Composite video amp...

B

bitrex

Guest
Looking for a recommendation for a voltage-feedback op amp suitable for
buffering/amplifying composite video signals, not a portable application
so +5/-5 supply is OK. An amp that can drive 75 ohms directly is nice
but not required I can always add a buffer. Something around $1.50 in
quantity?

There\'s a lot to choose from and not everything lists differential gain
and differential phase up-front so a recommendation would be nice
 
On 10/5/2020 11:48 PM, bitrex wrote:
Looking for a recommendation for a voltage-feedback op amp suitable for
buffering/amplifying composite video signals, not a portable application
so +5/-5 supply is OK. An amp that can drive 75 ohms directly is nice
but not required I can always add a buffer. Something around $1.50 in
quantity?

There\'s a lot to choose from and not everything lists differential gain
and differential phase up-front so a recommendation would be nice
Click to expand...

Differential gain and phase error, rather
 
bitrex wrote:

===============--
Looking for a recommendation for a voltage-feedback op amp suitable for
buffering/amplifying composite video signals, not a portable application
so +5/-5 supply is OK. An amp that can drive 75 ohms directly is nice
but not required I can always add a buffer. Something around $1.50 in
quantity?


** The uA733 fits your spec, Digikey have lots in various paks inc SMD.
Click to expand...

The data sheet says it hails from 1970, so maybe a bit old hat for you.

I know it cos there are a couple in my 50MHz dual trace scope providing most of the vertical gain.


..... Phil
 
On 10/6/2020 12:22 AM, Phil Allison wrote:
bitrex wrote:

===============--
Looking for a recommendation for a voltage-feedback op amp suitable for
buffering/amplifying composite video signals, not a portable application
so +5/-5 supply is OK. An amp that can drive 75 ohms directly is nice
but not required I can always add a buffer. Something around $1.50 in
quantity?


** The uA733 fits your spec, Digikey have lots in various paks inc SMD.

The data sheet says it hails from 1970, so maybe a bit old hat for you.

I know it cos there are a couple in my 50MHz dual trace scope providing most of the vertical gain.


.... Phil
Click to expand...

Wow, magnetic tape or disc-file systems. I\'m picturing one of those big
cabinets with spinning tape mass storage for mainframe computers.

Amazing it\'s still being made and in relatively large quantity, even.
All transistors inside look to be NPN, maybe the design dates from the
time when it wasn\'t cheap to put PNPs on an IC. problem is it\'s not
really suitable for use as a buffer amp/line driving.

I just noticed NJR seems to make a bespoke chip for that \"and is
suitable for low power design on downsizing of Car camera and CCTV.\"

<https://www.mouser.com/datasheet/2/294/NJM2561_E-1375659.pdf>

and includes the 6dB voltage gain to compensate for the termination
divider action.

The application is something like that, buffering the output of a video
multiplexer into an isolation transformer. There\'s an EDN article on how
to set the output impedance using feedback rather than in-line
resistance but needs an op-amp type of amplifier that can have arbitrary
gain:

<https://www.edn.com/save-3-db-of-output-power-using-feedback-to-set-the-output-impedance/>
 
On 10/6/2020 5:32 AM, bitrex wrote:

Dual-boot Linux and Windows can\'t figure out what time it is :(
 
On 10/5/2020 11:48 PM, bitrex wrote:
Looking for a recommendation for a voltage-feedback op amp suitable for
buffering/amplifying composite video signals, not a portable application
so +5/-5 supply is OK. An amp that can drive 75 ohms directly is nice
but not required I can always add a buffer. Something around $1.50 in
quantity?

There\'s a lot to choose from and not everything lists differential gain
and differential phase up-front so a recommendation would be nice
Click to expand...

Neat, Linear/AD actually makes the thing I need all integrated into one
chip, a 3-input video multiplexer + line driver:

<https://www.mouser.com/ProductDetail/Analog-Devices/LT6559CUDPBF?qs=hVkxg5c3xu%2FSkXiqmdItxQ%3D%3D>

not much more than $1 in quantity, surprisingly.
 
On 2020-10-06, bitrex <user@example.net> wrote:
On 10/6/2020 5:32 AM, bitrex wrote:

Dual-boot Linux and Windows can\'t figure out what time it is :(
Click to expand...

