Hello!

I'm trying to simulate an RF filter & amplifier for the 60Khz radio time signal coming from Fort Collins, CO. using LTSpice.

https://www.burningimage.net/clock/2007/10/23/sensitive-60khz-receiver/

This website shows the schematic that I've been trying to simulate.

Any help is much appreciate it!

 

So are you having a problem with the simulation?

One error I see is that the input to op amp U2 has no dc path to ground, which is necessary.
Add a resistor to ground, in parallel with C11 (try 100kΩ).

Also R3 and R7 are very low values.
I would increase those and their respective feedback resistors by at least a factor of 5 (which will require reducing the feedback capacitors by the same factor).

 

Welcome to AAC!
Your sim runs, albeit slowly. What help are you looking for?

 

Welcome to AAC!
Your sim runs, albeit slowly. What help are you looking for?

So, I was hoping to see a 60khz sine wave with an amplitude in the Volts range as my output, but i get DC at mV, my understanding is that L1 & C1 are going to give me 60Khz and the rest of the circuit will amplify and filter out any spurious signal, resulting in my output being a pretty 60khz sinewave.

this file is a colspitt oscillator that I did a couple of semesters ago, and it works flawlessly, my lc tank is setting the frequency and the rest of my circuit amplifies my signal, even before the first BJT, I get a sinewave in the uV range, and that's not the case in my other simulation. I put the probe in the LC tank and I see DC, it's not oscillating at all

 

I did some work with that receiver about 3 years ago. It is not a 60 kHz amplifier. It filters out the carrier. At least that is what my simulation did.

 

I did some work with that receiver about 3 years ago. It is not a 60 kHz amplifier. It filters out the carrier. At least that is what my simulation did.

Yes, it outputs the envelope of the input.

 

See


Add my library.
See #25
https://forum.allaboutcircuits.com/threads/amplify-high-frequency-signal.150692/page-2
See #23 - #30
https://forum.allaboutcircuits.com/...v-dc-400-ma-linear-power-supply.150587/page-2

 

If you feed it with a continuous sinewave you will only a DC level out. You need something like the real time signal - 900ms signal and 100ms of no signal.

Also, as already stated, you need a resistor across C11 otherwise it will never discharge

 

In my simulation before building it, I just used a frequency sweep to see how it behaved as a filter/amplifier.