Paul Keinanen wrote:> On Mon, 29 Oct 2007 09:04:19 -0700, Joerg > <notthisjoergsch@removethispacbell.net> wrote: > >> Paul Keinanen wrote: >>> On Sun, 28 Oct 2007 15:24:31 GMT, Joerg >>> <notthisjoergsch@removethispacbell.net> wrote: >>> >>>> Paul Keinanen wrote: >>>>> On Wed, 24 Oct 2007 13:34:29 -0700, Joerg >>>>> <notthisjoergsch@removethispacbell.net> wrote: >>>>> * data rate needed, both up- and downlink (and hence bandwidth and >>>>> regulatory limits) >>>> Very low, basically no more than a TV remote has to communicate. 300bps >>>> would be plenty. >>> That significantly increases the range. However, the frequency >>> accuracy and temperature stability requirements can become quite >>> demanding and it would be questionable, if a built in crystal >>> oscillator would be stable enough. >>> >> On higher frequencies all you can really do is sweep and then AFC-lock. >> Else it becomes prohibitively expensive. > > This is a good system for full-duplex links in areas with low > interference. For instance various "Gunnplexer" systems consisting of > one more or less stable Gunn diode master station at 10 GHz sends out > a constant carrier and the slave station uses frequency locking to > lock into that signal and then generates the uplink 100 or 144 MHz > above or below the downlink. > > However, with half duplex communication, you would have to send a very > long preamble before the message to allow locking to the incomming > signal. If the data rate is below 300 bits/s, which would require > about 300 Hz bandwidth with BPSK, you would need less than 1 ppm > accuracy at 433 MHz, which would be quite expensive. With 10 ppm > accuracy, you definitively would need to scan the 4.3 kHz bandwidth > for the signal. This is OK, as long as the desired signal is the only > signal within that bandwidth. > > If many similar signals are within that band, you would have to check > for correct code, before proceeding into next carrier. As long as the > actual message is quite long, you could tolerate a long > synchronisation preamble. > >>> Those frequency bands as well as 2.45 GHz are known as ISM >>> (Industrial, Scientific, Medical) bands and they were _not_ intended >>> for radio communication but for e.g. RF-heating of the human body, >>> food and plastics (welding). >>> >>> Later on, various license free radio communication applications were >>> allowed on this "wasteland" of spectrum and the communication systems >>> had to cope with the ISM usage e.g. by using spread spectrum to avoid >>> the interference from ISM devices. >>> >>> If you need some degree of protection for your communication system, >>> you should use a licensed frequency band. >>> >> That is very much impossible for consumer gear. I remember when we got >> our first microwave, pretty much the first people in town, and the radio >> authority folks in Germany had to come out and bless the "installation". >> That was a substantial roadblock and later removed. > > Was that on the former 1.27 GHz ISM band or at 2.45 GHz ? >AFAIR it was on 2.45GHz. But in the 70's that was not released for public use in Germany so each unit needed a license. Pretty impressive when one of those yellow vans with lots of rotating antennas stops at your house and neighbors become curious what happened. -- Regards, Joerg http://www.analogconsultants.com/
Micro controllers with UHF transceivers?
Started by ●October 24, 2007
Reply by ●October 29, 20072007-10-29
Reply by ●October 30, 20072007-10-30
Joerg wrote:> Hello Folks, > > After some Google searching and perusing the sites of the usual > contenders I only found one uC family that has serious on-chip RF > transceiver capabilities, the Cypress CYWUSB6953 and its brethren. > rfPICs and others usually only have a transmitter. > > Anyhow, the Cypress will only serve 2.45GHz but I need the lower UHF > bands for range reasons. Is anything coming down the pike soon or will > that have to remain a two-chip solution? >You've seen the new device from TI ? Sub GHz and adds USB ? Part name Frequency Flash RAM USB CC1110 Sub-1 GHz 8/16/32 KB 1/2/4 KB No CC1111 Sub-1 GHz 8/16/32 KB 1/2/4 KB Yes CC2510 2.4 GHz 8/16/32 KB 1/2/4 KB No CC2511 2.4 GHz 8/16/32 KB 1/2/4 KB Yes http://www10.edacafe.com/nbc/articles/view_article.php?section=ICNews&articleid=452233
Reply by ●October 30, 20072007-10-30
Jim Granville wrote:> Joerg wrote: >> Hello Folks, >> >> After some Google searching and perusing the sites of the usual >> contenders I only found one uC family that has serious on-chip RF >> transceiver capabilities, the Cypress CYWUSB6953 and its brethren. >> rfPICs and others usually only have a transmitter. >> >> Anyhow, the Cypress will only serve 2.45GHz but I need the lower UHF >> bands for range reasons. Is anything coming down the pike soon or will >> that have to remain a two-chip solution? >> > > You've seen the new device from TI ? > Sub GHz and adds USB ? > Part name Frequency Flash RAM USB > CC1110 Sub-1 GHz 8/16/32 KB 1/2/4 KB No > CC1111 Sub-1 GHz 8/16/32 KB 1/2/4 KB Yes > CC2510 2.4 GHz 8/16/32 KB 1/2/4 KB No > CC2511 2.4 GHz 8/16/32 KB 1/2/4 KB Yes > > http://www10.edacafe.com/nbc/articles/view_article.php?section=ICNews&articleid=452233 >Yes, those are already on my list. There are a bit above the Dollar pain threshold right now and some clients frown upon the 8051 architecture (not me, I actually like it). -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●October 30, 20072007-10-30
"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message news:qgIVi.9684$Pv2.9474@newssvr23.news.prodigy.net...> Yes, those are already on my list. There are a bit above the Dollar pain > threshold right now and some clients frown upon the 8051 architecture (not > me, I actually like it).Hopefully they realize that one of the reasons the 8051 architecture is still so popular is because it's dirt cheap!