Set both to use the hardware clock as GMT

--
Jasen.
 
bitrex = a complete dope wrote:

==================================
Phil Allison wrote:

** The uA733 fits your spec, Digikey have lots in various paks inc SMD.

The data sheet says it hails from 1970, so maybe a bit old hat for you.

I know it cos there are a couple in my 50MHz dual trace scope
providing most of the vertical gain.

..

Amazing it\'s still being made and in relatively large quantity,
Click to expand...

** Must be very special - right ?


problem is it\'s not really suitable for use as a buffer amp/line driving.
Click to expand...

** Read you own post - fuckhead.

What does it say about buffering a low impedance?

( Wot a vile, pathetic cretin )


...... Phil
 
On 10/6/2020 8:36 AM, Phil Allison wrote:
bitrex = a complete dope wrote:

==================================
Phil Allison wrote:


** The uA733 fits your spec, Digikey have lots in various paks inc SMD.

The data sheet says it hails from 1970, so maybe a bit old hat for you.

I know it cos there are a couple in my 50MHz dual trace scope
providing most of the vertical gain.

.

Amazing it\'s still being made and in relatively large quantity,

** Must be very special - right ?


problem is it\'s not really suitable for use as a buffer amp/line driving.


** Read you own post - fuckhead.

What does it say about buffering a low impedance?

( Wot a vile, pathetic cretin )


..... Phil
Click to expand...

Asked for an \"op amp.\" There are suitable op amps that can drive coax
and ones that can\'t. The uA733 isn\'t even an op amp.

Must be a slow day for you bro because you are reaching
 
On Tuesday, October 6, 2020 at 11:13:58 AM UTC-4, bitrex wrote:
Asked for an \"op amp.\" There are suitable op amps that can drive coax
and ones that can\'t. The uA733 isn\'t even an op amp.

Must be a slow day for you bro because you are reaching
Click to expand...

Analog Devices make Op-Amps for HD TV that drive coax with over 350 MHz bandwidth. I have some Grass Valley and some Extron video DAs that use them. I can pull one to get the part numbers, if needed. I can\'t access my external drive with my design notes right now. I\'m still having electrical problems. That computer is on a circuit that was fried. I convert the video DAs to 50 ohm for 10MHz DAs
 
On 10/6/2020 12:18 PM, Michael Terrell wrote:
On Tuesday, October 6, 2020 at 11:13:58 AM UTC-4, bitrex wrote:

Asked for an \"op amp.\" There are suitable op amps that can drive coax
and ones that can\'t. The uA733 isn\'t even an op amp.

Must be a slow day for you bro because you are reaching

Analog Devices make Op-Amps for HD TV that drive coax with over 350 MHz bandwidth. I have some Grass Valley and some Extron video DAs that use them. I can pull one to get the part numbers, if needed. I can\'t access my external drive with my design notes right now. I\'m still having electrical problems. That computer is on a circuit that was fried. I convert the video DAs to 50 ohm for 10MHz DAs
Click to expand...

Yeah a list of any part #s would be nice, though AD products sometimes
tend to break the bank :)

I was pretty surprised this thinger is only $1 in quantity. I need to
multiplex several signals and drive a cable and it fits the bill:

<https://www.mouser.com/ProductDetail/Analog-Devices/LT6559CUDPBF?qs=hVkxg5c3xu%2FSkXiqmdItxQ%3D%3D>

300MHz bandwidth is probably overkill for standard def composite but
it\'s hard to argue with the price. Honestly lots of inexpensive op amps
have what it takes in theory for the bandwidth and output drive to do
the job for standard-def composite but the ones that do it well have low
differential gain and phase error
 
On Tuesday, October 6, 2020 at 2:08:07 PM UTC-4, bitrex wrote:
On 10/6/2020 12:18 PM, Michael Terrell wrote:
On Tuesday, October 6, 2020 at 11:13:58 AM UTC-4, bitrex wrote:

Asked for an \"op amp.\" There are suitable op amps that can drive coax
and ones that can\'t. The uA733 isn\'t even an op amp.

