19-04-2012, 12:34 AM
Hi Lawrence,
I've been sitting here with pencil and paper trying to produce a block diagram to figure out the overall idea: and I'm sorry, I'm stuck!
One thing does cross in my mind: since your detector has a tunable bandwidth of 500 kHz, surely this means that your 3 MHz I.F. must have a bandwidth of from 2.75 MHz to 3.25 MHz, i.e. centred on 3 MHz ? Therefore, irrespective of your method of deriving the local osc. freq., surely that means, in turn, that the necessary pre-selection before the mixer needs to have a selection of tuned circuits similarly tuning in 500 kHz segments. And that is a lot of L/C ccts. to cover the whole S/W spectrum !
It's obvious I've misunderstood things
So if you could send an attachment with a block diag. explaining your idea, I would be much obliged; thank you.
Cheers,
Al.
I've been sitting here with pencil and paper trying to produce a block diagram to figure out the overall idea: and I'm sorry, I'm stuck!
One thing does cross in my mind: since your detector has a tunable bandwidth of 500 kHz, surely this means that your 3 MHz I.F. must have a bandwidth of from 2.75 MHz to 3.25 MHz, i.e. centred on 3 MHz ? Therefore, irrespective of your method of deriving the local osc. freq., surely that means, in turn, that the necessary pre-selection before the mixer needs to have a selection of tuned circuits similarly tuning in 500 kHz segments. And that is a lot of L/C ccts. to cover the whole S/W spectrum !It's obvious I've misunderstood things
So if you could send an attachment with a block diag. explaining your idea, I would be much obliged; thank you.Cheers,
Al.
