Tektronix purchased Keithley, broke my instruments?

[Steve Wilson]

Steve Wilson <no@spam.com> wrote:

8753D? That's only 6GHz. I'm sure I have seen detailed instructions for
a wideband network analyzer that covers that range.

See "Cheap homemade 30 MHz - 6 GHz vector network analyzer"

http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyzer.html

It would be easy to extend the range down to 30 Hz.

 

[Cursitor Doom]

On Thu, 04 Jul 2019 03:36:22 -0700, Winfield Hill wrote:

Maybe my real problem is the web app my browser is running (served by
the instrument) isn't recognizing Java running on my system. Could
there be a 32-bit / 64-bit issue?
In the past, my computer was running 32-bit Windows.

People laugh at me still using my mirror galvanometer, but at least I
never get caught out by software issues.
Seriously, there's much to be said for classic test equipment.




--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

 

[Cursitor Doom]

On Thu, 04 Jul 2019 14:25:45 +0000, Steve Wilson wrote:

Or the electrolytics may have dried out and need replacement. This can
be a massive problem.

Why??

 

[Chris Jones]

On 05/07/2019 05:19, Steve Wilson wrote:

Steve Wilson <no@spam.com> wrote:

8753D? That's only 6GHz. I'm sure I have seen detailed instructions for
a wideband network analyzer that covers that range.

See "Cheap homemade 30 MHz - 6 GHz vector network analyzer"

http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyzer.html

It would be easy to extend the range down to 30 Hz.

Of all the public designs on the internet, I think that is the best one.

To measure high isolation values (e.g. filters with high rejection in
the stop band), some more serious shielding metalwork, and isolation of
other coupling paths e.g. via supplies and via LO distribution, will be
needed. It would be fun to work on that.

 

[Steve Wilson]

Chris Jones <lugnut808@spam.yahoo.com> wrote:

On 05/07/2019 05:19, Steve Wilson wrote:
Steve Wilson <no@spam.com> wrote:

8753D? That's only 6GHz. I'm sure I have seen detailed instructions
for a wideband network analyzer that covers that range.

See "Cheap homemade 30 MHz - 6 GHz vector network analyzer"

http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyzer.
html

It would be easy to extend the range down to 30 Hz.

Of all the public designs on the internet, I think that is the best one.

To measure high isolation values (e.g. filters with high rejection in
the stop band), some more serious shielding metalwork, and isolation of
other coupling paths e.g. via supplies and via LO distribution, will be
needed. It would be fun to work on that.

Yes, it looks pretty good. I'd go for a 120 dB log amp converter on the
output. One tricky thing is the directional couplers. I'd look to
Minicircuits. They have a promo going for components for a VNA. Not cheap.

 

[Clifford Heath]

On 5/7/19 2:40 pm, Steve Wilson wrote:

Chris Jones <lugnut808@spam.yahoo.com> wrote:

On 05/07/2019 05:19, Steve Wilson wrote:
Steve Wilson <no@spam.com> wrote:

8753D? That's only 6GHz. I'm sure I have seen detailed instructions
for a wideband network analyzer that covers that range.

See "Cheap homemade 30 MHz - 6 GHz vector network analyzer"

http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyzer.
html

It would be easy to extend the range down to 30 Hz.

Of all the public designs on the internet, I think that is the best one.

To measure high isolation values (e.g. filters with high rejection in
the stop band), some more serious shielding metalwork, and isolation of
other coupling paths e.g. via supplies and via LO distribution, will be
needed. It would be fun to work on that.

Yes, it looks pretty good. I'd go for a 120 dB log amp converter on the
output. One tricky thing is the directional couplers. I'd look to
Minicircuits. They have a promo going for components for a VNA. Not cheap.

The couplers that follow Joel Dunsmore's invention are much more lossy,
being resistive bridges, but if you can deal with that, it's easy to get
good directionality from 300KHz up to 3GHz just by improving a $12
Chinese special. I know that, because I've done it - data on request I
haven't published it yet. Versions of Dunsmore's coupler have been built
that work from 100KHz to over 13GHz.

