# Phase noise of RFX900 daughter board **URL:** \ **Category:** GNU Radio\ **Created:** [February 10, 2014, 11:19pm UTC](https://www.ruby-forum.com/t/phase-noise-of-rfx900-daughter-board/239071 "2014-02-10T23:19:47Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Post date:** [February 10, 2014, 11:19pm UTC](https://www.ruby-forum.com/t/phase-noise-of-rfx900-daughter-board/239071/1 "2014-02-10T23:19:47Z")
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**Author:** ![Pengyu\_Z](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Pengyu\_Z](https://www.ruby-forum.com/u/Pengyu_Z)\ **Post date:** [February 10, 2014, 11:39pm UTC](https://www.ruby-forum.com/t/phase-noise-of-rfx900-daughter-board/239071/2 "2014-02-10T23:39:43Z")
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**Author:** ![Pengyu\_Z](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Pengyu\_Z](https://www.ruby-forum.com/u/Pengyu_Z)\ **Post date:** [February 10, 2014, 11:50pm UTC](https://www.ruby-forum.com/t/phase-noise-of-rfx900-daughter-board/239071/3 "2014-02-10T23:50:16Z")
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Pengyu, could you elaborate on your measurement procedure? What did you send on tx? 46dB attenuation does make sense in a output to input configuration, yet it is “only” about 30dB stronger than what I’d expect of crosstalk. Also: Did you use or bypass the SAW filters? What are the units on your graphs? An average amplitude of 3700 looks strange to me for such a measurement… also: scale! You’re using 250px for 1e6 samples, that’s 4000 samples per pixel, so if there was but a single sample that would have a high phase deviation, it would look the same as if all of the 4000 samples were phase jumping unceasingly. Anyway, your constellation diagram looks relevant, it shows the typical rotational widening of a constellation point that would appear in a communication receiver due to channel influences, inperfect synchronization and phase jitter. Maybe you should share the software you used to measure this, so that we can get a better understanding of what’s happening 🙂 Greetings, Marcus On 10.02.2014 23:18, Pengyu Z. wrote: > \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Discuss-gnuradio > mailing list [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - [http://www.enigmail.net/](http://www.enigmail.net/) iQEcBAEBAgAGBQJS+VdcAAoJEAFxB7BbsDrL6osIAIAteXbMWsiOXn5tcO4D8lq7 xfTy7sMGMhFIiE9cf41AerZZx/D0Nu7dSbDr0xkJsByLN0Xm0+KgGEr5gnGBP0XK 58dZWtsSpQJOo0dS63ko9Eiq7zegXOK5vrSKXYE919FfbM7qEiGL4lXG8WchIGLQ oZbw+0dyoNvLM+1nSleixPrZ9pxK0gTQvYHn6ig7abNaY8qynFeUUgXyk9ik+5fn SJ+CqIVPcAFOzmZSVquHtj7pqRZ33UIR4CvDP+b1ExrBYzaNfuE4l8WeWWjlpFA/ +1IpDDGBXyATyfoNgDPoiJkd/xdKNVuMKgswqDj6XwylQbsUU9P5mTSOysAQGos= =gtrn -----END PGP SIGNATURE----- ---
**Author:** ![Pengyu\_Z](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/e79b87/32.png) [@Pengyu\_Z](https://www.ruby-forum.com/u/Pengyu_Z)\ **Post date:** [February 11, 2014, 3:27pm UTC](https://www.ruby-forum.com/t/phase-noise-of-rfx900-daughter-board/239071/4 "2014-02-11T15:27:57Z")
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