| ??? 06/21/06 00:03 Read: times |
#118663 - High pitched ring tones |
Listening to the various news reports I have learned that teachers are unable to cope with students that have the high pitched (17 kHz) ringtones downloaded to their cell phones. The idea is that older people cannot hear that frequency but the younger students can.
Would it be feasable to have a higher pitched device fill the room with, say, 19-20 kHz sound that no one can hear. Then, when a cell phone produces the 17 kHz tone would there not be a beat frequency (hetrodyne if my spelling is correct) of the difference? And would this frequency be audible? Maybe some enterprising young engineer could build a device the teacher could wear and provide the new tone via a tiny speaker near his/her ear. Once alerted that a cell phone is in use in class the teacher can then deal with the miscreant. |
| Topic | Author | Date |
| High pitched ring tones | 01/01/70 00:00 | |
| LM556 | 01/01/70 00:00 | |
| Download The Ring Tone. | 01/01/70 00:00 | |
| Adding signals with two frequencies | 01/01/70 00:00 | |
| Sure? | 01/01/70 00:00 | |
| Yes, quite sure. | 01/01/70 00:00 | |
| Intermodulation not beat frequencies | 01/01/70 00:00 | |
| Remember piano tuners | 01/01/70 00:00 | |
| A test should tell it | 01/01/70 00:00 | |
| Tuning instruments. | 01/01/70 00:00 | |
| Yes, but... | 01/01/70 00:00 | |
| Mixing 2 ultrasonic frequencys | 01/01/70 00:00 | |
| Cool! | 01/01/70 00:00 | |
| We experimented with the "ionovac" | 01/01/70 00:00 | |
Mixing two rf signals | 01/01/70 00:00 | |
| Adding signals with two frequencies | 01/01/70 00:00 | |
| Don't do that! | 01/01/70 00:00 | |
| I'm with Andy | 01/01/70 00:00 | |
| active noise reduction | 01/01/70 00:00 | |
| Rest your fears | 01/01/70 00:00 | |
| a better idea | 01/01/70 00:00 | |
| Detecting high pitch sounds | 01/01/70 00:00 | |
| No, no, do it the hard way | 01/01/70 00:00 |