Stanford Research SR780 vs HP 89440A - Page 1
Forum section: electronics / testgear

author: fourierpwn
author_rank: Regular Contributor
timestamp: March 07, 2017, 03:51:50 am
content: Hi all,I am trying to find out if these two units have similar capabilities. Intended use for (one of) them is low frequency noise measurements.SR780:http://www.thinksrs.com/products/SR780.htmHP/Agilent/Keysight 89440A:http://www.keysight.com/en/pd-89440A%3Aepsg%3Apro-pn-89440A/18-ghz-vector-signal-analyzer?pm=PL&nid=-536900197.536902189&cc=AU&lc=engWe have the SR780 currently being used for such applications, however I am trying to determine whether the HP 89440A would be better suited for the job but I am quite inexperienced in this field so I ask for some guidance.Thank you in advance.

author: technogeeky
author_rank: Frequent Contributor
timestamp: March 07, 2017, 04:08:21 am
content: It looks like the SR780 has higher real-time bandwidth:SRS780:102.4 kHz real time bandwidth per channel (2 channels by default)89440A:78.125 kHz real time bandwidth per channel (1 channel by default)This could be important depending on your application. Otherwise, all of the extra bandwidth the HP offers (up to 1800 MHz) is useless if you aren't looking at higher frequency signals. I'm a little confused by the specification of the HP, since it says the Frequency Range is 2 MHz to 1800 MHz, but then says Frequency Span is 1.0 Hz to 1798 MHz.The SR780 also has a whole slew of signal source that seem to be geared toward audio; the HP has a very generic looking source. The SR780 has a 2 megasample arbitrary source, while the HP has 8192 points.The SR780 seems to have better amplitude accuracy (+/- 0.2 dB compared to +/-1.6 dB full scale (+/- 0.5 dB typical)).I'm unsure how to compare RBW because of the way the SR780 is specified.

author: singapol
author_rank: Frequent Contributor
timestamp: March 07, 2017, 06:19:41 am
content: The SR780 is designed for low freq. noise/vibration measurements. It's got usb over SR760. Most important is that it has low noise signal generator for tests but do confirm first. HP does have similar models although it's no longer in it's inventory since rf is the rage now.

author: acbern
author_rank: Frequent Contributor
timestamp: March 08, 2017, 03:08:11 am
content: Why not the 35665? I use that for low frequency noise measurements, it also displays spectral density, and sometimes one can find them relatively cheap.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: March 08, 2017, 03:31:47 am
content: Resources for the 35665A:http://www.keysight.com/en/pd-1000001333%3Aepsg%3Apro-pn-35665A/dynamic-signal-analyzer-dc-to-1024-khz?cc=US&lc=enghttp://www.glkinst.com/test-equipment/

author: tecman
author_rank: Frequent Contributor
timestamp: March 11, 2017, 02:33:44 am
content: Completely different animals. The SRS is a low frequency (<100kHz), FFt analyzer. The HP is a HF analyzer. If your interest is LF, then the SRS is the better choice., UI have an Advantest R9211C for LF and Tek 2714 for HF. Each works best in in specified domains. So select one for the intended use.paul

author: rastro
author_rank: Frequent Contributor
timestamp: March 11, 2017, 09:11:47 pm
content: Have you considered HP 3563A which also has 2 channels and a signal source. The advantage of going HP is availability of schematics - not the case with SRS.

author: tecman
author_rank: Frequent Contributor
timestamp: March 12, 2017, 12:05:22 am
content: Quote from: rastro on March 11, 2017, 09:11:47 pm3562 also works, just does not have "digital" signal inputs. More available used.paul

author: rastro
author_rank: Frequent Contributor
timestamp: March 12, 2017, 02:25:21 pm
content: Yes the 3563 is a super set of the 3562.