Clifford Heath.

 

[Steve Wilson]

Clifford Heath <no.spam@please.net> wrote:

On 5/7/19 2:40 pm, Steve Wilson wrote:
Chris Jones <lugnut808@spam.yahoo.com> wrote:

On 05/07/2019 05:19, Steve Wilson wrote:
Steve Wilson <no@spam.com> wrote:

8753D? That's only 6GHz. I'm sure I have seen detailed instructions
for a wideband network analyzer that covers that range.

See "Cheap homemade 30 MHz - 6 GHz vector network analyzer"

http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyze
r. html

It would be easy to extend the range down to 30 Hz.

Of all the public designs on the internet, I think that is the best
one.

To measure high isolation values (e.g. filters with high rejection in
the stop band), some more serious shielding metalwork, and isolation
of other coupling paths e.g. via supplies and via LO distribution,
will be needed. It would be fun to work on that.

Yes, it looks pretty good. I'd go for a 120 dB log amp converter on the
output. One tricky thing is the directional couplers. I'd look to
Minicircuits. They have a promo going for components for a VNA. Not
cheap.

The couplers that follow Joel Dunsmore's invention are much more lossy,
being resistive bridges, but if you can deal with that, it's easy to get
good directionality from 300KHz up to 3GHz just by improving a $12
Chinese special. I know that, because I've done it - data on request I
haven't published it yet. Versions of Dunsmore's coupler have been built
that work from 100KHz to over 13GHz.

Clifford Heath.

Thanks. That led to a wealth of downloads on Dunsmore's work. I have seen
loss figures of 1.6dB, which is not bad. Forstén measured around 1.3 dB at
6 GHz. So Dunsmore seems to ne the way to go.

BTW, the 120 dB log amp is the AD8307. See "Figure 42. 120 dB Measurement
System:

https://www.analog.com/media/en/technical-documentation/data-
sheets/AD8307.pdf

Newer devices are available.

 

[RBlack]

On 3 Jul 2019 18:44:56 -0700, Winfield Hill (winfieldhill@yahoo.com)
said:

Trying to get my Keithley 2600-series SMU
instruments to work with my browser and
Java, I keep getting an error message,

"Blocked by Content Security Policy
An error occurred during a connection to www.tek.com."

"Firefox prevented this page from loading
in this way because the page has a content
security policy that disallows it."

I can't find any way to disable blocking.
The browser doesn't show that a block even
occurred, so I can't add an exception.

Last time I ran these instruments using Java
was about when Tektronix purchased Keithley.

I didn't know my local communication process
was contacting the factory, and some website.
How do the browser and instrument even know
about Tektronix? Re-routing Keithley.com?

I have $35k tied up in these instruments!

FWIW I had a very similar problem with an Agilent DMM, the 34410A. This
has an embedded web server, but it needs the Java runtime environment
installed on the client machine. At some point the version of Java
baked into the instrument got blocked by most of the browsers as it was
full of security holes, initially you could add specific URLs to a
white-list but eventually that was closed as well.

The DMM also talks SCPI over GPIB, so I bought a GPIB-USB adapter from
Prologix, apart from the virtual-COM-port driver the only software
needed is a serial terminal. Prologix also do a GPIB-Ethernet adapter
http://prologix.biz/gpib-ethernet-controller.html

It's supposed to be possible to use SCPI via the LAN port on the 34410A,
but I've never figured out how. The manual is silent on this matter.
The recommended way to use the LAN or USB ports (using Agilent's
proprietary protocols, not SCPI) involves installing hundreds of megs of
bloatware on your PC. No thanks.

If you are happy writing your own scripts to control the instruments
this is the way I would go. If you want the 'virtual instrument
display' offered by the Web interface this would be a lot more work to
replicate.

