Turn the receiver off and then on at any time and temperature the bfo frequency is exactly the same.
Ceramic resonator bfo circuit.
All about circuits.
Nand gate u2b buffers the original unmodulated signal and its propagation delay ensures that its output is in phase with the output of u2a.
This circuit was used to stop all the bfo drift.
Perhaps they ll inspire me to build one hhny2all.
The input and output of the ceramic filter are tied together.
A ceramic resonator will not allow you to move the frequency more than a little.
3 used transistor bc548 9 volt supply voltage rf signal is produced with 455 khz ceramic crystal.
The last time i checked i didn t find it on the site but.
The filter s center terminal normally grounded is connected to the current limiting resistor.
455 khz tunable bfo circuit reply to thread.
I want to make a 455khz tunable bfo without any transformers based on the model on this page.
Discussion in general electronics discussion started by richard9025 feb 5.
This i found easier that trying to set it up with the frequency meter.
In conclusion has anyone any photos of a mini sized bfo circuit built with a ceramic resonator.
I built this because at the time i didn t have a signal generator that would perform am modulation.
I will try to get some photographs off to hans in the next day or so but life has been hectic over this weekend.
Oscillation is near 455 khz stable within a few hz.
Ceramic resonators ceralock lead type two terminal csbla series.
I taped a short length of wire from the output across the back of the circuit board and then adjusted the slug to give me the correct note.
The circuit is extremely stable.
Nand gate u2a is the modulator and provides a 100 square wave modulated signal.
Inverters u1d e along with ceramic resonator x1 form a stable 0 5 455 khz oscillator.
The following circuit uses a 455 khz ceramic resonator which gives good frequency.
Crystal oscillator vs resonator.
Just curious for input at this point i m not an egineer so i can t directly contribute to our community with such a pico sized hack.
I m enthused with your reference to the ceramic resonator bfo you described as well as by the other references in this forum but i m eager to see a pico sized bfo circuit that can accompany my shirt pocket sized grundig pe100.
It s not perfect but definitely helps tune the if coils in the elenco am kit.
