Скачать с ютуб Audio speech filter gives less noise when receiving radio stations on Shortwave (demo and schematic) в хорошем качестве

Audio speech filter gives less noise when receiving radio stations on Shortwave (demo and schematic)

Please read the description first, also the final lines where I give links to earlier video's about this subject, where I started with that LM 386 Chip. Set the resolution when looking via YouTube at the video to full HD = 1080, to see the schematic. When you want to the practical results of this audio filter when receiving on Shortwave ( 7 october 2024), it is here    • Receiving Radio stations in the 12 MC...   I show, now, an audio amp for say 1.5 Watt in combination with a ”speech” audio filter. To be connected to the headphone output of a computer, when it receives (via SDR = Software Defined Radio) a certain radio station on Shortwave. Of course this audio filter (FET + NPN transistor) is also usable for other audio applications, not related to SDR Radio (!). Aim (and realized): maximal intelligibility, lowest noise (as possible) when receiving radio stations on Shortwave via that headphone output of a computer. Can also be the headphone output of a MP3 player, the headphone output of a Smartphone, etc. Its output impedance is (their output impedances of these devices are) low and its (their) output level(s) is/are high, say in the 100-200 MilliWatt range, that is why I made this circuit in the way that I show it here. Reason of using that 22 Ohm resistor. Can also be 27 Ohm. This circuit can also be used for many other purposes, where a sharp “audio band” filter is necessary. Thus pressing the noise (everything above 8 KC) down + pressing the lowest frequencies of the audio range (say 2000 Hz or lower) down to a very low level, so that speech is better intelligable. This schematic does that job, the demo shows its properties. The showed end amplifier (with the 2 X BD types) with this filter unit works between 9 Volt and 12 Volt. It is completely classical, I published it more than once on my YT Channel. Relevant: you see in the schematic that I have connected the (-) of headphone computer out in the schematic in a certain way. I made a question mark (?) there. Can the minus (-) of the audio amp. be connected directly to the (-) (=minus) of the computer board? Sometimes that will/cannot work, because of “earth loops”. In that case you must connect the (-) of the headphone output of the computer via a non-polar capacitor in the order of 0.47 uF (=470N) to the mass (minus) of this filter/amplifier board. I did not do that here/now (I directly connected the minus of the computer board, its headphone out, to the minus of the audio amplifier circuit) & I cannot give a precise solution. It depends on the computer board that you use. The way it receives its voltages/current via its power supply to the “mains”, be it 230 V/50 Hz or 110 V/60 Hz. Minus (-) and mass (ground) do not always work together. This is a disclaimer, that is why that 470 N - 230 Volt separation capacitor can be used for safety purposes (visible in the schematic). Furthermore: Everything is told in this video. It works nice, pressing ennoying noise down and lifting up the speech range of a radio signal. Plus many properties to align that good intelligibility to your own needs, via the 2 potentiometers and that switch (low/high audio). My You Tube channel trailer (Radiofun232 on YouTube) is here    • Radiofun232 on YouTube (updated monthly)   YouTube/Google hinders me by not making a direct link to my channel trailer. That problem started in 2020/2021. The hinder started during the "Covid" discussion on the www. It is a form of shadow banning because I am very critical about mass injections of people, all over the world, against Covid, since (say) 2020. So I have to do a separate action when I want to give my YouTube Channel link in the textboxes of the video's that I upload. YouTube/Google does not want to give a direct link to my critical remarks, visible on my YT Channel trailer. When you search, search always “NEWEST FIRST” to get the right overview. You can also search via the “looking glass” on my Channel trailer via keywords like ”audio”, “radio”, “amplifier”, “filter”, etc. My books about electronics & analog radio technology are available via the website of "LULU”, search for author “Ko Tilman” there. https://www.lulu.com/search?adult_aud... I keep all my YT videos constant actual, so the original video’s with the most recent information are always on YouTube. Search there, and avoid my circuits that are republished, re-arranged, re-edited on other websites, giving not probable re-wiring, etc. Some persons try to find gold via my circuits. I take distance from all these fake claims. I cannot help that these things happen. Upload 4 October 2024. First video where another Chip, the LM 386, was tested/used (29 Sept 2024) in this application:    • LM 386 used as 0,5 Watt audio loudspe...   And more considerations about that LM 386 Chip (in fact a too low output level for this purpose, in combination with a filter) 30 Sept 2024    • LM 386 as audio amp. 0,5 Watt, connec...