Review The Rigol DS1052E and Tektronix TBS1042 Oscilloscopes

Review The Rigol Ds1052e And Tektronix Tbs1042 Oscilloscopes-Free PDF

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Vertical Resolution 8 bits 8 bits, Max Input Voltage rms 300V 30KHz 60V 50MHz 300V 100KHz 13Vpk 3MHz and above. Probe Impedance 1 1 1M 100pf 10 110M 17pf 10 1 only 10M 20pf. Math x FFT x FFT,Std Interface USB front rear RS232 USB front rear. Size Weight 12 W x 6 H x 5 1 2 D 5 1 lbs 13 W x 6 H x 5 D 4 9lbs. Let s make a few tests, Both of these oscilloscopes are very easy to use and have similar specifications So I selected. some tests that I thought many hams would find useful and interesting. For the first test I looked at the measured frequency response of the oscilloscopes I measured. RF power with the calibrated set up of Figure 1 and checked the amplitude of the frequency on. 7 28 and 50 MHz As the Rigol has a 50MHz bandwidth and the Tektronix has a 40MHz. bandwidth I would expect to see some roll off on 10 and 6 meters This doesn t mean you. can t look at signals just that the amplitude of higher frequency signals may not be completely. Oscilloscope,IC 706MKIIG 40dB Attenuator MiniCircuits PWR 6GHS. 10W Output Calibrated Power Sensor,Figure 1 Frequency Response Test Set Up.
My next test involved measuring transmitter overshoot as shown in Figure 2 When a. transceiver s output power is reduced often the transceiver output will overshoot the set power. on the first dit or speech syllable as a finite time is required for the transceiver s ALC to. control the signal If this overshoot is high enough it can trip off an external amplifier or even. damage it For this test I set my IC 706MKIIG to 25 watts output as this is the approximate. drive power needed for full output from my KPA500 amplifier. Oscilloscope,IC 706MKIIG Channel 1 40dB Attenuator PWR 6GHS. 25W Output Calibrated Power Sensor,Figure 2 Transmitter Overshoot Test Set Up. Next I wanted to look at the amplifier enable disable timing versus the RF signal output This. timing is important when driving an amplifier so as to ensure that no hot switching of the. amplifier or transceiver takes place And both the amp key to RF signal and RF signal to amp. unkey timings are important as you want to make sure that there is no chance of hot switching. on either amplifier keying or amplifier unkeying As shown in Figure 3 I fed the IC 706MKIIG. HSEND output to channel 2 on the oscilloscope and set the oscilloscope to trigger on channel 2. A falling edge trigger shows the amp enable timing and a rising edge trigger shows the amp. disable timing I could have fed HSEND into the EXTERNAL TRIGGER input on the. oscilloscope but I wanted to display HSEND along with the RF signal to better clarify the. Oscilloscope,Amp Key Out Channel 2,IC 706MKIIG Channel 1 40dB Attenuator PWR 6GHS. 25W Output Calibrated Power Sensor,Figure 3 Amp Enable Disable Test Set Up. My final test involved 2 tone testing of my transceiver A 2 tone test is a standard test of your. transceiver s linearity that normally requires a spectrum analyzer However both oscilloscopes. have a fast fourier transform FFT math feature which should permit you to display the signal in. the frequency domain For this test a 2 tone audio signal is fed into the transceiver s. microphone input and the composite level adjusted for 25 watts peak output power After. displaying the normal modulated RF signal on the oscilloscope select FFT and make sure you. are displaying in the dB scale Now use the vertical know to select dB division the horizontal. timing knob to select the Hz division and center up the signal on your display with the. horizontal position control Figure 4 shows my set up. Oscilloscope,IC 706MKIIG Channel 1 40dB 20dB Rigol DSA815 TG.
25W Output 60dB Attenuator Spectrum Analyzer,Calibrated. PreciseRF TTG1 Figure 4 2 Tone Test Set Up,2 Tone Generator. The Tektronix TBS1042, Like many computers and test instruments today only a condensed version of the manual was. enclosed with the TBS1042 The full manual 159 pages is downloadable on line The only. accessories provided with the oscilloscope are the 120VAC power cord and a pair of 10 1. oscilloscope 10 1 probes not switchable to 1 1 However for most measurements you ll want to. use a 10 1 probe as the capacitive loading of a 1 1 probe will be a problem for higher frequency. RF signals plus a 10 1 probe provides better overload protection should you accidentally. connect to a high voltage source A 1 1 probe is most usable only for audio measurements at. very low signal levels, An important feature of any instrument is its ease of use Therefore I attempted to use the. TBS1042 without reading the manual other than reading how to compensate the probes As it. turned out I was able to quickly set up and measure everything in all the tests without cracking. the book What makes this easy is the AUTOSET button that sets up the unit for you Just apply. a signal and press AUTOSET Within a few seconds you ll have a display that will be very close. to what you want From this point you can simply change the vertical sensitivity and horizontal. timing to refine the display to your liking The USB port on the front of the unit provides either. print or save functions The TBS1042 determines if the connected device is a printer or memory. stick and will either print or save the screen data when the PRINT button is pushed. The frequency response test resulted in a measured roll off of 0 57dB on 10 meters and 1 67dB. on 6 meters much better than the 40MHz 3dB specification. For the overshoot test I set my transceiver output to a nominal 25 watt level and triggered the. TBS1042 on the channel 1 input You have a choice of enabling either two horizontal cursors to. measure amplitude or two vertical cursors to measure time I enabled the horizontal cursors to. display the overshoot amplitude The results are shown in Figure 5 Note that with a set output. power of 25 watts the output peaks at 72Vpk 100 watts on the first dit. Figure 5 IC 706MKIIG Overshoot Measurement, Next I looked at the amp key enable Figure 6 timing with the IC 706MKIIG set for full break.