Must be a slow day for you bro because you are reaching

Analog Devices make Op-Amps for HD TV that drive coax with over 350 MHz bandwidth. I have some Grass Valley and some Extron video DAs that use them. I can pull one to get the part numbers, if needed. I can\'t access my external drive with my design notes right now. I\'m still having electrical problems. That computer is on a circuit that was fried. I convert the video DAs to 50 ohm for 10MHz DAs

Yeah a list of any part #s would be nice, though AD products sometimes
tend to break the bank :)

I was pretty surprised this thinger is only $1 in quantity. I need to
multiplex several signals and drive a cable and it fits the bill:

https://www.mouser.com/ProductDetail/Analog-Devices/LT6559CUDPBF?qs=hVkxg5c3xu%2FSkXiqmdItxQ%3D%3D

300MHz bandwidth is probably overkill for standard def composite but
it\'s hard to argue with the price. Honestly lots of inexpensive op amps
have what it takes in theory for the bandwidth and output drive to do
the job for standard-def composite but the ones that do it well have low
differential gain and phase error
Click to expand...

As a Broadcast engineer, I was thrilled when RCA introduced a first real video amplifier for NTSC video in 1988. It was flat to 5 MHz, and it could drive 75Ohm coax. All for $10 each, if you could even buy them. A Broadcast DA was over $1000, per channel, with four outputs. That was what Grass Valley started the company with, Video DAs. They eliminated having to loop everything on one output. You had seperate feeds for the transmitter, master monitor and two others to drive less critical loads. No one liked going off air to exchange equipment when a monitor died, in a long loop. They also made DA\'s for synce signals and Chroma.
 
On 10/6/2020 5:19 PM, Michael Terrell wrote:
On Tuesday, October 6, 2020 at 2:08:07 PM UTC-4, bitrex wrote:
On 10/6/2020 12:18 PM, Michael Terrell wrote:
On Tuesday, October 6, 2020 at 11:13:58 AM UTC-4, bitrex wrote:

Asked for an \"op amp.\" There are suitable op amps that can drive coax
and ones that can\'t. The uA733 isn\'t even an op amp.

Must be a slow day for you bro because you are reaching

Analog Devices make Op-Amps for HD TV that drive coax with over 350 MHz bandwidth. I have some Grass Valley and some Extron video DAs that use them. I can pull one to get the part numbers, if needed. I can\'t access my external drive with my design notes right now. I\'m still having electrical problems. That computer is on a circuit that was fried. I convert the video DAs to 50 ohm for 10MHz DAs

Yeah a list of any part #s would be nice, though AD products sometimes
tend to break the bank :)

I was pretty surprised this thinger is only $1 in quantity. I need to
multiplex several signals and drive a cable and it fits the bill:

https://www.mouser.com/ProductDetail/Analog-Devices/LT6559CUDPBF?qs=hVkxg5c3xu%2FSkXiqmdItxQ%3D%3D

300MHz bandwidth is probably overkill for standard def composite but
it\'s hard to argue with the price. Honestly lots of inexpensive op amps
have what it takes in theory for the bandwidth and output drive to do
the job for standard-def composite but the ones that do it well have low
differential gain and phase error

As a Broadcast engineer, I was thrilled when RCA introduced a first real video amplifier for NTSC video in 1988. It was flat to 5 MHz, and it could drive 75Ohm coax. All for $10 each, if you could even buy them. A Broadcast DA was over $1000, per channel, with four outputs. That was what Grass Valley started the company with, Video DAs. They eliminated having to loop everything on one output. You had seperate feeds for the transmitter, master monitor and two others to drive less critical loads. No one liked going off air to exchange equipment when a monitor died, in a long loop. They also made DA\'s for synce signals and Chroma.
Click to expand...

One thing that doesn\'t seem easy to find at reasonable cost nowadays is
a synchronization/\"black burst\" signal-generator chip. That e.g. just
generates the NTSC composite timing pulses but no luminance or chroma so
you get a black raster.

The LM1881 is still made but the LM1882 looks to be gone. The \'1881 can
strip the video from a composite signal if you already have it but
doesn\'t look like it can generate the sync itself.

Renesas does make a cheap chip that can generate the frequencies you\'d
need for different standards from a clock by fractional PLL but you\'d
need some external logic to make a black burst:

<https://www.mouser.com/datasheet/2/698/IDT__DST_20100514_21-1711558.pdf>
 
On Wednesday, October 7, 2020 at 2:13:58 AM UTC+11, bitrex wrote:
On 10/6/2020 8:36 AM, Phil Allison wrote:
bitrex = a complete dope wrote:

==================================
Phil Allison wrote:


** The uA733 fits your spec, Digikey have lots in various paks inc SMD.

The data sheet says it hails from 1970, so maybe a bit old hat for you.

