Home Blog Blogs What is an HDMI modulator?

What is an HDMI modulator?

What is an HDMI modulator?

What is an HDMI modulator?

Table of Contents

1. What is an HDMI modulator? what is hd modulator?

1.1 What does an HDMI modulator do? What is a TV modulator used for?

1.2. What is the difference between modulation and encoding? 

1.3. What is the resolution of the RF modulator?

2. How to use an HDMI rf modulator? 

2.1 How to install an HDMI modulator? 

2.2.How do I connect my HDMI modulator? 

2.3.How do I setup my HDMI modulator? 

3. How to buy an HDMI rf modulator?

3.1 Where can I buy a hd rf modulator? 

3.2. Different from HDMI to analog converter/adapter 

3.3 What type of HDMI modulator do I need? 

1. What is an HDMI Modulator? What is HD Modulator?

HDMI Modulator is a professional broadcast level highly integrated digital front-end device that supports HDMI input, and RF signal output and integrates encoding and modulation functions.


1-channel HDMI Modulator


8 channels HDMI Modulator

It supports 4/8/12/16/20/24 HDMI input for option, 1000M IP output, 4(8)RF output(ATSC/ISDBT/DVB-C/DVB-T), 5 MPTS output, and SPTS output. 

It also supports QR codes, LOGO, and closed caption insertion.


1.1 What does an HDMI Modulator do? What is a TV modulator used for? What does an HD modulator do?

Because it integrates two functions of encoding and modulation, it is more cost-effective than purchasing a separate encoder or modulator with only one function. 

Ideal for hotels, or analog switch to digital cable TV systems. And the model with 1 HDMI input is also widely used for monitoring and entertainment in the home.

1.2 What is the difference between modulation and encoding?

modulation vs encoding

The encoder is to process audio and video signals into digital TS streams

While the modulator converts the digital signal TS stream into RF signal.

Their functions are completely different.

The encoder input supports high-definition HDMI, HD-SDI, or analog AV audio and video signals, and the output port is IP or ASI cable. The output digital signal TS can be used as an IPTV signal source or connected to a modulator.

While the input interface of the modulator is ASI/IP, and the output interface is RF, which is distributed to an unlimited number of the terminal set-top box or television over almost any distance. 

1.3 What is the resolution of the RF modulator?

Support Ultra HD 4K:3840×2160_60P,3840×2160_60P, 3840×2160_50P,3840×2160_30P,  


Support HD 1080:1920×1080_60P,1920×1080_50P, 1920×1080_30P ,1920×1080_25P 1920×1080_24P,

Support HD  720:1280*720_60p, 1280*720_50P,720*480_60i, 720*576_50i

Compared to SD AV modulator Input:720×576i (PAL-B, D, G, H, I), 720×480i (NTSC-M, J)

Output: 544×576 / 544×480(PAL/NTSC)

             480×576 / 480×480(PAL/NTSC)

             352×576 / 352×480(PAL/NTSC)

             352×288 / 352×240(PAL/NTSC)

             176×144 / 176×112(PAL/NTSC)

2. How to use HDMI rf modulator?

 2.1 How to install an HDMI Modulator?


When you get an HDMI modulator, please read the user manual carefully.

Here is a manual for your reference:

user manual of qam moduator

2.2 How do I connect my HDMI modulator?

For one channel:



  • Step1:Mount and tighten the screws and plugs to secure the unit to the wall. Left 10 cm of free space around each unit.

  • Step2:Connect the signal input in the respective connectors. The signal source can be from a surveillance monitor, DVD, set-top box, CCTV and etc.

  • Step3:Optionally, connect the loop-through RF input coaxial cable. 

  • Step4:Connect your cable to RF output to STB/TV.

  • Step 5: Power supply connection: a) Connect the earth cable; b) Connect the power plug to the unit mains connector; c) Connect the power plug to the mains socket.

For multi-channel:


 2.3 How do I setup my HDMI modulator?

Enter encoding parameters interface:

  • Video Parameters: You can enter the items respectively to set the input interface and view the video status. 

adjust values of the resolution, bit rate, brightness, contrast saturation...

  • Audio Bit rate: Select audio bit rate among 64, 96, 128, 192, 256, 320, 384 kbps.

  • Audio Format: Select audio format among MPEG2, MPEG2-AAC and MPEG4-AAC.

  • Program Information: edit program name, program number, and PIDs of PMT, PCR, Video, and Audio, and edit LCN

Enter modulation parameters interface:

Here this takes DVB-T modulation as an example. 

  • Bandwidth: Choose between 6M, 7M and 8M.

  • Constellation: DVB-T modulator contains 3 constellation modes – 64 QAM, QPSK and 16 QAM. 

  • FFT (Transmission Mode): 2K, 8K (8K Optional) 

  • Guard Interval: Select among 1/32, 1/16, 1/8 and 1/4.

  • Code Rate: It refers to the FEC-Forward Error Correction rate. It contains 1/2, 2/3, 3/4, 5/6 and 7/8.

NOTE: The different combinations of bandwidth, constellation, guard interval and code rate (FEC) will form a different output code rate. Please refer to Table 1, Table 2, and Table 3 in this article

  • RF Frequency: Adjust it at the range of 30 to 999 MHz. Set it according to your regional situation or inquire about your local services.

  • RF Level: Adjust it at the range of -16~ -36dBm.

3. How to buy an HDMI RF Modulator?

 3.1.Where can I buy a hd rf modulator

Find a professional digital head-end supplier, which can supply longer warranty and technical support time, including installation and use.

3.2Different with HDMI to analog converter/adapter

When you have some questions like this "How do you connect HDMI to coaxial cable? Can you convert HDMI to coax?"

We often find this "HDMI to RF"


HDMI to Coaxial RF Converter/Adapter

This is for old TVs, which output analog signals after HDMI high-definition signals are collected and simply processed.

If you need to connect high-definition signals to an old TV, you can just use an HDMI to AV cable, like this


The resolution you know is very poor.

 3.3 What type of HDMI modulator do I need?

Input: 1channel, 4channels, 8 channels, 16channels and 24channels

Chassis: Portable or engineering

Input interface: HDMI, HD-SDI, AV, DVB-S/S2 tuner 

Choosing the one you need is the best