开云体育

try , they are not cheap, about $5 ea


Mark <marks@...> wrote:
Hello All,

I am having trouble tracking down a MC1495 or SG1495 or 1826-0437.

Its a 'wideband linear 4-quadrant multiplier' used in the AM and
Amplitude levelling in a 3325A.

Does anyone sell this chip anymore?

Is there a functional / electrical equivalent?

Best regards,
Mark.

PS I have 3x A3 boards, all with the same problem!
Symptom is A-Cal fail, All 3 self test fail.
The voltages around this IC are all wrong.

mcs






---------------------------------
Get easy, one-click access to your favorites. Make Yahoo! your homepage.

At 09:02 AM 11/20/2007, you wrote:

Hello All,

I am having trouble tracking down a MC1495 or SG1495 or 1826-0437.

Its a 'wideband linear 4-quadrant multiplier' used in the AM and
Amplitude levelling in a 3325A.

Does anyone sell this chip anymore?

It has been obsolete for some time.

Although I have never tried this trick in a 3325A, I have used the
Analog Devices AD633 (readily available from DigiKey and others) in
other applications where I originally used the MC1495. It might be
worth some investigation.

I don't think I have the schematics of the 3325A, but if you can post
or email me the appropriate section I can try to sketch something out for you.

John Day
Toronto

Is there a functional / electrical equivalent?

Best regards,
Mark.

PS I have 3x A3 boards, all with the same problem!
Symptom is A-Cal fail, All 3 self test fail.
The voltages around this IC are all wrong.

mcs

Have you tried ebay ?

Mark <marks@...> wrote: Hello All,

I am having trouble tracking down a MC1495 or SG1495 or 1826-0437.

Its a 'wideband linear 4-quadrant multiplier' used in the AM and
Amplitude levelling in a 3325A.

Does anyone sell this chip anymore?

Is there a functional / electrical equivalent?

Best regards,
Mark.

PS I have 3x A3 boards, all with the same problem!
Symptom is A-Cal fail, All 3 self test fail.
The voltages around this IC are all wrong.

mcs






---------------------------------
Be a better pen pal. Text or chat with friends inside Yahoo! Mail. See how.

Hello All,


I am having trouble tracking down a MC1495 or SG1495 or 1826-0437.

Its a 'wideband linear 4-quadrant multiplier' used in the AM and
Amplitude levelling in a 3325A.

Does anyone sell this chip anymore?

Is there a functional / electrical equivalent?


Best regards,
Mark.

PS I have 3x A3 boards, all with the same problem!
Symptom is A-Cal fail, All 3 self test fail.
The voltages around this IC are all wrong.

mcs

Hello marsac1212,

would it be helpful to you if I send you a scanned copy of the 35677A
schematic?

BTW Are you aware of the thread about the HP 35676A/B Transmission
Reflection Kit for the HP 3577?

Regards
Martin

Planning to use mini-circuits
ZASWA-2-50DR

1.- Yes it is absorptive type i.e 50 ohm terminated
2.-The switch is DC coupled, so LF does not seem to be a problem...
likely it is not PIN based.
3.- Isolation is about 90 db in the range of interest... it will
never beat the 100 dB of a mechanical switch but it will last almost
forever....besides that I think I can take care of the isolation with
a 12 term 2 port correction. Given that the 3577A can not do that
type of correction.

a.) the original switch terminates the unused arm in 50ohm, this

condition needs to be fullfilled by your solid state switch as well !

b.) low frequency boundary
many solid state switches are based on GaAs and suffer from

poor low frequency performance, pin switches are even worse, the
solid state switch used in the 85046A for example exhibits poor RF
characteristics below 100KHz

c.) isolation
the mechanical switches have fairly high isolation, get a

datasheet of the Agilent 8763A (this is what they used) your Solid
state switch needs to be equal or better !

marsac1212 <marsac1212@...> wrote:
Hello group:
Does anybody have the service manual of the 35677A S parameter test

set?

