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Participant deepakb
Participant
1,536 Views
Registered: ‎08-07-2013

Reference clock requirement for SDI TX and RX

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Hello,

 

We are doing some custom board with 1 SDI input and 3 SDI output. I am using SDI TX and RX subsystems for the same.

I refereed the SDI pass-through design for ZCU106 for the same.

 

My question is whether I use a single reference clock of frequency 148.5Mhz,  for all SDI interfaces (1 SDI RX and 3 SDI TX). I was able to do this configuration in UHD SDI GT IP as shown in attached snapshot.

I hope single clock with 148.5Mhz, should be sufficient for all SDI interfaces. Please confirm.

 

Thanks in advance,

DPK

SDI_GT.png
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1 Solution

Accepted Solutions
Explorer
Explorer
1,721 Views
Registered: ‎07-18-2011

Re: Reference clock requirement for SDI TX and RX

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SDI clock rates are as follows:

 

SD-SDI : 270MHz  (480i/576i, with a 27MHz clock rate)

HD-SDI:  1.485GHz  (720p50/60, 1080i50/60)  or 1.485GHz/1.001  (720p59.94, 1080i59.94)

3G-SDI:  2.97GHz  (1080p50/60)  or 2.97GHz/1.001  (1080p59.94)

 

The Xilinx SDI core can support all five of those standards with only two reference clocks, 148.5MHz and 148.5/1.001 MHz.

 

If you only need to support 1080p60, 1080p50, 720p60, and 720p50, you can use a single 148.5MHz ref clock, as they all use the 148.5MHz ref clock.

 

If, however, you need to support 1080p59.94 or 720p59.94, you will need the 148.5/1.001 ref clock.

 

 

 

 

 

 

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4 Replies
Explorer
Explorer
1,483 Views
Registered: ‎07-18-2011

Re: Reference clock requirement for SDI TX and RX

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If you want to do all the resolutions for both NTSC and PAL, 50/60Hz and 59.94Hz, for example, you need two reference clocks, a 148.5 MHz and a 148.5/1.001 MHz.

 

If you only need to do one resolution at a time for both in and out, you can use a single programmable clock reference, such as the Si544 series from Silicon Labs, which will allow you to change the reference clock frequency from 148.5MHz to 148.5/1.001 MHz via I2C.

 

 

 

 

Participant deepakb
Participant
1,462 Views
Registered: ‎08-07-2013

Re: Reference clock requirement for SDI TX and RX

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Hello Reaiken, 

 

Thank you for your response.

In my case, we need to support 720p (HD) and 1080p(Full HD) resolutions for input (SDI RX) and output (SDI TX) is fixed to 1080p(Full HD).

In this also I hope we can use same reference clock of 148.5Mhz for both TX and RX.

It will be very helpful if you confirm the same.

 

Thanks and Regards,

DPK

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Explorer
Explorer
1,722 Views
Registered: ‎07-18-2011

Re: Reference clock requirement for SDI TX and RX

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SDI clock rates are as follows:

 

SD-SDI : 270MHz  (480i/576i, with a 27MHz clock rate)

HD-SDI:  1.485GHz  (720p50/60, 1080i50/60)  or 1.485GHz/1.001  (720p59.94, 1080i59.94)

3G-SDI:  2.97GHz  (1080p50/60)  or 2.97GHz/1.001  (1080p59.94)

 

The Xilinx SDI core can support all five of those standards with only two reference clocks, 148.5MHz and 148.5/1.001 MHz.

 

If you only need to support 1080p60, 1080p50, 720p60, and 720p50, you can use a single 148.5MHz ref clock, as they all use the 148.5MHz ref clock.

 

If, however, you need to support 1080p59.94 or 720p59.94, you will need the 148.5/1.001 ref clock.

 

 

 

 

 

 

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Participant deepakb
Participant
1,398 Views
Registered: ‎08-07-2013

Re: Reference clock requirement for SDI TX and RX

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Hello Reaiken,

 

Thank you so much for the answer and support.

 

 

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