 

[Clifford Heath]

On 5/7/19 5:28 pm, Steve Wilson wrote:

Clifford Heath <no.spam@please.net> wrote:

On 5/7/19 2:40 pm, Steve Wilson wrote:
Chris Jones <lugnut808@spam.yahoo.com> wrote:

On 05/07/2019 05:19, Steve Wilson wrote:
Steve Wilson <no@spam.com> wrote:

8753D? That's only 6GHz. I'm sure I have seen detailed instructions
for a wideband network analyzer that covers that range.

See "Cheap homemade 30 MHz - 6 GHz vector network analyzer"

http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyze
r. html

It would be easy to extend the range down to 30 Hz.

Of all the public designs on the internet, I think that is the best
one.

To measure high isolation values (e.g. filters with high rejection in
the stop band), some more serious shielding metalwork, and isolation
of other coupling paths e.g. via supplies and via LO distribution,
will be needed. It would be fun to work on that.

Yes, it looks pretty good. I'd go for a 120 dB log amp converter on the
output. One tricky thing is the directional couplers. I'd look to
Minicircuits. They have a promo going for components for a VNA. Not
cheap.

The couplers that follow Joel Dunsmore's invention are much more lossy,
being resistive bridges, but if you can deal with that, it's easy to get
good directionality from 300KHz up to 3GHz just by improving a $12
Chinese special. I know that, because I've done it - data on request I
haven't published it yet. Versions of Dunsmore's coupler have been built
that work from 100KHz to over 13GHz.

Clifford Heath.

Thanks. That led to a wealth of downloads on Dunsmore's work. I have seen
loss figures of 1.6dB, which is not bad. ForstĂŠn measured around 1.3 dB at
6 GHz. So Dunsmore seems to ne the way to go.

Dunsmore's bridge has unequal legs to achieve low loss. One leg has
non-ideal ferrite, and the matching leg cannot do anything to cancel that.

Paul McMahon VK3DIP figured out that you can cancel the non-ideal
reactance of the ferrite, but it only works for an equal-sided bridge
(6dB loss). This product I have
<https://www.aliexpress.com/item/32956081266.html> is an
incorrectly-constructed clone of a Ukrainian version of Paul's design.
After fitting the missing link to correct the circuit, and changing the
100R resistor pairs to 50R, replacing the badly-fitted coax to
semi-rigid line, etc, it had directivity better than 45dB from 300KHz to
320MHz, 40dB to 600MHz, 30dB to about 1GHz, and still almost 20dB at
2.4GHz. Gotta be pretty happy at that price! Smaller and better geometry
(0402 resistors, etc) can push the top end way up - this was poorly
constructed on FR4.

Clifford Heath.

 

[Jeroen Belleman]

RBlack wrote:

On 3 Jul 2019 18:44:56 -0700, Winfield Hill (winfieldhill@yahoo.com)
said:
Trying to get my Keithley 2600-series SMU
instruments to work with my browser and
Java, I keep getting an error message,

"Blocked by Content Security Policy
An error occurred during a connection to www.tek.com."

"Firefox prevented this page from loading
in this way because the page has a content
security policy that disallows it."

I can't find any way to disable blocking.
The browser doesn't show that a block even
occurred, so I can't add an exception.

Last time I ran these instruments using Java
was about when Tektronix purchased Keithley.

I didn't know my local communication process
was contacting the factory, and some website.
How do the browser and instrument even know
about Tektronix? Re-routing Keithley.com?

I have $35k tied up in these instruments!


FWIW I had a very similar problem with an Agilent DMM, the 34410A. This
has an embedded web server, but it needs the Java runtime environment
installed on the client machine. At some point the version of Java
baked into the instrument got blocked by most of the browsers as it was
full of security holes, initially you could add specific URLs to a
white-list but eventually that was closed as well.

