Products > Test Equipment
Rohde & Schwarz ETL Broadcast Transmitter Analyzer
ocw:
I have been using a Rohde & Schwarz ETL broadcast transmitter analyzer lately and thought that I would provide pictures and displays from it. It can provide proof of performance measurements for both ATSC DTV and radio broadcast transmitters.
I will provide the DTV screens in this message. The radio ones will follow in another message. All the DTV measurements provided are from a station about 45 miles away from myself, so some readings are compromised by noise and propagation. All were taken via the automated measurement process.
The analyzer has worked well for me and provided me with a more enhanced capability of transmitter evaluation.
ocw:
Some of the radio parameter displays for the Rohde & Schwarz ETL broadcast transmitter analyzer are attached to this message.
It is amazing the number of measurements that this analyzer can make. While I should be providing transmitter site measurements from an RF sample, the attached readings are from a combination of my “mono” HP 8648C RF generator and a local stereo FM broadcast station about 15 miles from me. Like the DTV measurements, the radio ones were taken via the unit’s automated measurement process. The broadcast station did not have the needed test tones from the analyzer and the microphone level audio from the analyzer was too weak for my RF generator. So, I just fed the generator’s 1,000 Hz tone to provide modulation. That makes most of the audio measurements meaningless. My goal to provide examples of some of the measurements that it can make, not to provide a specific transmitter’s evaluation.
I corrected my HP8648C modulation problem and in my April 6th message below provide much better examples of the ETL's analysis of a FM signal.
Bicurico:
Ebay lists these devices as second hand at 20.000 Euro!
How much did you pay?
Is it for hobby/TEA or real (paid) work?
What are the spectrum analyser specs - especially max. span and frequency range?
Regards
Vitor
ocw:
--- Quote ---Ebay lists these devices as second hand at 20.000 Euro!
--- End quote ---
Few eBay listings have ETL's containing the radio analysis hardware that the unit which I am testing has. My employer purchased it new. I personally could only afford an EFA DTV analyzer (and other regular spectrum analyzers with better specifications).
The ETL includes a 3 GHz spectrum analyzer with tracking generator. Its span can be increased to that entire range. For complete specifications see:
https://scdn.rohde-schwarz.com/ur/pws/dl_downloads/dl_common_library/dl_brochures_and_datasheets/pdf_1/ETL_dat-sw_en_5213-7748-22_v2400.pdf
I measured the harmonics of a DTV transmitter at the upper extreme of the ETL's frequency range down to at least -145 dBc without much special effort other than an added high pass filter.
The ETL was ordered with the enhanced OCXO option, but not the GPS receiver. Attached are two screens showing it measuring the frequency of a GPSDO with an enhanced square wave output. Its harmonics at 990 and 2990 MHz were measured. It measured the 990 MHz harmonic 3.368 Hz low.
The ETL might be an enhanced FSL3 spectrum analyzer. Its value is more due to its broadcast DTV, radio, QAM, etc. measurement capabilities, not its basic spectrum analyzer features.
ocw:
Feeling a little embarrassed about the radio screens which I provided for the R&S ETL, I corrected the audio the audio problem to my HP 8648C RF generator and have a much better ETL FM signal analysis attached with this message.
While the 8648C cannot provide a stereo FM output, I left the ETL expecting a stereo signal along with RDS and SCA data. Not actually sending that, the ETL identified a lot of problems on the signal. The lack of stereo also provided poor cross talk figures.
But, look at some of the other data! Without any frequency correction on either, the ETL found the 8648C just 0.3 Hz off frequency. The frequency response, THD distortion and IMD were also excellent. Not a bad mono broadcast FM exciter.
Besides all that was provided, there are a variety of other modulation and modulation density screens available on the main and subcarrier modulation. Plus, it can combine the frequency response of a high pass filter with harmonic and spurious signal measurements to provide a single diagram with a higher dynamic range shown.
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