Reply by ●October 30, 20072007-10-30
Joel Koltner wrote:> "Joerg" <notthisjoergsch@removethispacbell.net> wrote in message > news:qgIVi.9684$Pv2.9474@newssvr23.news.prodigy.net... >> Yes, those are already on my list. There are a bit above the Dollar pain >> threshold right now and some clients frown upon the 8051 architecture (not >> me, I actually like it). > > Hopefully they realize that one of the reasons the 8051 architecture is still > so popular is because it's dirt cheap! >Sure is. Also, you can find local programmers in even the smallest of towns which is a huge upside. Last but not least there is often a 2nd source. If there ain't you can usually find a very similar 8051 device so that code portability isn't a serious issue. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●October 30, 20072007-10-30
On Tue, 30 Oct 2007 17:28:28 GMT, Joerg <notthisjoergsch@removethispacbell.net> wrote:>Joel Koltner wrote: >> "Joerg" <notthisjoergsch@removethispacbell.net> wrote in message >> news:qgIVi.9684$Pv2.9474@newssvr23.news.prodigy.net... >>> Yes, those are already on my list. There are a bit above the Dollar pain >>> threshold right now and some clients frown upon the 8051 architecture (not >>> me, I actually like it). >> >> Hopefully they realize that one of the reasons the 8051 architecture is still >> so popular is because it's dirt cheap! >> > >Sure is. Also, you can find local programmers in even the smallest of >towns which is a huge upside. Last but not least there is often a 2nd >source. If there ain't you can usually find a very similar 8051 device >so that code portability isn't a serious issue.I like the architecture as well, for very small applications only, of course. They took the Mark I MCS-48 series and added all the stuff that was missing. Most of the modern variants dispense with the horrible pseudo-bidirectional ports and add useful peripherals that were missing or were very primitive in the earlier versions. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Reply by ●October 31, 20072007-10-31
Joel Koltner JKolstad71HatesSpam@yahoo.com posted to sci.electronics.design:> "Joerg" <notthisjoergsch@removethispacbell.net> wrote in message > news:qgIVi.9684$Pv2.9474@newssvr23.news.prodigy.net... >> Yes, those are already on my list. There are a bit above the Dollar >> pain threshold right now and some clients frown upon the 8051 >> architecture (not me, I actually like it). > > Hopefully they realize that one of the reasons the 8051 architecture > is still so popular is because it's dirt cheap!Don't forget the second part of dirt cheap, there is plenty of expertise out there running around. Can you say self-fulfilling prophecy?
Reply by ●October 31, 20072007-10-31
"JosephKK" <joseph_barrett@sbcglobal.net> wrote in message news:Si_Vi.3669$Nz7.3392@nlpi070.nbdc.sbc.com...> Don't forget the second part of dirt cheap, there is plenty of > expertise out there running around. Can you say self-fulfilling > prophecy?Yep... PICs are the same way -- not the world's most inspired architecture, but dirt cheap and made readily avaialble to hobbyists/college students/etc. early one; now they're a everywhere too.
Reply by ●October 31, 20072007-10-31
JosephKK wrote:> Joel Koltner JKolstad71HatesSpam@yahoo.com posted to > sci.electronics.design: > >> "Joerg" <notthisjoergsch@removethispacbell.net> wrote in message >> news:qgIVi.9684$Pv2.9474@newssvr23.news.prodigy.net... >>> Yes, those are already on my list. There are a bit above the Dollar >>> pain threshold right now and some clients frown upon the 8051 >>> architecture (not me, I actually like it). >> Hopefully they realize that one of the reasons the 8051 architecture >> is still so popular is because it's dirt cheap! > > Don't forget the second part of dirt cheap, there is plenty of > expertise out there running around. Can you say self-fulfilling > prophecy? >Exactamente. While an MSP430 programmer might have to be flown in you can usually find 8051 guys right there. -- Regards, Joerg http://www.analogconsultants.com/
