On Sat, 8 Jun 2013 18:11:53 -0700, "garyr" <garyr@fidalgo.net> wrote:> >"Jim Thompson" <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in >message news:opv6r8hvktpml36sjh1d6ked2saa6f9clm@4ax.com... >> On Sat, 8 Jun 2013 11:09:36 -0700, "garyr" <garyr@fidalgo.net> wrote: >> >>>I want to make a simple rectifier for an RF signal, frequency less than 10 >>>MHz. The schematic below (view with fixed font) is from an article >>>describing a circuit useable with much higher frequencies and used a >>>hot-carrier diode (1N5711). For relative low frequencies would a general >>>purpose diode such as a 1N4148 be adequate? >>> >>>If a hot-carrier would be necessary I have a problem because I don't have >>>any but I do have a few high speed transistors: BSV52, BSF17, J310. Would >>>the base-emitter or base-collector junction of one of these transistors be >>>a >>>suitable substitute for a hot-carrier diode? >>> >>> | >>> \ >>> /R2 (20 uA bias current) >>> \ >>> C1 | R2 R3 >>> -||-+-/\/\-+-/\/\- >>> | | >>> v D1 = C2 >>> - | >>> | Gnd >>> Gnd >>> >>> >> >> Less than 10MHz, a 1N4148 should work just fine. >> >> A diff-pair configured as a unity-gain follower, but with just a >> long-time-constant R/C as the load makes a quite accurate >> rectifier/detector. (Some PECL gates are easily configured into this >> arrangement.) >> >> ...Jim Thompson[snip]> >I don't understand your diff-pair detector. Could you elaborate a bit? >As shown in... http://www.analog-innovations.com/SED/Peak-RF_Detector.pdf ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85140 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Hot-carrier diode substitute
Started by ●June 8, 2013
Reply by ●June 9, 20132013-06-09
Reply by ●June 9, 20132013-06-09
>> I don't understand your diff-pair detector. Could you elaborate a bit? >> > > As shown in... > > http://www.analog-innovations.com/SED/Peak-RF_Detector.pdf > > ...Jim Thompson >The first circuit is known as the junk buffer. I'm amazed that got past the patent office. It is basically the well known sat catcher circuit. You find them in LDOs. Then again, they are still patenting sat catchers, even with all the prior art. But nobody is going to court over them.
Reply by ●June 9, 20132013-06-09
"Jeff Liebermann" <jeffl@cruzio.com> wrote in message news:oo69r89c47i2p5vliajgu1u4nkob7c5hdf@4ax.com...> On Sat, 08 Jun 2013 20:22:46 -0700, Jeff Liebermann <jeffl@cruzio.com> > wrote: > >>This might be of interest: >><http://www.elecraft.com/Apps/RF_Det_application_note.htm> >>I have a roll of 1N270 (germanium) diodes if you want some. >>Send me a mailing address and I put some in an envelope. > > Some followup on the above article comparing 1N4148, 1N270, and > 1N5771: > <http://www.diystompboxes.com/smfforum/index.php?topic=90503.0;prev_next=next> > <http://www.cliftonlaboratories.com/diodes_for_rf_probes.htm> > For sensitivity and linearity, 1N270. > For high frequency sensitivity or broadband performance, 1N5771. > > -- > Jeff Liebermann jeffl@cruzio.com > 150 Felker St #D http://www.LearnByDestroying.com > Santa Cruz CA 95060 http://802.11junk.com > Skype: JeffLiebermann AE6KS 831-336-2558Thanks for the information and the offer. My application is not critical so almost any diode would probably be OK.