All I need to know is what the pin out of the little connector on

the

back?
I am trying to change the internal mechanical coaxial switch for a
solid state one and use the S parameter with my own LF network

analyzer.

---------------------------------
Get easy, one-click access to your favorites. Make Yahoo! your

homepage.

I have read HP's Technical Specifications and comparison of the 8752C
and 8753D. I am confident the 8752C features are sufficient for the
work I'm doing.

So my question for the group is: Are there other factors beyond
technical specifications to consider? For example, is it more
difficult to obtain spare parts and technical documentation on the
8752C compared to the 8753D? Do they share the same (hard to find)
CRT? Does this group have experience in troubleshooting the 8752C?

Thanks,

Jim W4TVI

I looked but couldnt find a source for download online, anyway its not really rocket science, the connector basically only controls a SPDT switch that switches the RF from the source to either the A or B coupler, there is no step attenuator or anything else to control in the box.
When replacing the mechanical with a solid state switch there are a few things you should keep in mind:

a.) the original switch terminates the unused arm in 50ohm, this condition needs to be fullfilled by your solid state switch as well !

b.) low frequency boundary
many solid state switches are based on GaAs and suffer from poor low frequency performance, pin switches are even worse, the solid state switch used in the 85046A for example exhibits poor RF characteristics below 100KHz

c.) isolation
the mechanical switches have fairly high isolation, get a datasheet of the Agilent 8763A (this is what they used) your Solid state switch needs to be equal or better !



marsac1212 <marsac1212@...> wrote:
Hello group:
Does anybody have the service manual of the 35677A S parameter test set?
All I need to know is what the pin out of the little connector on the
back?
I am trying to change the internal mechanical coaxial switch for a
solid state one and use the S parameter with my own LF network analyzer.






---------------------------------
Get easy, one-click access to your favorites. Make Yahoo! your homepage.

Hello group:
Does anybody have the service manual of the 35677A S parameter test set?
All I need to know is what the pin out of the little connector on the
back?
I am trying to change the internal mechanical coaxial switch for a
solid state one and use the S parameter with my own LF network analyzer.

Since many people dont have the $ or the acess to good tools at work
i have taken the time to put together some recomendations for free or
low cost tools to make life easier ! be aware that most tools listed
are for non commercial use only !

1.) Ansoft Designer SV
Good subset of a commercial high $ package, covers layout and EM
Simulation (planar EM ), what im missing is a optimizer function but
has tune function to make up for it, good model database, lots of
models and substrates ! FREE

2.) EM3DS 2.5D EM Simulator, italian company has a freeware version
for download thats limited in size but still usefull.

3.) WIPL-D 3D EM Simulator, freeware version, full version
reasonably priced !

4.) Sonnet Lite
One of the best known names in EM Simulation, very easy to use
tool, several levels of licensing from free version over a $499
version to $$$$$, good tool !

5.) Genesis (Eagleware elanix)
Good starter tool , low cost , worth the money for possible trade
up against MWO !

6.) Quartus Webpack
FPGA Design tools, altera lately added almost all megafunctions
and devices except of a few very high end Stratix devices to the
webpack ! FREE Software

7.) XILINX Webpack
Free

A few words to Microwave CAE, every program is only as good as its
models and the circuit description you provide ! if you design an
amplifier and dont add your ground vias for the source terminals to
your netlist you will never see the light ! linear simulators also
never account for lids and housings effects like those are best
simulated with a EM Simulator tool !
Last but not least you get what you pay for however the advantages of
a high $ product will not show in the low frequency regions, if you
design 3 or 6GHz stuff Genesis will do you as well as ADS or MWO if
you get higher you will quickly feel the pain ! having driven almost
anything from Eagleware over ADS to MWO i can speak out of
experience.

Agreed, assuming the caqpacitors around the YIG tuning circuits are all up to spec. I've seen
one or two (non Ta) go low C.

Best,
-John



Alexander Whiplash wrote:

designing for low phasenoise never has been a trivial task, this especially goes for wideband oscilators such as YIGs, you also have to drive the shielding of the tuning lines almost to a excessive level.

