Your Super-regen has been changed so much that it might not have a quench oscillator anymore. Maybe changing a capacitor stops it from working.mstechca said:I was again tinkering with my superregen (a.k.a. Audioguru's "TOY" :lol: )
I was wondering, could I calculate bandwidth based on the incoming frequency and the quench frequency?
if so, is there a simple equation for it?
Maybe this is the reason why I can pick up a TV signal when I adjust the quench oscillator capacitor to one value, and I can't pick up the same signal when I adjust the capacitor to another value.
that is impossible :lol:Your Super-regen has been changed so much that it might not have a quench oscillator anymore.
so bandwidth doesn't matter when it "slope-detects" the signal by tuning the receiver's peak to one side of the transmission.
Your circuit doesn't have a quench oscillator, instead it is a regen receiver without a manual sensitivity control. The Techlib article that it comes from calls it a regen-receiver, not a super-regen. A super-regen uses its quench oscillator to make its sensitivity adjustment automatic.mstechca said:I don't know of any superregen without a quench oscillator.
The FM sound of a TV station has a bandwidth of only 75kHz at max modulation in mono. The AM modulated picture has a bandwidth of nearly 6MHz.A TV station requires about 6Mhz of bandwidth right?
No they don't, your circuit is just an RF oscillator with a fixed bias control.I still think the capacitor on the far right and the pull-up resistor make up the quenching frequency.
I have seen many super-regen circuits and they all have a resistor and capacitor from the emitter to ground to form a relaxation "squegging" oscillator. MStechca's circuit doesn't have any parts to make a relaxation oscillator.Ron H said:I ran a sim on Mstechca's circuit, and it does squegg at about 35kHz.
Ron, what software are you using to simulate my circuit?I ran a sim
Look in Google for Super-regen and you will find articles about how they work.mstechca said:why is a relaxation oscillator necessary?
Yes, to avoid aliassing beat frequencies when the desired signal is more than half the squegging oscillator's frequency. You will have problems with the 23kHz to 53kHz FM stereo subcarrier and the FM SCA "storecasting" signals if the squegging oscillator's frequency is less than about 140kHz. Data transmission will also be upset if the squegging oscillator's frequency is too low.If later, I wanted high bandwidth, doesn't the oscillator need to be high too?
I already knew that part.Since the transistor has positive feedback by the capacitor between the collector and emitter
At home, I use LTSpice/SwitcherCADIII.Ron, what software are you using to simulate my circuit?
Yep. R1 and C1. Remember that C1 is also an RF bypass cap. I changed R1 from 10k to 50k, keeping the R1*C1 time constant at 33us, and the quench frequency changed from about 60kHz to 160 kHz. You don't have a scope, do you? As you can see from this experiment, it is difficult to predict the frequency.mstechca said:Aren't there two components somewhere in your circuit that make up 150Khz for the quench?
If I know the components for sure, then maybe I can just switch the values instantly, and everything will function better.
that must be the base-bias resistor.
In terms of math, how does the time constant of 33us relate to the quench frequency. I don't understand how you got 60 Khz and 160 Khz.....keeping the time constant at 33us, and the quench frequency changed from about 60kHz to 160 kHz.
No.You don't have a scope, do you?
I just explained that I don't know how to analyze it. I just chose 33us because that was the approximate R1C1 time constant in my first sim. My point was that you can't easily predict the quench frequency by knowing the time constant.mstechca said:that must be the base-bias resistor.
In terms of math, how does the time constant of 33us relate to the quench frequency. I don't understand how you got 60 Khz and 160 Khz.....keeping the time constant at 33us, and the quench frequency changed from about 60kHz to 160 kHz.
Is the 60Khz and the 160Khz the numbers the sim gave you, based on the R1 and C1 you provided, or is there a way I can figure these numbers out.I got 60kHz and 160kHz by simulating the circuit with
1. R1=10k, C1=3.3nF (R1C1=33uS)
2. R1=50k, C1=660pF (R1C1=33uS)
Please read my previous post. I already answered this question.mstechca said:Is the 60Khz and the 160Khz the numbers the sim gave you, based on the R1 and C1 you provided, or is there a way I can figure these numbers out.I got 60kHz and 160kHz by simulating the circuit with
1. R1=10k, C1=3.3nF (R1C1=33uS)
2. R1=50k, C1=660pF (R1C1=33uS)
I'm not implying that this circuit is a good superregen receiver. I am just pointing out that, in simulations, it does squegg. I would be very surprised if a hardware version did not. I have seen plenty of sims that didn't oscillate when they should, but the opposite case is highly unlikely.audioguru said:I didn't think that an "ordinary" oscillator from a simple FM transmitter would have squegging oscillation. I see that if it is overbiased so that its RF oscillations are mainly with the transistor saturated then the transistor would gradually conduct more and more until its operating point won't allow RF oscillations anymore. I think that the supply's internal resistance in series with R2 is important as well.
Most super-regen circuits use a bypassed emitter resistor as a peak detector so they set the squegging frequency, allowing for an adjustment of the transistor's base bias current to set its sensitivity.
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