ESC, Day Two on April One
In past years, ZigBee, BlueTooth and WiFi have been hot wireless topics here at ESC, and those radio standards are still around. But the big news this year in wireless seems to be the re-emergence of TRF (Tuned Radio Frequency). Both Atwater Kent and Philco are demonstrating TRF systems in their booths. Atwater Kent is just down the aisle from us (or up the aisle, depending on which way you are facing) in booth 262 and Philco is doing invitation only demonstrations in meeting room C8.
I haven't had time to stop at the Microchip (booth 416) or Atmel (booth 316) booths to see if they are developing software stacks for the AK or Philco TRF systems. If anybody has done so, feel free to pass me a note here.
Bluetooth is of course widely used in consumer devices and ZigBee is mostly used in custom embedded applications. TRF looks to be targeted more along the lines of applications that would have been ideal for WiFi or WiMax, such as broad-based information distribution. The TRF systems typically will not fit a star or point-to-point model, but more of a one-to-many or server to many client connectivity model.
One of the primary advantages of the TRF is in spectrum utilization. While most other standards are set to a very specific frequency and have bandwidth limitations to go with that specific target, the TRF will vary the bandwidth with the frequency. This allows for a greater number of receivers to be set in place and allows for multiple transmission stations to coexists with simple adjustment to the individual tuned frequency. Further, with a set of relatively easy to manage adjustments, receiving units can be converted to receive analog data from any of available transmitting stations within a reasonable range.
Unlike WiFi which has usable range of maybe a couple of hundred feet, in a field, going down hill with the wind at your back, or WiMax which can achieve city scale range with a large set of transmitters, TRF requires only a single transmitting station to reach receiving units for miles and miles. It is also a scalable system. Increasingthe power of the transmitting unit will increase the specific range. It is subject to the inverse square law like any other propagating signal, but through appropriate power devices, ranges in the dozens and even in some cases, the hundreds of miles can reliably be achieved.
If you have a chance, stop by the AK and Philco booths. Tell them Duane over a Screaming Circuits referred you. They're giving me a kick-back for everyone I send over.
Danger! 50,000 Ohms