The DMM also talks SCPI over GPIB, so I bought a GPIB-USB adapter from
Prologix, apart from the virtual-COM-port driver the only software
needed is a serial terminal. Prologix also do a GPIB-Ethernet adapter
http://prologix.biz/gpib-ethernet-controller.html

It's supposed to be possible to use SCPI via the LAN port on the 34410A,
but I've never figured out how. The manual is silent on this matter.
The recommended way to use the LAN or USB ports (using Agilent's
proprietary protocols, not SCPI) involves installing hundreds of megs of
bloatware on your PC. No thanks.

If you are happy writing your own scripts to control the instruments
this is the way I would go. If you want the 'virtual instrument
display' offered by the Web interface this would be a lot more work to
replicate.

Yes, that's the way I see things too. If the instrument has a LAN
port, use it. If the instrument has only GPIB, use a Prologix
GPIB-Ethernet adapter and proceed as before. I'm very happy with
that little gadget. I used to have a National Instruments GPIB
ethernet bridge. That was expensive, required a proprietary driver
and associated API library and stopped working after an OS update.
Never again.

I write my own scripts. Some instruments have weirdnesses making
life a little harder, but I always end up making things work.

Jeroen Belleman

 

When did this happen ?

Now take that date and remember it.

Now go to the thingie in Windows and find out whenever whatever update happened that coincides with the date of your problem.

Then you can draw your own conclusions.

Want mine ?

 

[Phil Hobbs]

On 7/4/19 3:06 PM, Steve Wilson wrote:

Jeroen Belleman <jeroen@nospam.please> wrote:

Steve Wilson wrote:
Jeroen Belleman <jeroen@nospam.please> wrote:

Steve Wilson wrote:

Isn't there any other way to run your instruments?

Yes. It's likely to understand SCPI as well, hopefully
without needing binary transfers, which I still haven't figured out.

Jeroen Belleman

In most cases, I like to make my own instrumentation. Modern chips have
become so powerful, it is often difficult to find an old Tektronix or
HP instrument that can match them.

This approach is much more flexible. You can tailor the measurement to
the actual need, and change it at any time. You can rarely modify any
existing instrument for custom requirements.

I suppose we all do that, to some extent. But I can't easily
match the performance of an HP8753D network analyzer, or a
Tektronix S-6 sampler, so I'll keep using those for as long
as I can. It's not so very long ago that it occurred to me
that I could use a DAC and an ADC to control the Tek 7T11
and 7S11 plug-ins, so I now have a 10GHz digital scope/TDR
that's almost half a century old. That's hugely better than
taking pictures of the screen!

I also hate it when instrument manufacturers try to tie my
hands. I'll refuse to buy any new National Instruments,
Lecroy or anything running Windows or requiring special
opaque driver software for that reason.

Instruments, even of reputable manufacturers, often have
weird limitations. The HP8753D, for example, delivers
measured data as complex pairs *without* the frequency
data. My Tabor WW1071 AWG has gaussian or sinc pulses
right way up, but *not* upside-down. The hardware can do
it easily enough, but the software botches it. Snarl!

Jeroen Belleman

8753D? That's only 6GHz. I'm sure I have seen detailed instructions for a
wideband network analyzer that covers that range. A cheap log amp gives
amplitude with a 120 DB range, plus phase information. Output in whatever
format you like. It's well within reach to anyone who is used to building
their own receivers and who can work with low level signals. That's on my
ToDo list.

The S-6 sampler only goes to 11.5 GHz. I can beat that.

I'd be interested in some of your designs, then. Could you post some?

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

RBlack <news@rblack01.plus.com> wrote in
news:MPG.37890ea8d2a8918a9896a1@reader80.eternal-september.org:

On 3 Jul 2019 18:44:56 -0700, Winfield Hill
(winfieldhill@yahoo.com) said:
Trying to get my Keithley 2600-series SMU
instruments to work with my browser and
Java, I keep getting an error message,

"Blocked by Content Security Policy
An error occurred during a connection to www.tek.com."

