Hi Dave and others - I played around with the CY22393. The quartz frequency is about 9MHz. The output was set to 108MHz. I don't have a SA, so looked on it with a ordinary fm radio. The modulation is a 800Hz tone made by controlling the output enable pin of the CY22393 with a microcontroller. It seems to have several spurs in the 100kHz to 5MHz range offset the 108MHz. I can hear the 800Hz modulation tone there several times. I know that modulating AM and detecting it with a fm type demodulator is not the best way. Unfortunately no RSSI display on the radio.
After thinking about what is going on, my question is: Is the 400ps spec in the datasheet another way of a spur definition? Can I simply see the jitter as a short-term time-delay at the output? This will translate the programmed nominal output frequency to another frequency... The CY22393 is a PLL-type system. One can set the PLL loop-bandwidth in a register. Unfortunately the data sheet doesn't cover this area, nor where optimum jitter performance would be possible. Maybe a good relation between quartz- and programmed output frequencies will drive jitter considerable down? Someone knows more? --- BTW: I have prototype SMD boards for most common SMD footprints to offer. Fits in ordinary 2.54mm pitch. So you can test a device like the CY22393 without making a dedicated pcb. regards - Henry drmail377 schrieb: > Forget using RS-232 as suggested in my post. I forgot to consider bits > per seconds vs bytes per second. RS-232 will never work for ADC/DAC, > sorry. David > > - In soft_radio@yahoogroups.com, "drmail377" <[EMAIL PROTECTED]> wrote: >> Sorry Dave, I missed the "Direct" conversion in your post. You mean >> direct A/D without QSD like Phil Covington's Quicksilver QS1R. That's >> a bit over my head at the moment. Right now I'm looking at a GPS >> stabilized DDS and bypassing the sound card using ADC/DAC's with a >> QSD. Direct method may be the next project. >> >> --- In soft_radio@yahoogroups.com, "drmail377" <drmail377@> wrote: >>> Hi Dave, >>> >>> Sorry for the late reply... Yes, I address the ADC/DAC from/to PC via >>> USB interfacing: >>> >>> http://groups.yahoo.com/group/soft_radio/message/3336 >>> >>> I'm just starting to look into the application software part of it >> though. >>> Thanks, David >>> >>> --- In soft_radio@yahoogroups.com, "Dave Wade" <g4ugm@> wrote: >>>> David, >>>> >>>> If you are a real purist why not sample at RF? I know the cost is >>> about 4x >>>> the cost of the Elektor kit but the result must be worth it. When I >>> looked >>>> at recent reviews in RadCom the direct sampling boards came out >>> realy well. >>>> Dave >>>> >>>> >>>> >>>> -----Original Message----- >>>> From: soft_radio@yahoogroups.com >> [mailto:[EMAIL PROTECTED] On >>>> Behalf Of drmail377 >>>> Sent: 03 April 2008 16:47 >>>> To: soft_radio@yahoogroups.com >>>> Subject: [soft_radio] Re: Elector Boards >>>> >>>> >>>> >>>> >>>> Hi Dave G4UGM, >>>> >>>> OK, this is top-down typing, please correct any obvious (and likely) >>>> glaring mistakes. I'm short on time... >>>> >>>> You raise excellent questions. You are right, theoretically the > divide >>>> by 4 for the quadrature LO will reduce phase noise by 20*log(4) > or 12 >>>> dB, but not really. Even at room temperature, and depending on the >>>> sequential quad-divide part thresholds, power supply noise, etc, we >>>> might want to at-least halve that. I'm looking into this further, >>>> especially considering the Silicon Labs Si570 20ppm LVDS part and >>>> Si571 voltage controlled ref input part (wrap the 571 around another >>>> PLL loop that is GPS disciplined perhaps?) >>>> >>>> Let's stick with 12 dB for now. I feel -135dBc/Hz at 10kHz is >>>> reasonable for a relatively high performance HF VFO. Let's work back >>>> from the example extrapolated from the Elektor's jitter to PN in my >>>> previous post assuming a -20 db difference from 1kHz to 10kHz, the >>>> center of interest for a 24 kHz BW. -135-12-20=-103 dBc/Hz at 1kHz, >>>> 18dB better than the extrapolated Elektor PN from the Cypress jitter >>> spec. >>>> Granted, there is a lot of "slop" in this analysis, but one might >>>> argue that an error margin of 20dB is not likely methinks. Also, the >>>> Cypress part may preform better at certain "select" frequencies and >>>> lower frequencies as well (Cypress doesn't disclose), yes it is > a PLL >>>> device, and as such can trade close-in vs. outer "hump" phase noise >>>> performance vs. loop BW. But we're interested in close-in > performance >>>> for HF reception. >>>> >>>> BTW my Peppermint "replacement" for the "Blueberry" now seemingly >>>> discontinued demo board for the device used in the Elektor LO is not >>>> performing anywhere near these numbers. A different animal entirely >>>> and seemingly no non EEPROM register to write to in order to set the >>>> frequency (EEPROM wear-out problem). >>>> >>>> But I am feeling better about the Elektor board after you raised > these >>>> questions Dave. Given that the Si570/671 from Silicon Labs wasn't >>>> available at the time the Elektor board was designed, the > Cypress part >>>> may have been the best choice. >>>> >>>> I'm sure the Elektor board is doing fine by most if not all users. >>>> However, I'm somewhat of a purist and the options for parts are >>>> changing rapidly. I just wish the Elektor board was more affordable. >>>> I'm a victim of the declining USD. >>>> >>>> 73''s David >>>> >>>> --- In [EMAIL PROTECTED] <mailto:soft_radio%40yahoogroups.com> >>> ups.com, >>>> "Dave Wade" <g4ugm@> wrote: >>>>> 1) Whats the phase jitter on a typical PC sound card? >>>>> >>>>> 2) Doesn't the divide by 4 reduce jitter. The chip is not used to >>>>> generate the IQ directly . >>>>> >>>>> 3) The ready built price to the UK is only marginally more >>>> than I can >>>>> buy the bits for. I can't find a ready built general coverage >> board in >>>>> Europe for anything like the price. >>>>> >>>>> >>>>> >>>>> -----Original Message----- >>>>> From: [EMAIL PROTECTED] <mailto:soft_radio%40yahoogroups.com> >>> ups.com >>>> [mailto:[EMAIL PROTECTED] <mailto:soft_radio%40yahoogroups.com> >>> ups.com] >>>> On >>>>> Behalf Of drmail377 >>>>> Sent: 28 March 2008 04:53 >>>>> To: [EMAIL PROTECTED] <mailto:soft_radio%40yahoogroups.com> >> ups.com >>>>> Subject: [soft_radio] Re: Elector Boards >>>>> >>>>> >>>>> >>>>> Hi Jack, >>>>> >>>>> You might want to rethink building that Elektor board, at > least the >>>>> way it is "out of the box". I took a good look at it and found >> that it >>>>> uses a Cypress Semiconductor CY27EE16 PLL Clock Generator as a >>>>> synthesized local oscillator. The CY27EE16 has a typical jitter >>>>> specification of 250ps rms. This is pretty bad. By comparison, a >> good >>>>> crystal oscillator should present less than 1ps rms jitter. To > give >>>>> you an idea how this translates to phase noise: >>>>> >>>>> 0.4psrms jitter (Isotemp OCXO134-10 10MHz VC-OCXO): >>>>> 10Hz = -105 dBc/Hz >>>>> 100Hz = -125 dBc/Hz >>>>> 1000Hz = -140 dBc/Hz >>>>> >>>>> 230psrms jitter (for comparison): >>>>> 10Hz = -50 dBc/Hz >>>>> 100Hz = -70 dBc/Hz >>>>> 1000Hz = -85 dBc/Hz >>>>> >>>>> Not only that, I get the feeling that the CY27EE16ZE may be > set for >>>>> deprecation. At least the Blueberry demo board for the part > has been >>>>> discontinued and replaced with a Peppermint demo board. The >> Peppermint >>>>> demo board uses a CY22393 three PLL clock synthesizer part. The >>>>> CY22393 has even worse specified jitter, a whopping 400psrms! But >>>>> there are allusions in the data sheet that the jitter may be >>>>> significantly less for some "settings", but it doesn't >> elaborate. I've >>>>> just received a couple of Peppermint boards to test. >>>>> >>>>> Anyway, the seemingly poor choice of L.O. on the Elektor radio, >> along >>>>> with the outrageously high price put me off. If you do build > one of >>>>> these, you might want to replace the CY27EE16ZE with an Si570. The >>>>> Si570's jitter is specified at around 0.35psrms. Mike, KF4BQ has >>>>> measured the phase noise of the CMOS version of Si570 to be >> -130dBc/Hz >>>>> at 3-7kHz offset. His report is in the Files section. >>>>> >>>>> If you do replace the CY27EE16ZE with an Si570 (or something > else), >>>>> remember the G8JCF SDR software that accompanies the Elektor radio >>>>> most likely will not be able to control the L.O. frequency. >> There's a >>>>> group here for the G8JCF software with some discussion on the >> Elektor >>>>> board as well - but not a lot of activity: >>>>> >>>>> http://groups. <http://groups. >>> <http://groups.yahoo.com/group/G8JCFSDR/> >>>> yahoo.com/group/G8JCFSDR/> >>>>> yahoo.com/group/G8JCFSDR/ >>>>> >>>>> 73's David (WB4ONA) >>>>> >>>>> --- In [EMAIL PROTECTED] <mailto:soft_radio%40yahoogroups.com> >>>> ups.com, >>>>> "artus1947" <artus@> wrote: >>>>>> Hi folks, >>>>>> >>>>>> I wonder if anyone knows of any other sources for the Elector >>>> Boards -- >>>>>> the shipping to the States (25 euros) is horrible. I tried > etching >>>> the >>>>>> boards myself, but I can't get a good registration between >> layers. >>>>>> Thanks. >>>>>> >>>>>> 73, >>>>>> Jack (W0FNQ) >>>>>> > > > > ------------------------------------ > > Yahoo! Groups Links > > > >
