External reference from ICS512 (PLL CLOCK MULTIPLIER)


  • Hi Detlev,

    I could not do any sensible measurements at 40MHz because my hybrid couplers are not good enough at that frequency.

    So I used a different approach and made a measurement at 50MHz.

    The picture shows the 50MHz (+8dBm) carrier passing through a 50.125MHz crystal filter, the filter attenuates the 50MHz signal by almost 50dB.

    What is left is the true RMS level of noise passing through the filter, The cursor shows the analyser noise floor at -122.5 dBm.

    The Leo Bodnar device noise measured at 50.100MHz is -107dBm.

    As to how that will relate to 40MHz I will leave to others. This is my final opinion on the subject.

    Regards everybody and stay safe.

    Ron.

  • in any case issue with ISC5XX series i was test in 2014. for simple explane final PHASE NOISE value will lower than -40dBc/Hz at 10 kHz offset. from datasheet page of IDT_511 device: One Sigma Clock Period Jitter tjs 25 ps. (This parameter of ICS512 is 70 ps!!!) see datasheet pages of devices

    https://rf-tools.com/jitter/- calculator link


    LTC6950 is better solution, is 1.4GHz Low Phase Noise,Low Jitter PLL with Clock Distribution device

    https://www.analog.com/media/en/technical-documentation/data-sheets/6950f.pdf

  • Hello all, I have access to an R&S FSUP and can measure PN . I have attached a few examples in the pdf, You can pretty much infer results for other frequencies for the Leo Bodnar results from the 10 MHz plot included. If you want to see 40MHz and 25MHz specifically I should be able to measure them on Friday this week.


    PN measurements-PA5Y.pdf


    Regards


    Conrad PA5Y

  • The ICS512 and similar devices have never been great performers in regards of phase noise. To my knowledge, these ICS-chips are also no longer manufactured. Renesas offers much better clock generators / jitter attenuators, like the 5P49V6975 or RC22504A. I actually just ordered a bunch of both devices a few weeks ago. Since they have multiple, independent outputs, I'd like to experiment with a versatile 10 MHz to some other frequencies translator prototype. It might be possible to use these devices to generate all the different frequencies one might need for a QO-100 set-up with just one device.

  • The ICS512 and similar devices have never been great performers in regards of phase noise. To my knowledge, these ICS-chips are also no longer manufactured. Renesas offers much better clock generators / jitter attenuators, like the 5P49V6975 or RC22504A. I actually just ordered a bunch of both devices a few weeks ago. Since they have multiple, independent outputs, I'd like to experiment with a versatile 10 MHz to some other frequencies translator prototype. It might be possible to use these devices to generate all the different frequencies one might need for a QO-100 set-up with just one device.

    Great!


    PY1SAN

    GG77sn

    Rio de Janeiro

  • Hi


    I use a duplicator (x2.5) on NB3N3020.

    In TRV on QO-100, there is no difference in reception using the VCOCXO 25MHz clock.

    The phase noise of the NB3N3020 chip is, respectively:

    100Hz from the carrier -95dBc/Hz;

    1kHz -107dBc/Hz;

    10kHz -112dBc/Hz;

    100kHz -117dBc/Hz;

    1MHz -117dBc/Hz;

    10MHz -134dBc/Hz;

    for an output frequency of 125MHz and multiplication of 5 times.


    These are really very good parameters and predispose the chip for use in radio receivers, even high-end ones. The NB3N3020 chip includes a phase loop and a number of frequency dividers. The tuning range of the oscillator is from 8 to 210 MHz, and the input frequency can be duplicated from 1 to 16 times. Other multiplication multiples (e.g., being fractional values) are obtained by duplicating the reference frequency and then dividing it. The circuit is programmed by changing the state of the Sel0, Sel1 and Sel2 control inputs with three states: LOW, i.e. by shorting the corresponding pin to ground, HIGH by applying a high state to the input (+3.3V), and MID by leaving the input unconnected - the logic state is then determined by the circuit's internal resistors

    Photo:


    73

    Artur

  • I finally found the time to play around with the 5P49V6965 devices. They function as they're supposed to and happily translate frequencies. They accept a pretty broad range of input voltage levels way beyond the manufacturer's specifications. Therefore, I'll go ahead and design a little board that'll translate a 10 or 25 MHz reference signal to 4 other frequencies. It is possible to include an on-board TCXO and allow a switch-over to an external reference as the device has two different input clock pins.


    If restricted to 4 fixed output frequencies, what would your opinions be on what the 4 most useful output frequencies would be?


    On my initial design I would just use the 5P49V6965 as a stand-alone device, so the output clock properties will have to be burned statically into the device. If we can determine the 4 most useful frequencies, I can implement them so that other members of this forum can test the prototype boards as well. Later on I can include an MCU, or USB programming port, to make the board more versatile. Looking forward to your input on this one.


    Here's a quick write-up on my blog about the (few) experiments I have conducted so far: https://baltic-lab.com/2023/07…as-versaclock-6e-devices/

  • Hi


    The topic is interesting so I tried a practical experiment: NB3N3020 vs ICS512.

    1) The measurement circuit looked like this photo: 0.jpg.

    2) TRV is without a case is powered by OCXO 10MHz photo: 1.jpg.

    3) OCXO 10MHz x2.5 through NB3N3020 chip to LNB. Bicon QO-100 received at: 81dBm. Photo: 2.jpg

    4) TRV board with NB3N3020 chip installed. Photo: 3.jpg

    5) Installed adapter (prosthesis) NB3N3020 on ICS512. Photo: 4.jpg

    6) Installed ICS512. Photo: 5.jpg

    7) Checking that ICS512 works well (multiplies x2.5) Photo: 6.jpg

    8 ) TRV does not receive the bicon after installing ICS512. Noise: 90dBm. Photo: 7.jpg

    9) Avers TRV. Photo:8.jpg


    The conclusion is that ICS512 is not suitable for X2.5 for LNB to QO-100

    Thank you for your attention.


    73

    Artur

  • Hi Artur,
    Happy new year. I am planning to replace the 2x hackRF One boards I used for qo-100 NB with an adalm Pluto I got (Enclosure says Rev C, PCB inside says Rev D).

    Apart from the GPSDO solution (I am not planning to buy a Leo Bodnar GPSDO at this point and already have one DIY GPSDO with 10MHz OCXO) what is the best and easy solution for NB operation?

    10MHz OCXO >> NB3N3020 (in x4)?

    ** I have searched the forums for few days, and apparently couldn't find the exact information.

    Please suggest.
    Fazlay/S21RC