I know it cos there are a couple in my 50MHz dual trace scope
providing most of the vertical gain.

.

Amazing it\'s still being made and in relatively large quantity,

** Must be very special - right ?


problem is it\'s not really suitable for use as a buffer amp/line driving.


** Read you own post - fuckhead.

What does it say about buffering a low impedance?

( Wot a vile, pathetic cretin )


..... Phil


Asked for an \"op amp.\"
Click to expand...

** You asked for a video amp with specified gain and phase performance.

You stated driving 75ohms was not essential - cos you could add a buffer to do that. You asked for $1.50 each and the uA733 is less in 100 off.

You are one pathetic, lying bullshititgn asshole.

FOAD.


...... Phil
 
On Tuesday, October 6, 2020 at 5:59:40 PM UTC-4, bitrex wrote:
On 10/6/2020 5:19 PM, Michael Terrell wrote:
On Tuesday, October 6, 2020 at 2:08:07 PM UTC-4, bitrex wrote:
On 10/6/2020 12:18 PM, Michael Terrell wrote:
On Tuesday, October 6, 2020 at 11:13:58 AM UTC-4, bitrex wrote:

Asked for an \"op amp.\" There are suitable op amps that can drive coax
and ones that can\'t. The uA733 isn\'t even an op amp.

Must be a slow day for you bro because you are reaching

Analog Devices make Op-Amps for HD TV that drive coax with over 350 MHz bandwidth. I have some Grass Valley and some Extron video DAs that use them. I can pull one to get the part numbers, if needed. I can\'t access my external drive with my design notes right now. I\'m still having electrical problems. That computer is on a circuit that was fried. I convert the video DAs to 50 ohm for 10MHz DAs

Yeah a list of any part #s would be nice, though AD products sometimes
tend to break the bank :)

I was pretty surprised this thinger is only $1 in quantity. I need to
multiplex several signals and drive a cable and it fits the bill:

https://www.mouser.com/ProductDetail/Analog-Devices/LT6559CUDPBF?qs=hVkxg5c3xu%2FSkXiqmdItxQ%3D%3D

300MHz bandwidth is probably overkill for standard def composite but
it\'s hard to argue with the price. Honestly lots of inexpensive op amps
have what it takes in theory for the bandwidth and output drive to do
the job for standard-def composite but the ones that do it well have low
differential gain and phase error

As a Broadcast engineer, I was thrilled when RCA introduced a first real video amplifier for NTSC video in 1988. It was flat to 5 MHz, and it could drive 75Ohm coax. All for $10 each, if you could even buy them. A Broadcast DA was over $1000, per channel, with four outputs. That was what Grass Valley started the company with, Video DAs. They eliminated having to loop everything on one output. You had seperate feeds for the transmitter, master monitor and two others to drive less critical loads. No one liked going off air to exchange equipment when a monitor died, in a long loop. They also made DA\'s for synce signals and Chroma.

One thing that doesn\'t seem easy to find at reasonable cost nowadays is
a synchronization/\"black burst\" signal-generator chip. That e.g. just
generates the NTSC composite timing pulses but no luminance or chroma so
you get a black raster.

The LM1881 is still made but the LM1882 looks to be gone. The \'1881 can
strip the video from a composite signal if you already have it but
doesn\'t look like it can generate the sync itself.

Renesas does make a cheap chip that can generate the frequencies you\'d
need for different standards from a clock by fractional PLL but you\'d
need some external logic to make a black burst:

https://www.mouser.com/datasheet/2/698/IDT__DST_20100514_21-1711558.pdf
Click to expand...

I have a Tektronix TSG170A NTSC Television Sync Generator.I bought it when NTSC died for broadcasting. I also have some Tektronix Waveform Monitors and Vector Scopes. I will try to get those IC numbers, later today. I think one of the Grass Valley rack mount systems is where I can get to it.
 