J Forster <jfor@...> wrote: Agreed, assuming the caqpacitors around the YIG tuning circuits are all up to spec. I've seen
one or two (non Ta) go low C.

Best,
-John

Alexander Whiplash wrote:

--- Kuba Ober <ober.14@...> wrote:

...

I think that Bob Pease wrote a good article or two
about ripple rejection for
power supplies. Google for "what's all this ripple
rejection stuff anyway".
He shows how to do it with high voltage supplies
too.

There are many sources of noise that can get onto the
YIG tuning current. Power supply ripple will have
already been knocked down to a very low level in any
piece of HP gear that is working properly. Any
instrument will have a regulated power supply to power
the YIG driver circuits, and those supplies have very
little ripple on their output(s). The YIG driver
itself will have additional power supply rejection,
perhaps 80 dB or more.

The opamps and transistors and even some passive
components in the YIG driver will impose their noise
on the YIG tuning current and cause non-line related
noise. This is usually dealt with by careful design
and choice of components. Often an additional series
RC is placed across the coil to shunt noise currents
away. One can only take that so far before the tuning
performance or loop bandwidth is too much affected.
Units like the 8568 already have these "tricks" and I
don't think that there is any low hanging fruit to be
had in improving phase noise on it or comparable
instruments.

AW

---------------------------------
Get easy, one-click access to your favorites. Make Yahoo! your homepage.

--- Kuba Ober <ober.14@...> wrote:

...

I think that Bob Pease wrote a good article or two
about ripple rejection for
power supplies. Google for "what's all this ripple
rejection stuff anyway".
He shows how to do it with high voltage supplies
too.

There are many sources of noise that can get onto the
YIG tuning current. Power supply ripple will have
already been knocked down to a very low level in any
piece of HP gear that is working properly. Any
instrument will have a regulated power supply to power
the YIG driver circuits, and those supplies have very
little ripple on their output(s). The YIG driver
itself will have additional power supply rejection,
perhaps 80 dB or more.

The opamps and transistors and even some passive
components in the YIG driver will impose their noise
on the YIG tuning current and cause non-line related
noise. This is usually dealt with by careful design
and choice of components. Often an additional series
RC is placed across the coil to shunt noise currents
away. One can only take that so far before the tuning
performance or loop bandwidth is too much affected.
Units like the 8568 already have these "tricks" and I
don't think that there is any low hanging fruit to be
had in improving phase noise on it or comparable
instruments.

AW



____________________________________________________________________________________
Never miss a thing. Make Yahoo your home page.

On Saturday 17 November 2007, lothar baier wrote:

Building a good YIG based synthesizer has its challenges i admitt, first
problem is that usually YIGs are not as good in phasenoise to begin with,
next thing is that you have to design your drivers carefully and use really
low noise powersupplies and filtering,

I think that Bob Pease wrote a good article or two about ripple rejection for
power supplies. Google for "what's all this ripple rejection stuff anyway".
He shows how to do it with high voltage supplies too.

Cheers, Kuba

First off , are you sure that your 8482A is ok ? have you verified operation with another powermeter ? one offender on the 437 as well as other meters is the input connector, if the contacts wear out over time you get problems

Richard <kq6ef@...> wrote: I have a nice HP 437B Power Meter that is not working. It passes self
test OK, But the output from the Sensor (Good 8482A) displayed varies
all over the place. Even after zero preformed on Power meter. I
downloaded the Service manual from the Agilent web site. The manual is
missing what is called the service sheets. BD1 Block Diagrams and the
schematic sheets A3A,A3B,A3C,A4A,A4B,A4C. Anyone have these sheets in
PDF format.

I suspect a problem with the Analog board but would like more info
before I start poking around.

Thanks
Rich KQ6EF






---------------------------------
Never miss a thing. Make Yahoo your homepage.

Do you have the sensor connected to a 50 ohm source (turned off) or pad?
Sometimes an open sensor input can make things jump around especially on
low ranges.