"Firefox prevented this page from loading
in this way because the page has a content
security policy that disallows it."

I can't find any way to disable blocking.
The browser doesn't show that a block even
occurred, so I can't add an exception.

Last time I ran these instruments using Java
was about when Tektronix purchased Keithley.

I didn't know my local communication process
was contacting the factory, and some website.
How do the browser and instrument even know
about Tektronix? Re-routing Keithley.com?

I have $35k tied up in these instruments!


FWIW I had a very similar problem with an Agilent DMM, the 34410A.
This has an embedded web server, but it needs the Java runtime
environment installed on the client machine. At some point the
version of Java baked into the instrument got blocked by most of
the browsers as it was full of security holes, initially you could
add specific URLs to a white-list but eventually that was closed
as well.

The DMM also talks SCPI over GPIB, so I bought a GPIB-USB adapter
from Prologix, apart from the virtual-COM-port driver the only
software needed is a serial terminal. Prologix also do a
GPIB-Ethernet adapter
http://prologix.biz/gpib-ethernet-controller.html

It's supposed to be possible to use SCPI via the LAN port on the
34410A, but I've never figured out how. The manual is silent on
this matter. The recommended way to use the LAN or USB ports
(using Agilent's proprietary protocols, not SCPI) involves
installing hundreds of megs of bloatware on your PC. No thanks.

If you are happy writing your own scripts to control the
instruments this is the way I would go. If you want the 'virtual
instrument display' offered by the Web interface this would be a
lot more work to replicate.

I still say he is trying to connect thru IPV6, which at one point
was set up as the java default, and getting rejected at his ISP.

IPV4 works.

 

[Chris Jones]

On 05/07/2019 17:28, Steve Wilson wrote:

Clifford Heath <no.spam@please.net> wrote:

On 5/7/19 2:40 pm, Steve Wilson wrote:
Chris Jones <lugnut808@spam.yahoo.com> wrote:

On 05/07/2019 05:19, Steve Wilson wrote:
Steve Wilson <no@spam.com> wrote:

8753D? That's only 6GHz. I'm sure I have seen detailed instructions
for a wideband network analyzer that covers that range.

See "Cheap homemade 30 MHz - 6 GHz vector network analyzer"

http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyze
r. html

It would be easy to extend the range down to 30 Hz.

Of all the public designs on the internet, I think that is the best
one.

To measure high isolation values (e.g. filters with high rejection in
the stop band), some more serious shielding metalwork, and isolation
of other coupling paths e.g. via supplies and via LO distribution,
will be needed. It would be fun to work on that.

Yes, it looks pretty good. I'd go for a 120 dB log amp converter on the
output. One tricky thing is the directional couplers. I'd look to
Minicircuits. They have a promo going for components for a VNA. Not
cheap.

The couplers that follow Joel Dunsmore's invention are much more lossy,
being resistive bridges, but if you can deal with that, it's easy to get
good directionality from 300KHz up to 3GHz just by improving a $12
Chinese special. I know that, because I've done it - data on request I
haven't published it yet. Versions of Dunsmore's coupler have been built
that work from 100KHz to over 13GHz.

Clifford Heath.

Thanks. That led to a wealth of downloads on Dunsmore's work. I have seen
loss figures of 1.6dB, which is not bad. ForstĂŠn measured around 1.3 dB at
6 GHz. So Dunsmore seems to ne the way to go.

BTW, the 120 dB log amp is the AD8307. See "Figure 42. 120 dB Measurement
System:

Log amps are fine if you need to measure changes in power level with an
accuracy of maybe 1dB or a bit better, but if you need to measure a
change in power level with an accuracy of say 0.01dB then a mixer and
ADC is a much better approach.