On 10/7/2020 5:28 AM, Michael Terrell wrote:
On Tuesday, October 6, 2020 at 5:59:40 PM UTC-4, bitrex wrote:
On 10/6/2020 5:19 PM, Michael Terrell wrote:
On Tuesday, October 6, 2020 at 2:08:07 PM UTC-4, bitrex wrote:
On 10/6/2020 12:18 PM, Michael Terrell wrote:
On Tuesday, October 6, 2020 at 11:13:58 AM UTC-4, bitrex wrote:

Asked for an \"op amp.\" There are suitable op amps that can drive coax
and ones that can\'t. The uA733 isn\'t even an op amp.

Must be a slow day for you bro because you are reaching

Analog Devices make Op-Amps for HD TV that drive coax with over 350 MHz bandwidth. I have some Grass Valley and some Extron video DAs that use them. I can pull one to get the part numbers, if needed. I can\'t access my external drive with my design notes right now. I\'m still having electrical problems. That computer is on a circuit that was fried. I convert the video DAs to 50 ohm for 10MHz DAs

Yeah a list of any part #s would be nice, though AD products sometimes
tend to break the bank :)

I was pretty surprised this thinger is only $1 in quantity. I need to
multiplex several signals and drive a cable and it fits the bill:

https://www.mouser.com/ProductDetail/Analog-Devices/LT6559CUDPBF?qs=hVkxg5c3xu%2FSkXiqmdItxQ%3D%3D

300MHz bandwidth is probably overkill for standard def composite but
it\'s hard to argue with the price. Honestly lots of inexpensive op amps
have what it takes in theory for the bandwidth and output drive to do
the job for standard-def composite but the ones that do it well have low
differential gain and phase error

As a Broadcast engineer, I was thrilled when RCA introduced a first real video amplifier for NTSC video in 1988. It was flat to 5 MHz, and it could drive 75Ohm coax. All for $10 each, if you could even buy them. A Broadcast DA was over $1000, per channel, with four outputs. That was what Grass Valley started the company with, Video DAs. They eliminated having to loop everything on one output. You had seperate feeds for the transmitter, master monitor and two others to drive less critical loads. No one liked going off air to exchange equipment when a monitor died, in a long loop. They also made DA\'s for synce signals and Chroma.

One thing that doesn\'t seem easy to find at reasonable cost nowadays is
a synchronization/\"black burst\" signal-generator chip. That e.g. just
generates the NTSC composite timing pulses but no luminance or chroma so
you get a black raster.

The LM1881 is still made but the LM1882 looks to be gone. The \'1881 can
strip the video from a composite signal if you already have it but
doesn\'t look like it can generate the sync itself.

Renesas does make a cheap chip that can generate the frequencies you\'d
need for different standards from a clock by fractional PLL but you\'d
need some external logic to make a black burst:

https://www.mouser.com/datasheet/2/698/IDT__DST_20100514_21-1711558.pdf


I have a Tektronix TSG170A NTSC Television Sync Generator.I bought it when NTSC died for broadcasting. I also have some Tektronix Waveform Monitors and Vector Scopes. I will try to get those IC numbers, later today. I think one of the Grass Valley rack mount systems is where I can get to it.
Click to expand...

The TSG170A looks relatively modern and expensive enough that it might
be synthesizing all the signals from a microprocesor....

\"The Tektronix TSG170A NTSC Television Generator offers you the test
signals you need plus the advantages of master- and genlock-sync
capability. It provides true 10-bit digital signal accuracy with a full
complement of test signals and a stable master sync generator.\"

Fast 10 bit DACs are definitely cheaper than they used to be, too
 
On Wednesday, October 7, 2020 at 8:35:54 AM UTC-4, bitrex wrote:
The TSG170A looks relatively modern and expensive enough that it might
be synthesizing all the signals from a microprocessor....

\"The Tektronix TSG170A NTSC Television Generator offers you the test
signals you need plus the advantages of master- and genlock-sync
capability. It provides true 10-bit digital signal accuracy with a full
complement of test signals and a stable master sync generator.\"

Fast 10 bit DACs are definitely cheaper than they used to be, too
Click to expand...

It was $41 on Ebay. The first Sync Generator that I used was RTL based, and built by Grass Valley in the early \'70s. It was monochrome only, but I still managed to transmit a slide with color. The station got it, when the received their Distribuition Amplifiers. They were given a new transmitter by AFRTS, and the DAs eliminated the need to change video cables when switching transmitters. The Sync generator was a dual system with genlock and automatic fall over upon failure.
 
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