Best,
-John



Richard wrote:

I have a nice HP 437B Power Meter that is not working. It passes self
test OK, But the output from the Sensor (Good 8482A) displayed varies
all over the place. Even after zero preformed on Power meter. I
downloaded the Service manual from the Agilent web site. The manual is
missing what is called the service sheets. BD1 Block Diagrams and the
schematic sheets A3A,A3B,A3C,A4A,A4B,A4C. Anyone have these sheets in
PDF format.

I suspect a problem with the Analog board but would like more info
before I start poking around.

Thanks
Rich KQ6EF

Ok i know i sound like a broken record but i still consider the 70000
series the best choice if you need a good lab analyzer.
First off its a synthesized unit and you can piece it together and
expand it as needed, the lowest RF gets you to 2.9GHz and you can add
color display plus they are cheap !

If you only need 1.5GHz go for a 8568A or B need to go higher and dont
want to mess with modules buy a 8566 !

In my sincere opinion there is really no more excuse for somebody to
mess with a unit thats not synthesized, the difference in price is not
this much anymore and the performance and stability is just alot better.
I have worked with 8590 series analyzers and every one of them was able
to win a marathon :)
When HP build the 8590 they too the basic RF from the 8558 added a
processor board and display and thats it.

Tek 278 and 9 series are nice until you have to fix them, many
adjustments are done in software and the service software, altough it
is available requires lotus measure - good luck finding a copy !
the other downside is that there are many "prototype" units on ebay
that came out of tek and not even tek can service them anymore.

R+S is nice as well but expensive as hell even used, if you can afford
one or find one cheap go for it - you wont be disapointed.

just out of curiosity i would like to study the E4401 and see if it can be hacked to go to 3GHz, Agilent was good about putting features in their units and then limit them by Firmware corrections, i would not be surprised if the E4401 actually has all the RF to go to 3GHz but is just limited by firmware.
I wouldnt downgrade from a E44 to a 8590 the E44 as far as i know are at least synthesized, the problem with the downconverter approach is that you only have 0-1.5GHz to work with, in order to get a decent image rejection you would not be able to utilize the full band so you end up only beein able to look at a fairly narrow band.
70000 Systems to 2.9GHz are fairly cheap, or you can go for a 8560 or 8561

John Miles <jmiles@...> wrote:
What's your budget like? What features do you actually need?

If you are OK with your current model except for its upper tuning limit,
have you thought about building a downconverter for it? There may even be
frequency-offset and amplitude-offset features in the E4401B's firmware that
will adjust the display to account for an external oscillator and mixer.

If you want calibrated >1.5 GHz coverage in one box but don't want to spend
much money, you'll have to ask yourself what firmware features you're
willing to give up. Switching to an 8590-series analyzer would get you a
higher frequency limit and similar RF performance, but it's an older product
line with fewer bells and whistles. An 8560A or 8560E would be the next
step up in price, and actually a much-better piece of gear from an RF
standpoint, but again it would be missing some newer firmware features.

-- john, KE5FX

Hi.
A few years ago I had the opportunity to purchase a used E4401B
Spectrum analyzer which has worked well for me. I am now interested in
looking as signals between 1.5 and 2 GHz which this analyzer will not
handle. Any suggestions.
Thanks.

---------------------------------
Get easy, one-click access to your favorites. Make Yahoo! your homepage.

What's your budget like? What features do you actually need?

If you are OK with your current model except for its upper tuning limit,
have you thought about building a downconverter for it? There may even be
frequency-offset and amplitude-offset features in the E4401B's firmware that
will adjust the display to account for an external oscillator and mixer.

If you want calibrated >1.5 GHz coverage in one box but don't want to spend
much money, you'll have to ask yourself what firmware features you're
willing to give up. Switching to an 8590-series analyzer would get you a
higher frequency limit and similar RF performance, but it's an older product
line with fewer bells and whistles. An 8560A or 8560E would be the next
step up in price, and actually a much-better piece of gear from an RF
standpoint, but again it would be missing some newer firmware features.

-- john, KE5FX