The reason is this: log amps like the AD8307 work by cascading a lot of
amplifier stages and then putting a rectifier on each stage, and summing
the outputs of the rectifiers. This works pretty well, but if you plot
the output signal (voltage) vs. the input power in dB, then you see a
periodic ripple, with a small bump every few dB, spaced according to how
much gain per stage is used in the log amp. That is why the AD8307 has a
"log conformance +/-0.3dB typical, +/-1.0dB max" specification.

In a manual scalar network analyser where you just plot the response on
an oscilloscope, the log amp would be fine (at low frequencies anyway)
as you probably don't care to measure the response of a filter better
than a dB or so. Without calibration to correct for impedance
mismatching on your VNA ports you are not going to be able to check the
steps on an attenuator to 0.01dB or stuff like that anyway.

In a VNA where you want to use computer correction and calibration to
take out the effects of the cables and imperfect matching, it is
necessary to measure the relative amplitude of signals with much better
accuracy. e.g. if your connectors produce reflections at -20dB, but you
can measure this error and subtract it out digitally, then you can still
measure the return loss of a DUT at say -40dB, perhaps with 0.1dB
precision or better. This relies on being able to subtract two fairly
large signals, and accurately determine the difference between them,
which is much smaller. Having 0.3dB of ripple in the transfer function
of the log amp really screws up this subtraction. There might be ways to
characterise it, but it is temperature dependent too. You could put it
in a thermstatic oven, but it is frequency dependent too. A mixer can be
more linear with amplitude, provided it is not overdriven on the RF
port, for which it helps to drive the LO port really hard with
approximately a square wave.

Similarly, you can make a 16-bit audio DAC with 5% resistors, and if you
toggle the LSB, the signal will be about 96dB smaller than if you toggle
all of the bits together, so you could say that it has 96dB of dynamic
range, but you will not like the distortion when you play music through it.

Log amps are also inherently wideband, so they measure the noise in a
wide bandwidth, which limits dynamic range. Only by filtering part-way
along the log-amp can this be fixed. Note the 10.7MHz bandpass filter in
fig. 42, and so that circuit is only good for a 10.7MHz VNA! You will
need a mixer for other frequencies, and then you might as well follow it
with a nice, high resolution ADC which will give you very precise
measurements across a very wide dynamic range.

For a hobbyist VNA, I see no need for a high IF frequency, and isolation
on the PCB is easier to achieve at low frequencies. I was thinking of
using an IF at a few kHz and an AD7608 ADC, because for VNAs you are
interested in the ratio of the channel gains, and the relative phase
shifts between receiver channels. Having all ADC channels on the one
chip, with simultaneous sampling, and with the anti-aliasing filters on
the same chip so that the cutoff frequencies are well matched, should be
useful here. Also, there are enough channels to make a 4-port VNA with
two mixers per port, using just one ADC chip which I think would help to
provide good value for money.

I was intending to try using LT5560 for the mixers. I have a theory that
using the two RF input pins separately rather than as a single
differential port, would allow two RF signals to be directly subtracted,
which is useful if you are building directional bridges with resistor
networks rather than making stripline or Dunsmore style directional
couplers. Resistive bridges are wideband and very small, which again
helps with cost. I got this idea from:
http://sdr-kits.net/documents/Baier_VNWA2_QEX.pdf
though I don't like his idea of driving mixers with simusoidal LO - this
makes them more temperature sensitive - nor do I like the idea of mixing
using DDS DAC images. Square wave LO and using harmonic mixing to extend
the frequency range should give more stable performance vs. temperature.
I suspect that with the LO port driven nice and hard with a differential
square-ish wave, the LT5560 would mix to a usable extent at the 3rd
harmonic of its LO frequency, perhaps extending coverage well above 4GHz.

I got someone to decap some LT5560 and image them for me, so I could
check the internal connections - I wanted to drive the LO port
differentially, and bias the RF port with DC coupling.

