This document discusses bandwidth requirements for transmitting high-resolution signals and the effect of modulation schemes on bandwidth. It explains that higher resolution formats like 4K and 8K video require more bandwidth than SD or HD. Data compression can reduce the bandwidth needed by compressing the data. Using more advanced modulation schemes like QAM that encode more bits per symbol can also reduce bandwidth needs but introduces more complexity. The roll-off factor α of a digital filter can be optimized to reduce bandwidth requirements, but lowering it too much can cause interference. Higher values of α increase the occupied bandwidth. The document provides tables comparing the bandwidth needs of different resolutions and modulation schemes.

1. Internal - General Use
Bandwidth estimation required by
DAC to transmit a high-resolution
signal and Effect of Modulation
schemes on transmit bandwidth.
Shiv Dutt
Architect, Wipro Limited

2. Internal - General Use
Data Bandwidth Requirement
To Collect information through any one required bandwidth
• Video and images.
• Voice transmission or receiving
• broadcasting on YouTube, TV and OTT channels.
• Browsing on internet
Whenever Analog is converted int binary it required data bandwidth of your device.

3. Internal - General Use
More data more bandwidth
High quality of signal required more bandwidth as telecom industry
promising to serve such quality signal to their user. As you know High
resolution high signal quality so some signal standards are following
• Standard Definition | 480P
• High Definition | 720p
• Full HD | 1080p
• Quad HD | 2k
• Ultra HD | 4k
• Full Ultra HD | 8k
As peoples are buying Ultra HD TV 4k now these days to get best movie quality but it
depends on transmission also.

4. Internal - General Use
Pixels required in resolution
Technology Resolution Horizontal Vertical Pixels
Standard Definition 480p 640 480 3,07,200
High Definition 720p 1280 720 9,21,600
Full HD 1080p 1920 1080 20,73,600
Quad HD 2k 2560 1440 36,86,400
Ultra HD 4k 3840 2160 82,94,400
Full Ultra HD 8k 7680 4320 3,31,77,600

5. Internal - General Use
Techniques to reduce data size
• Data Compression
There are two type of data compression technique; one is lossy and other is
lossless. Lossless data compression mostly used as it facilitates data compression
using encoding method without degrading quality.
• Optimizing α (alpha) roll of factor of digital filter
This is another method by which data can be compressed further by optimizing
alpha of digital filter but there is a limit for selecting lower value of it otherwise
inter symbol interference occurs.

6. Internal - General Use
Compressed data rate
It is required to reduce desired bandwidth without degrading quality. Last table can be
used to calculate compressed data rate with following relations.
As We know
Data rate= total pixels used x Frame rate x no. of bits to encode
Assuming video transmission rate using in broadcasting
Frame rate =24fps
Device bits=24
Compressed data rate= Actual data rate/ Compression ratio
Assuming Compression ratio=100

7. Internal - General Use
Compressed data rate cont.
Technology Resolution Horizontal Vertical Pixels
Actual Data
Rate (Mbps)
Compressed data
rate(Mbps)
Compression
ratio=100
Standard
Definition 480p 640 480 3,07,200 221 2.21
High Definition 720p 1280 720 9,21,600 664 6.64
Full HD 1080p 1920 1080 20,73,600 1493 14.93
Quad HD 2k 2560 1440 36,86,400 2654 26.54
Ultra HD 4k 3840 2160 82,94,400 5972 59.72
Full Ultra HD 8k 7680 4320 3,31,77,600 23888 238.88

8. Internal - General Use
Actual data vs Compressed data

9. Internal - General Use
Optimizing α (alpha) of digital filter
As we know to define bit rate of any signal is;
• Bit rate= Symbol Rate x No. of bits for each symbol
• Symbol rate = Bit rate / No .of bits for each symbol
Spectrum signal Bandwidth can be given below
• Occupied signal bandwidth =Symbol rate x (1 + α)
α is called roll off factor or bandwidth factor. It describes the shape of Cosine digital
filter. Higher the value of α increases the bandwidth as Described in next Table.