in The blue trace is the amp enable HSEND line out of the IC 706MKIIG The results are. interesting The amp enable to RF output time of 15 milliseconds is fine for vacuum relays and. PIN diodes It is probably OK for open frame relays used on many non QSK amps but it is. marginal I e a typical enable time for open frame relays is typically 12 20 ms. Figure 6 IC 706MKIIG Amp key to RF output timing, The amp disable timing Figure 7 shows a problem with QSK switched amplifiers I e the. amp disable line goes high about 4 milliseconds BEFORE RF drops to zero the vertical cursors. were enabled to better show this So you may hot switch a QSK amplifier if operating full. break in To be on the safe side IC 706MKIIG users should only operate semi break in. Figure 7 IC 706MKIIG RF amp disable timing, My last test was a 2 tone test of the IC 706MKIIG Figures 8 and 9 compare the displays of a. real spectrum analyzer a Rigol DSA815 TG with the FFT display on the TBS1042 As you can. see the TBS1042 frequency display is virtually identical to the spectrum analyzer. Figure 8 Spectrum analyzer display of IC 706MKIIG 2 tone test. Figure 9 TBS1042 2 tone test FFT display,The Rigol DS1052E. There was not an abbreviated manual supplied with the DS1052E However the full manual. 166 pages is downloadable on line The DS1052E includes a 120VAC line cord a pair of. switchable 10 1 1 1 oscilloscope probes and a USB A B cable for interfacing to your computer. Again I attempted to use the oscilloscope without reading the manual other than the probe. compensation And again I had no problems The AUTO button on the Rigol oscilloscope is. equivalent to the AUTOSET button on the Tektronix oscilloscope After applying a signal press. AUTO and then adjust the vertical sensitivity and horizontal timing to refine the display to your. The ONLY thing I had problems with was saving the display to a USB memory stick The. SAVE procedure is very flexible permitting you to save different formats and even permitting. you to name the files The SAVE process wasn t intuitive requiring me to refer to the manual. The frequency response test was interesting Whereas the specification is for a 3dB roll off at 50. MHz I found no roll off at all on 6 meters, For the overshoot and amp key unkey timing tests I found I could display everything at the same. time When I went to the TRIGGER menu I found that one of the options was triggering on both. negative and positive going slopes of the triggering signal This let me look at the amp key. HSEND going low on transmit and high on un key and the resultant RF signal including. overshoot The resulting timing waveform is shown in Figure 10 The blue trace is the amp. enable disable HSEND line out of the IC 706MKIIG, Figure 10 Amp enable to RF to amp disable timing Again note the first dit overshoot.
However I also tested the overshoot and amp disable timing separately so as to provide detail. similar with the Tektronix TBS1042 tests I enabled the vertical cursors in both cases so as to. more easily display the time Figure 11 shows the first dit overshoot which lasts less than 2ms. And Figure 12 shows the amplifier un key timing showing that RF is still being output about. 4ms after the amp key line has gone high, Figure 11 IC 706 Overshoot duration Figure 12 IC 706 amp disable RF out timing. For the final test I attempted a 2 tone test as I d done with the Tektronix unit Figure 13 shows. the time domain 2 tone RF modulated signal Apparently the Rigol DS1052E doesn t have. enough buffer memory depth for the necessary resolution for 2 tone testing the buffer memory. is where the captured samples are stored There is plenty of resolution to show the main signal. and its harmonics but close in signal resolution is not practical. Figure 13 2 tone RF modulated transceiver output,One somewhat off topic observation. I would like to see the ARRL lab measure transceiver overshoot and amplifier enable disable. timing in their equipment reviews These parameters are becoming increasingly important when. interfacing a transceiver to an amplifier especially when the amplifier is solid state. Some final observations, I noticed a few other differences between these two oscilloscopes that are worthy of mentioning. Both oscilloscopes have a 5 7 diagonal color display However you can turn off the right side. menu on the Rigol which provides a little more display area than on the Tektronix The. Tektronix oscilloscope takes about 30 seconds to boot up whereas the Rigol is up and running in. less than 10 seconds Also the Tektronix takes about 30 seconds to save a file to a USB memory. stick whereas the Rigol takes about 1 second And I did like the Rigol s ability to trigger on. both a positive and negative trigger on the same display However the Tektronix oscilloscope s. ability to display a frequency domain 2 tone test spectrum is important to me. Conclusion, For hams that want to step up to the next level of testing troubleshooting and understanding. equipment performance an oscilloscope becomes more of a necessity Fortunately digital. sampling oscilloscopes have become surprisingly affordable The two oscilloscopes discussed. here will provide most of the capabilities desired by the more sophisticated ham at a price that is. easily justifiable,Bottom Line, The two oscilloscopes reviewed here are ideal for hams interested in more serious.
experimenting They both deliver excellent performance at a price comparable to some high end. watt meters on the market, Manufacturer TBS1042 Tektronix Inc 14150 SW Karl Braun Drive P O Box 500. Beaverton OR 97077 www tek com, Maufacturer DS1052E RIGOL Technologies Inc 7401 First Place Suite N Oakwood Village. Oscilloscope IC 25 The Tektronix TBS1042 Like many computers and test instruments today only a condensed version of the manual was enclosed with the TBS1042 The full manual 159 pages is downloadable on line The only accessories provided with the oscilloscope are the 120VAC power cord and a pair of 10 1

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