http://www.dailymotion.com/video/x88a4w_spectrum_tech

δείτε το και … ακούστε το

επιτοπιε το ειδαμε το ακουσαμε αλλα το ρεζουμε ποιο ειναι δεν γνωριζουμε

Ριξτε και μια ματια σε αυτο….............Αντε Επιτοπιε...ξεκινα κατασκευη!!!

Materials and methods

It has often been cleared that an apparently innatural 28-KHz ultrasound frequency originates from the Sun Pyramid and Vratnica mound.
Ultrasounds can be briefly described as mechanical waves that we cannot hear even if they reach our ear because their frequency is higher than the maximum frequency detected by human beings. Actually because of its nature, the human ear can convey to the brain – which will then turn them into sounds – only acoustic waves having frequencies between 20 Hz and 20.000 Hz, even though not all individuals can detect these degrees. Therefore frequencies lower than 20 Hz and higher than 20.000 Hz cannot be detected by human beings as sounds, whereas many animals can hear frequencies lower than 20 Hz and others higher than 20.000 Hz (or 20 Kilo Hz).

However there are instruments suitable to detect frequencies overcoming our hearing abilities; on the Sun Pyramid actually such instruments recorded sounds with 28.000 Hz frequency.

Yet one thing is reading 28 KHz on a scale or on a display, another thing is listening or analysing that emission confirmed by the instrument.

To achieve this we benefitted from a project published by an Italian Journal, which is well known for the manufacturing of electronic kits not available on the market. The Journal’s name is Nuova Elettronica.

Issue 245 of 2010 published a project that could prove useful for our research, i.e an instrument able to "convert ultrasounds into audible sounds".

Instrument’s features

This project takes advantage of the ability of a particular microphone, which can be defined more correctly a supersonic sensor. Such sensor detects sounds whose frequency ranges between 10 and approximately 65 KHz.
Briefly one part of the instruments generates a variable frequency thanks to a knob and from that frequency the instruments withdraws the frequency received by the microphone. The result of such withdrawal can be heard into the headphones. For example, let us suppose that the microphone is detecting a 40 kHz-frequency (not audible); if, by rotating the tuning, we produce a 50-kHz frequency we will hear a difference between 50 and 40 kHz, i.e. a 10-KHz sound and it will be an audible frequency.

The signal coming from the sensor is then applied to an amplifier and the tension gain at this stage is approximately 100 times. In order to hear ultrasounds detected by a microphone, they need to be "conveyed" to a lower frequency, in order for them to be heard by a human being. The system we used is similar to that used in several radio receivers, in which the high frequency signal of dozens or hundreds MHz is lowered deeply compared to the incoming signal.

The instrument uses a variable beat-frequency oscillator and a two-entry mixer, used to produce an outgoing signal equal to the difference between the frequencies of the incoming signals, one generated by the instrument and the other coming from the microphone. The first frequency can be tuned with a tuner, as if looking for a radio station. The "different" signal is then cleared from possibile tension peaks and is conveyed to the second part of the intrument which amplifies it and conveys it to the headphones and/or to a recorder. The volume can be tuned.
To use the instrument, the parabola with the microphone must aim towards the direction to be examined, and by rotating the tuning potentiometer, ultrasound waves can be detected (if present), heard in the headphones or recorded if a tape or digital recorder is connected. This is just the beginning of the use of these instruments to ultrasound detected on the top of the Sun Pyramid. One can listen to the released sound, but at a lower tone, since the real sound is so high-pitched we could not imagine; the interesting feature to be searched is a possibile sound modulation. This is what we will try to do during the analyses of the different recordings.

σπυρο με αυτην την αναρτηση με εβγαλες απο μεγαλο κοπο ψαξιματος

Εχω και αλλα .Τι ακριβος ψαχνεις Παρη ?

τι έψαχνες Πάρη???? :36_1_47::36_1_47::36_1_47::36_1_47:

http://www.nuovaelettronica.it/prodotti/kit/strumenti-laboratorio/interfaccia-per-sismografo-1-1500

σας κανω τεστ εξυπναδας και μνημης :36_7_3:

Σπυρο ποιο ειναι το νουμερο του κιτ LX?

@toyo:

Ριξτε και μια ματια σε αυτο….............Αντε Επιτοπιε...ξεκινα κατασκευη!!!

μέσω Κροατίας : http://www.bosnian-pyramid.com/journal/2011/2/17/we-recorded-the-voice-of-the-sun-pyramid.html
αυτά αγαπητέ Σπύρο τα φτιάξαμε πριν 3-4 χρονάκια , άστο καλύτερα

Πάρη , αυτο που έβαλα καθαρά και μόνο Ακαδιμαικά για να δούν κάποιοι φίλοι πως ειναι το φάσμα των Συχνοτήτων , δεν νομίζω ότι χρειάζεται περαιτέρω ανάλυσις
φιλικά , epitopios