Search found 4 matches
- Tue May 16, 2006 10:56 am
- Forum: General Discussion
- Topic: People detecting
- Replies: 7
- Views: 4309
Backin the 70's I designed some ultrasonic motion detectors for the security industry. They are probably still the most reliable way of detecting people- particularly as you can (if you want) readily remove the effects of things like curtains blowing and pets running around. The 40kHz sensors used b...
- Tue May 16, 2006 10:51 am
- Forum: General Discussion
- Topic: ID this RFID
- Replies: 10
- Views: 4535
- Tue May 16, 2006 10:49 am
- Forum: General Discussion
- Topic: What kind of wire?
- Replies: 7
- Views: 3513
- Tue May 16, 2006 8:12 am
- Forum: General Discussion
- Topic: The dBu re-examined...
- Replies: 12
- Views: 4844
Well, the dBu, like the dBm, dBV and so on are all defined in ANSI T1.523-2001. The dBm is a power ratio referred to 1mW in 600 ohms, for audio, or in 50 ohms usually for RF, dBu and dBV are voltage ratios. The dBu is grandfathered in on the basis that 0.775V RMS is the standard reference voltage fo...