LMH1983: LMH1983

Shlomi Itzhakov

Prodigy 20 points

Part Number: LMH1983
Other Parts Discussed in Thread: LMH1982,

I want to use the part in GENLOCK mode .

My system provides H sync and V sync only to my circuit .

Can I ignore the Fin signal (as LMH1982) and use only the H V sync?

My inputs to the FPGA are 3 HD SDI in and 3 HD SDI out signals .

over 2 years ago

0 Noel Fung over 2 years ago

TI__Guru* 85360 points

Hi Shiomi,

Genlock only needs Hsync signal. However, auto-format detection and TOF generation will need all HVF signals.

0 Shlomi Itzhakov over 2 years ago in reply to Noel Fung

Prodigy 20 points

Hi Noel

the system send to my product Hsync and Vsync.

My HDSDI signals comes from 3 cameras .

For TOF can I use only the Vsync? ( I known the format form the CAMs I don't need to auto-format detection )

What are the consequences for not using the Fin pin?

shlomi

0 Noel Fung over 2 years ago in reply to Shlomi Itzhakov

TI__Guru* 85360 points

Hi Shlomi,

Yes, that is possible but TOF1 alignment is not possible as there is no F signal.

0 Shlomi Itzhakov over 2 years ago in reply to Noel Fung

Prodigy 20 points

Hi Noel,

What is the reason for Hin? ( Hsync)

What this signal is needed for?

shlomi

0 Noel Fung over 2 years ago in reply to Shlomi Itzhakov

TI__Guru* 85360 points

Hi Shlomi,

Hsync is the reference clock of PLL1, you must have this signal in Genlock mode, otherwise, you could only be in free running mode.

0 Shlomi Itzhakov over 2 years ago in reply to Noel Fung

Prodigy 20 points

Hi Noel,

Sorry , I meant Vsync

Shlomi

0 Noel Fung over 2 years ago in reply to Shlomi Itzhakov

TI__Guru* 85360 points

Hi Shlomi,

Vsync is also used for auto-format detection.

The LMH1983 uses a two dimensional look up table to determine format - it looks at V and F to determine if it is looking at an interlaced or progressive format, and it then measures Hin frequency - using the combination of H frequency and interlace/progressive, it determines format. There are some pairs of formats interlaced/progressive which share the same or very similar Hin rates, so you need to look at both to determine format.

0 Shlomi Itzhakov over 2 years ago in reply to Noel Fung

Prodigy 20 points

Hi Noel,

Thank you for your patience.

There is a similar part LMH1982 that receive only H sync and V sync . ( Can't use LMH1982 because of Temperature range, I need -40 to 85 )

Can I operate LMH1983 at same mode?

Shlomi

0 Noel Fung over 2 years ago in reply to Shlomi Itzhakov

TI__Guru* 85360 points

Hi Shlomi,

Without F, both device do the same thing except that LMH1983 can support audio and its performance is better than LMH1982.

0 Shlomi Itzhakov over 2 years ago in reply to Noel Fung

Prodigy 20 points

Hi Noel,

To summarized it .

I apply Vin and Hin to LMH1983 and I get GENLOCK Freq and TOF like as LMH1982.

Am I right.

Shlomi

+1 Noel Fung over 2 years ago in reply to Shlomi Itzhakov

TI__Guru* 85360 points

correct.

Clock & timing

Clock & timing forum

LMH1983: LMH1983