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11-03-2018, 05:24 PM
My addiction to fine lab instrumentation goes back decades, and have grown up using Tektronix 547 Hybrid Tube/SS scopes with 1A4 4-Ch plugins, a beautiful Tek R5031 Dual Beam Storage Scope (non-plug-in 7000 series instrument), having two 10uV-10V differential inputs + current probe inputs. For years, in spite it's meager 1MHz BW (typical of their high sensitivity Diff Amps produced in their 1A7A, AM502, 7A22 and others), that scope with its phospher storage ability served as a Frequency Analyzer, driven from a Wavetek 185 Log Swp Gen, an HP3575 Gain/Phase Meter, so I was seeing dB vs Log Freq over a wide range...usually just running 20Hz-20kHz with 1 oct/Div displayed, and vertical of 5dB or 10dB/Div.
It also worked really well in Acoustics, where I'd modulate the VCG of the Wavetek 185 to produce warbled-sine sweep, +/- 1/6 oct, and produce great detail that aligned perfectly with 1/3 oct analyzer plots, but showing all of the room details. The Acoustic front end using a Bruel & Kjaer 1/2" 4134 condenser mic feeding a B & K 2607 Measuring Amp to drive the Y-axis of the scope with it's log DC output for 5 or 10 db/div displays (or greater as need dictates). When I needed hard copy, I also had an HP 7045 XY plotter attached.
I still use that aging R5031 scope, but my main instrument on my present bench is a Tek 7633 Storage Scope with 7A26 2-Ch plugins. It still allows X-Y display functions, for my Semiconductor Curve Tracer, Freq response plots & Impedance Plots for quick-and-dirty measurements. I did invest in a LeCroy 7200A Color Digital Scope that has amazing performance, though needs to live on a Tek wide-body Scope Cart. It's one of the few Digital scopes that offer's XY facility. Most Digital Scopes lack that feature.
At present, the only USB-based digital scope/generator package I have is the Velleman PCSGU250. I mostly use that connected to my laptop for generating Bode Plots with it's modest internal Sweep Generator, which lets you do Frequency Response plots out to 1MHz in Log Sweep mode, in 1/n octave steps from 1/1 thru 1/24 Oct increments. Usable dynamic range is around 50-60db. I buffer the front end of the Velleman with an Amber 3501a Audio Analyzer, so I have a wide range low noise differential input. It allows annotating the plots, then exporting them as a pdf file to add to my growing database.
I was alerted to a really nice device from Digilent ....their Analog Discovery 2. This USB device isn't packaged as a stand-alone lab instrument...you have to do that task yourself, but what it contains is absolutely amazing, and will be my next acquisition. It's scope function offers 2-Ch of 14-bit +/- 25V differential inputs 100MS/s, 30MHz+ BW, a 2-Ch ARB Function Gen, Network Analyzer 1Hz-10MHz, Spectrum Analyzer, Logic Analyzer, Pattern Analyzer, 2 programmable power supplies, etc. Find this at: https://reference.digilentinc.com/refere...nce-manual. That package sells for under $300. After proper packaging so it would be like another robust lab instrument on your bench, it would probably cost another $50-$150, depending on how you like your instruments to be.
When I travel to job sites, I have some Tektronix TM-500 series instruments...one being the SC504 80MHZ 2-CH SCOPE. Tiny CRT, but it is in a 3U x 2-module-width box, so has to be small. I normally have an AM502 Diff Amp in the package, though usually just use the spare Amber 3501a Audio Analyzer for the front end.
I've been buying top of the line used instruments for decades, way before the days of ebay. Being a native of Los Angeles, CA, one of the gold mines years ago was the monthly TRW Radio Amateur's Techincal Swap Meet in Redondo Beach, where retired recent tecnology would hit the parking lot at pennies on the dollar for what industry paid. That's been the story of my life....usually one or two generations behind current technology, so as wealthy industry and military unloads their 'then-current- instrumentation' to buy the new generation, it allowed average folk to buy instruments normally costing thousands of dollars for pennies on the dollar.
It also worked really well in Acoustics, where I'd modulate the VCG of the Wavetek 185 to produce warbled-sine sweep, +/- 1/6 oct, and produce great detail that aligned perfectly with 1/3 oct analyzer plots, but showing all of the room details. The Acoustic front end using a Bruel & Kjaer 1/2" 4134 condenser mic feeding a B & K 2607 Measuring Amp to drive the Y-axis of the scope with it's log DC output for 5 or 10 db/div displays (or greater as need dictates). When I needed hard copy, I also had an HP 7045 XY plotter attached.
I still use that aging R5031 scope, but my main instrument on my present bench is a Tek 7633 Storage Scope with 7A26 2-Ch plugins. It still allows X-Y display functions, for my Semiconductor Curve Tracer, Freq response plots & Impedance Plots for quick-and-dirty measurements. I did invest in a LeCroy 7200A Color Digital Scope that has amazing performance, though needs to live on a Tek wide-body Scope Cart. It's one of the few Digital scopes that offer's XY facility. Most Digital Scopes lack that feature.
At present, the only USB-based digital scope/generator package I have is the Velleman PCSGU250. I mostly use that connected to my laptop for generating Bode Plots with it's modest internal Sweep Generator, which lets you do Frequency Response plots out to 1MHz in Log Sweep mode, in 1/n octave steps from 1/1 thru 1/24 Oct increments. Usable dynamic range is around 50-60db. I buffer the front end of the Velleman with an Amber 3501a Audio Analyzer, so I have a wide range low noise differential input. It allows annotating the plots, then exporting them as a pdf file to add to my growing database.
I was alerted to a really nice device from Digilent ....their Analog Discovery 2. This USB device isn't packaged as a stand-alone lab instrument...you have to do that task yourself, but what it contains is absolutely amazing, and will be my next acquisition. It's scope function offers 2-Ch of 14-bit +/- 25V differential inputs 100MS/s, 30MHz+ BW, a 2-Ch ARB Function Gen, Network Analyzer 1Hz-10MHz, Spectrum Analyzer, Logic Analyzer, Pattern Analyzer, 2 programmable power supplies, etc. Find this at: https://reference.digilentinc.com/refere...nce-manual. That package sells for under $300. After proper packaging so it would be like another robust lab instrument on your bench, it would probably cost another $50-$150, depending on how you like your instruments to be.
When I travel to job sites, I have some Tektronix TM-500 series instruments...one being the SC504 80MHZ 2-CH SCOPE. Tiny CRT, but it is in a 3U x 2-module-width box, so has to be small. I normally have an AM502 Diff Amp in the package, though usually just use the spare Amber 3501a Audio Analyzer for the front end.
I've been buying top of the line used instruments for decades, way before the days of ebay. Being a native of Los Angeles, CA, one of the gold mines years ago was the monthly TRW Radio Amateur's Techincal Swap Meet in Redondo Beach, where retired recent tecnology would hit the parking lot at pennies on the dollar for what industry paid. That's been the story of my life....usually one or two generations behind current technology, so as wealthy industry and military unloads their 'then-current- instrumentation' to buy the new generation, it allowed average folk to buy instruments normally costing thousands of dollars for pennies on the dollar.