10. Internal - General Use
Modulation bit per symbol
As we know Higher
modulation lesser the
bandwidth requirement as
no. of bits per symbol
higher that is called bit
rate. Although there is
other complexity with
higher modulations, but it
helps to use bandwidth
efficiently.

11. Internal - General Use
Occupied Bandwidth
Technology Resolution
Compressed
data
rate(Mbps)
Compression
ratio=200
QPSK
2 bit
signal
(MHz)
16QAM
4bit
signal
(MHz)
64QAM
6bit signal
(MHz)
256QAM
8bit
signal
(MHz)
1024QAM
10 bit signal
(MHz)
Standard
Definition 480p 2.21 1.382 0.432 0.090 0.014 0.002
High Definition 720p 6.64 4.147 1.296 0.270 0.042 0.005
Full HD 1080p 14.93 9.331 2.916 0.608 0.095 0.012
Quad HD 2k 26.54 16.589 5.184 1.080 0.169 0.021
Ultra HD 4k 59.72 37.325 11.664 2.430 0.380 0.047
Full Ultra HD 8k 238.88 149.299 46.656 9.720 1.519 0.190
Occupied bandwidth calculations extending previous table for different
Modulation schemes when α=0.25. If DAC bandwidth is 56Mhz then QPSK
will restrict for 8k resolution.

12. Internal - General Use
Resolution technologies versus Signal Bandwidth
0.001
0.010
0.100
1.000
10.000
100.000
1000.000
480p 720p 1080p 2k 4k 8k
SIGNAL
BANDWIDTH
(MHZ)----->
RESOLUTION TECHNOLOGIES ------>
Resolution technologies versus Signal Bandwidth
Higher Modulation occupies lesser Bandwidth
QPSK 16QAM 64QAM 256QAM 1024QAM

13. Internal - General Use
Bandwidth optimization for α value
Technology Resolution
Compressed
data
rate(MBps)
Compressio
n ratio=200
QPSK 2 bit
signal (MHz)
@α=0.25
QPSK 2 bit
signal
(MHz)
@𝛼=0.5
QPSK 2 bit
signal
(MHz)
@α=0.75
QPSK 2 bit
signal (MHz)
@α=1.0
Standard
Definition 480p 2.21 1.38 1.66 1.94 2.21
High Definition 720p 6.64 4.15 4.98 5.81 6.64
Full HD 1080p 14.93 9.33 11.20 13.06 14.93
Quad HD 2k 26.54 16.59 19.91 23.22 26.54
Ultra HD 4k 59.72 37.32 44.79 52.25 59.72
Full Ultra HD 8k 238.88 149.30 179.16 209.02 238.88

14. Internal - General Use
Bandwidth variations with α value

15. Internal - General Use
Conclusion
• Data compression depends on compression ratio and this helps to
reduce data drastically without degrading signal quality as per lossless
data compression technique.
• Higher Modulation scheme having higher QAM order occupies lesser
bandwidth but may be more susceptible to noise so implementation
is challenging.
• Roll of factor α lower value is helpful to reduce required bandwidth
but limitation is there and more optimization required to avoid
interference.

16. Internal - General Use
Reference
• [1] https://community.silabs.com/s/article/calculation-of-the-occupied-bandwidth-for-digital-frequency-
modulation?language=en_US
• [2]https://www.sqimway.com/modulation.php
• [3] Application Note AN-922, Digital Pulse-Shaping Filter Basics
• [4] https://www.analog.com/en/analog-dialogue/articles/high-definition-low-delay-sdr-based-video-
transmission-in-uav-applications.html
• [5]https://rfmw.em.keysight.com/wireless/helpfiles/89600b/webhelp/Subsystems/digdemod/content/dlg_d
igdemod_fltr_alphabt.html

17. Internal - General Use
Thankyou