per simulations done by our Prof Rob there appers roll off of frequency due to highly negative feedback nature of amp designs. I am evaluvating results of? high Ft BJT devices. Maybe one back this design would evolve into a basic building block towards a multibander.
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73
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Rahul VU3WJM
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eb7hpm wrote:
I want to contribute the comunity with my work and that you not
missed the earlier post. I don't want recognition, I only want to
ear coments about the circuit from more experienced hams, I am
computer engineer!! ;-). I was looking for a good, simple and easy
design in the Internet but I not found it, It is the reason I make
the design and program to drive the PLL.
I don't know the designs of VK6BRO Richard Hosking, but i think they
are complex. I will publish this work in the huff-puff group.
P.D: My BITX with a FI of 32MHz and VCO of 53MHz is working, but it
is very bad, with BF495 transistor, i only output 1 Wat, and the PLL
show some inestability. The VCO, BFO and filter works at 32MHz. I
think the bilateral amplifier don't work at 32MHz. I miss something?
73s
Manuel
EB7HPM/EC7ALV
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