Rohde & Schwarz RTB2004

Update on 2023-03-25

I have sold this scope as I have purchased and have been using another one for some time. The main reason I have acquired another one is as follows and it might be helpful if you consider buying RTB series:

• RTB2004 does not have an 50 Ohm input.

• The maximum bandwidth of RTB2004 is 300MHz. This is a lot for some work, but not for some others.

New Oscilloscope

I have been wanting to buy a proper oscilloscope for some years for simple electronics work at home and finally I decided to buy one, Rohde & Schwarz RTB2004. I bought it as a bundle (RTB2K-COM4) so it includes all the options; 300 Mhz bandwidth, 4 analog channels, 16 logic channels, 2.5 GS/s sampling rate (this is when only channel 1 and 3 is in use, it is actually safer to say it is 1.25 GS/s), serial decoding (and triggering) (for I2C, SPI, etc.), history and segmented memory (160M), arbitrary waveform generator and frequency response analysis (bode plot).

I will probably update this post as I come across more things I like, or I do not.

I am not an oscilloscope power user and this is the most capable oscilloscope I have ever used, so take my words with a grain of salt. I am, naturally, not an employee of R&S, or I have any connection with R&S. I bought the oscilloscope myself, and this post is not funded by anyone.

The price of the bundle (RTB2K-COM4) is around 3.500 USD, but check with a supplier in your area since the price might be different.

My list of requirements

• It should be from a well-known vendor, like Tektronix, LeCroy, Keysight, R&S. It does not mean products from other manufacturers are not good but I just want to be on the safe side.
• I do not necessarily need 4 channels but I definitely need logic channels.
• I would like a high-end entry level model, because I do not want to hit a limitation before moving into higher models. As far as I understand the limit of basic/passive probes are usually around 300-500Mhz, so a minimum bandwidth of 200 Mhz.
• It is usually said that the sampling rate should be around 5x bandwidth, so for 200 Mhz, minimum 1 GS/s.
• Record length, sample memory or memory depth, The more the better basically.
• Waveform update rate. Like sample memory, the higher waveform/s the better.
• I am working with SPI, I2C etc., so decoding capability would be very nice or a must.
• Because I plan to use it to document measurements, it should be easy to take a screenshot.

Alternatives

After looking at all alternatives with similar feature sets from Tektronix (MSO2000B and 3 series MDO), Le Croy (T3DSO2000 and 3000 series), Keysight (2000 series) and R&S (RTB2000), I chose RTB2004 bundle. Here is why:

• 300 Mhz bandwidth is not common in this price range, usually alternatives are 200 Mhz. 350Mhz or 500Mhz alternatives are way more expensive, beyond my budget.
• 1.25 GS/s (and 2.5 GS/s if only two channels are used) is also one of the best in this price range, and it is reasonable for its bandwidth.
• It has a 10-bit ADC. This is quite unique to R&S at this price range. 10-bit ADC is normally found on higher models beyond my budget.
• It has a 10.1" display, which is also rare in this price range. It is a touch screen but I do not like using touch screen much (not because it is bad, I actually dont know because I dont use it), I use it with a wireless mouse.
• It has a USB port (both host and device) and an Ethernet port. USB host can be used for connecting USB memory sticks to store various things, USB device or Ethernet can be used to connect it to a computer. All these features are great for documentation and remote control. So there are three options for screenshot: USB memory stick, using its web server and livescreen there, using LXI (remote communication through Ethernet -maybe also through USB I dont use it-). I use livescreen or LXI, it is extremely easy to use. These features are sometimes available as options in alternatives (which adds to its base price) or available by default in higher models which are more expensive.
• It supports up to 50.000 waveform/s. I think this is the only place it is not better than others, Keysight has I think 200.000 wfm/s. I am not sure how different it is but I can say 50.000 wfm/s is very OK.
• It has 10M sample memory, and if you have history option (it comes with the bundle), it supports up to 160 Msample segmented memory. This is pretty amazing and again not very common in this price range.
• Since the bundle includes all the options, it comes with I2C, SPI, UART (and CAN and LIN) decoders, waveform generator and frequency response analysis (bode plot). If you do not get a bundle, all these options are pretty expensive both for R&S and for others.

Things I like

• Arbitrary waveform generator is very useful. I was not aware I would be using it this much. I do not have a separate function generator so it is the only one I use.
• Frequency response analysis (bode plot) is very nice.
• It can be used with a mouse.
• I was thinking I do not need 4 channels, but I actually used them pretty quick. Since you do not buy an oscilloscope everyday, I think it is a good investment to get 4 channels.
• The display is really nice. I am very happy I get this one because all alternatives at this price range has smaller screens.
• I think the user interface is very nice. I cannot compare it to alternatives since I did not use them but I am happy with this interface, it is pretty straightforward to use.
• It might be a small detail but you can adjust the brightness of the LEDs under the buttons. I usually work under dim light, so I am happy this is provided.
• It is so nice that it has an ethernet interface. The livescreen served by its embedded web server is pretty awesome. I also have not used LXI (remote communication protocol) before but it is extremely easy to use (lxi-tools package for Linux), I use LXI often to take screenshots.
• I think there is a fan inside but it is very silent, so a plus.

Update 29.11.2020, after 8 months of use:

• I still think same regarding to everything I mentioned above. I am quite happy with it.

Things I do not like

• Arbitrary waveform generator is somehow limited, its maximum frequency is 25 MHz for sine and 10 MHz for pulses. I wish it could do up to 50 MHz pulses at least.
• Frequency response analysis (bode plot) can only use analog channels, it cannot use the Math channels (e.g. bode plot ch1 vs. (ch2-ch3)). For example a simple IV curve of a diode can be done with an analog channel and with the difference between two channels (so without using a current probe or a differential probe), but this cannot be done because bode plot can use only analog channels. (yes you can plot IV curve in other ways but you got my point)

Update 29.11.2020, after 8 months of use:

• I wish it has 2 USB device ports (I did not try -I should- but I think it does not work with USB hubs). Because I always use it with a wireless mouse with a USB adapter, the port is always occupied. I do not need it usually, but if I need to use a USB memory stick, I need to unplug the mouse.
• I had an NRZ signal (like UART), but it had no idle time, so I think the serial UART decoder in that case is not working properly, it requires an idle time.

Things I neither like nor dislike

• It does not have individual position and scale knobs for channels. I think some people find this difficult to use, but I think it is OK. Of course it takes a bit more time to setup the channels etc, but I do not think it is an important limitation. It probably depends on your style of use or your use-case. I usually setup the things and they stay like that for a long time, so I do not care much if it can be done a bit more quickly.
• I am not sure if touch screen is a good idea, but you can use a mouse and it works great.
• Some people say the screen is too glossy. I actually put an anti-glare screen protector just after it arrived, so I cannot comment on that objectively but it is very easy to put an anti-glare protector if you are not happy with the glossiness.
• It has an annotation feature, which basically means you can write/draw over the signal screen. This is actually great but I am not sure if it makes sense or if it is easy to use. I have not tried yet but it might be nice if I can use this with an iPad.

Update 29.11.2020, after 8 months of use:

• Not something important, but each logic probe comes with 8 hooks, which is strange because it has 8 channels but there are also ground connections. So if you want to use many channels, you may need more hooks. I bought E-Z-Hook XKM.