I think the LO distribution to the mixers could be done with something
like a ADCLK948, though I need to check how much isolation is needed in
the LO path between the ADCLK948 and each mixer. If one mixer is
measuring a RF signal 100dB above the signal that another mixer is
measuring, it is foreseeable that coupling from the RF port of a mixer
to its LO port through the LO traces and between the bondwires of the
ADCLK948 and then to the LO port of another mixer and then to its RF
port, could limit accuracy. Adding an individual LO buffer for each
mixer would be undesirable for cost/space reasons and also because any
temperature difference between the separate LO buffers will cause phase
skew between receiver channels.

Each mixer would probably want its own screening can. Maybe a Wuerth
36103205 frame and 36003200 lid.

I was intending to put an AD8253 between the output of each mixer and
its corresponding ADC channel on the AD7608, because the channel to
channel isolation of the AD7608 might otherwise limit dynamic range. The
gain steps of the AD8253 are very accurate and stable. Each AD8253 could
be inside the same can with its mixer, so that very tiny baseband
signals don't have to traverse the whole PCB near bigger ones.

The LO could come from one of the ADF4351 type things, and be fed to one
input of the ADCLK948. I haven't looked at the newer ones yet. To go to
lower frequencies than the minimum that it can divide to internally, the
extra division stages could be implemented in the system fpga, if
necessary re-clocked to the ADF4351 output using a NB4L52 and then fed
to the other input of the ADCLK948.

The RF stimulus is a more complicated problem, if you care about it
being a sine wave. I'm not sure that it is important, but it would be
nice. I was thinking of using an ADF4351 or its newer relatives, and a
filter bank like the hforsten.com design, however below 50MHz I would
instead feed the PLL chip output into the clock of a DDS like the
AD9954, using the AD9954 only to generate integer fractions of the PLL
frequency. Since the DDS is being used as a divide-by-N, there are no
spurs other than harmonics, but at low frequencies (e.g. audio) the
output is much closer to a sinewave than if the internal divide-by-2^N
of the ADF4351 is used. This might mean that there is no need for
filtering at low frequencies. (The AD9954 is nicer than some newer ones
because it still has the DACBP pin - see:
https://martein.home.xs4all.nl/pa3ake/hmode/dds_ad9910_amnoise.html
)

Since this whole PCB might end up running quite warm, I thought it would
be worth putting some SMD thermistors on it and SMD heater resistors, to
warm it quickly to its final temperature and to slightly ovenise it. The
different mixers could have their own separate heaters and thermistors,
to keep thermal gradients small or at least constant. A microcontroller
could fairly easily run all of those PID loops.

Anyway I got very busy in the last few years so I had no time to make
further progress on designing this VNA.

 

[Winfield Hill]

RBlack wrote...

On 3 Jul 2019, Winfield Hill said:

Trying to get my Keithley 2600-series SMU
instruments to work with my browser and
Java, I keep getting an error message,

"Blocked by Content Security Policy
An error occurred during a connection to www.tek.com."

"Firefox prevented this page from loading
in this way because the page has a content
security policy that disallows it."

Some thought my browser couldn't reach tek.com. But
Java, running the instrument's program, blocked.

FWIW I had a very similar problem with an Agilent DMM,
the 34410A. This has an embedded web server, but it
needs the Java runtime environment installed on the
client machine. At some point the version of Java
baked into the instrument got blocked by most of the
browsers as it was full of security holes, initially
you could add specific URLs to a white-list but
eventually that was closed as well.

OK, it's working now. Modern FireFox & Java no longer
works, so I replicated the old environment: A laptop
with 32-bit Windows 7, delete Firefox and Java. Then
install old FireFox 7: Firefox Setup 7.0.1.exe and a
middle-age version of Java 6: jre-6u45-windows-i586.exe
Later, when Java asks to update itself, disable updates.


--
Thanks,
- Win

 

[Winfield Hill]

Winfield Hill wrote...

