DS1054Z show amplitude in dBm with ref impedance? - Page 1
Forum section: electronics / testgear

author: bd139
author_rank: Super Contributor
timestamp: August 24, 2017, 10:31:03 am
content: Is it possible to get the DS1054Z to show amplitude in dBm? I'm terminating with a 50R feed through at the scope channel input.My DG1022Z allows output drive to be specified in dBm into a reference impedance of 50R. Was wondering if I could do the same with the scope at the other end. Would save me some legwork with the calculator!

author: bd139
author_rank: Super Contributor
timestamp: August 25, 2017, 04:48:10 pm
content: Done this the hard way.I wrote a simple-ish SCPI client in C# for the DG1054Z. This reads the Vpp reading from channel 1, does the relevant maths on it and displays it on a windows forms app once a second

author: MattSR
author_rank: Regular Contributor
timestamp: August 31, 2017, 08:32:43 am
content: Did you connect via USB or ethernet just out of interest?

author: bd139
author_rank: Super Contributor
timestamp: August 31, 2017, 09:47:37 am
content: Ethernet. USB doesn't really assume a "protocol" and requires drivers. The ethernet mode uses TCP/IP so you can just effectively telnet to the port and issue commands.

author: MattSR
author_rank: Regular Contributor
timestamp: September 02, 2017, 11:01:24 pm
content: I thought that might have been the answer. I see USB as being the "hard way" since it doesn't have a defined protocol like TCP/IP or GPIB for example.

author: Neganur
author_rank: Unknown
timestamp: September 03, 2017, 11:51:42 am
content: Does the rigol support advanced math functions?If so maybe you could just use a user defined functionI looked at the user manual but it wasn't clear to me if you could combine the functions or just use them individually:Math OperationDS1000Z can realize various math operations (including: addition (A+B), subtraction (A-B), multiplication (AxB), division (A/B), FFT, A&&B, A||B, A^B, !A, Intg, Diff, Sqrt, Lg, Ln, Exp and Abs. The results of math operation also allows further measurement (for details, please refer to “Cursor Measurement”).Press ? Math ? Operator in the vertical control area (VERTICAL) at the front panel to select the desired operator. The result of math operation will be displayed on the waveform marked with “M” on the screen after you press Display to enable the operation.

author: bd139
author_rank: Super Contributor
timestamp: September 03, 2017, 04:24:40 pm
content: I couldn't work the math functions out to be honest

author: abraxa
author_rank: Frequent Contributor
timestamp: September 03, 2017, 06:01:10 pm
content: Quote from: bd139 on August 25, 2017, 04:48:10 pmMind sharing? A quick search only showed calculators, tables and approximate values for sinusoidal waveforms.

author: bd139
author_rank: Super Contributor
timestamp: September 03, 2017, 06:28:57 pm
content: Off the top of my head, you'll have to fill in the gaps1. Convert reference power (1mW) into volts RMS in 50 ohm system: ref = sqrt(P*R)2. Convert sample voltage into RMS: sample = (vpp/2)*.7073. Divide one by the other ratio = sample/ref4. Take log of it: ratio = log(ratio)5. Multiply by 20: dBm = 20 * ratio.Disclaimer: haven't actually checked the above, just tapped it out quick. the program I have is tested but I don't ahve access to it at the current time.