OK, it's working now. Modern FireFox & Java no longer
works, so I replicated the old environment: A laptop
with 32-bit Windows 7, delete Firefox and Java. Then
install old FireFox 7: Firefox Setup 7.0.1.exe and a
middle-age version of Java 6: jre-6u45-windows-i586.exe
Later, when Java asks to update itself, disable updates.

As of last Sept 18th, Firefox no longer supports NPAPI,
required for Java applets in the browser. And none of
the 64-bit FireFox versions ever did.

https://www.java.com/en/download/faq/firefox_java.xml


--
Thanks,
- Win

 

[Jeroen Belleman]

Chris Jones wrote:
[...]

Log amps are fine if you need to measure changes in power level [...]

That's a very nice description. We'd love to see more like
it on SED. This makes it worthwhile to stay.

Thanks,
Jeroen Belleman

 

[Steve Wilson]

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

On 7/4/19 3:06 PM, Steve Wilson wrote:

The S-6 sampler only goes to 11.5 GHz. I can beat that.

I'd be interested in some of your designs, then. Could you post some?

Thanks. Not yet. Later.

Cheers

Phil Hobbs

 

[Winfield Hill]

John Robertson wrote...

On 2019/07/05 7:19 a.m., Winfield Hill wrote:
Winfield Hill wrote...

OK, it's working now. Modern FireFox & Java no longer
works, so I replicated the old environment: A laptop
with 32-bit Windows 7, delete Firefox and Java. Then
install old FireFox 7: Firefox Setup 7.0.1.exe and a
middle-age version of Java 6: jre-6u45-windows-i586.exe
Later, when Java asks to update itself, disable updates.

As of last Sept 18th, Firefox no longer supports NPAPI,
required for Java applets in the browser. And none of
the 64-bit FireFox versions ever did.

https://www.java.com/en/download/faq/firefox_java.xml

Have you looked at something like 'LiveConnect'?

https://developer.mozilla.org/en-US/docs/Archive/Mozilla/Java_in_Firefox_Extensions

No, I'll check it out later, off to work now.

I run the latest 64-bit version of Firefox on my Mac and
have no problem viewing the tek.com web site.

This is what was happening. 64-bit Firefox put up the
instrument's web pages, but when I clicked on anything
requiring a Java applet to run, it failed, and the web
program then went to Keithley.com = tek.com for a copy
of Java, but quickly put up a security error message.

Trying 32-bit FireFox and Java also didn't work, since
the new picky FireFox no longer supported Java applets.
It took some experimenting to find the right versions.

The Virtual front panel, and the TSP Express system in
the machine, using the Java applets, is super useful.
I don't believe they in fact create any security risk,
but the world has moved on.

Loading this software combination into a laptop should
work with any 2000 to 2015-era Java web applet machine.


--
Thanks,
- Win

 

[John Robertson]

On 2019/07/05 7:19 a.m., Winfield Hill wrote:

Winfield Hill wrote...

OK, it's working now. Modern FireFox & Java no longer
works, so I replicated the old environment: A laptop
with 32-bit Windows 7, delete Firefox and Java. Then
install old FireFox 7: Firefox Setup 7.0.1.exe and a
middle-age version of Java 6: jre-6u45-windows-i586.exe
Later, when Java asks to update itself, disable updates.

As of last Sept 18th, Firefox no longer supports NPAPI,
required for Java applets in the browser. And none of
the 64-bit FireFox versions ever did.

https://www.java.com/en/download/faq/firefox_java.xml

Have you looked at something like 'LiveConnect'?

https://developer.mozilla.org/en-US/docs/Archive/Mozilla/Java_in_Firefox_Extensions

I run the latest 64-bit version of Firefox on my Mac and have no problem
viewing the tek.com web site. I do have java installed on my machine
(java version "1.8.0_171") even though it appears (as you point out)
that Firefox doesn't use it.

https://java.com/en/download/faq/firefox_java.xml

Is Java actually needed to access tek.com? According to java.com it is
just needed for some applets...

John :-#)#