Showing posts with label wireless tv. Show all posts
Showing posts with label wireless tv. Show all posts

Thursday, September 15, 2016

Output power of an analog wireless TV sender

Output power of an analog wireless TV sender

The output power of a wireless TV sender( or wireless av sender ) is the electric power applied to antenna system. There are two definitions: nominal (or peak) and thermal. Analogue television systems put about 70% to 90% of the transmitters power into the sync pulses. The remainder of the av transmitter's power goes into transmitting the video's higher frequencies and the FM audio carrier. Digital television modulation systems are about 30% more efficient than analogue modulation systems overall.


Analogue vs digital
Analogue

    The large amount of energy that Sync Pulses use is largely independent of the measurement system and efficiency of the analogue wireless TV sender (as most analogue transmitters have on average 75% efficiency).
    The transmission of FM audio (including Stereo subcarriers) is only overall the 3rd largest consumer of wireless TV sender power.
    Power consumption (most to least) : Sync Pulses, High Frequency Video, FM Audio, Vestigial AM

Digital

    DVB like transmission systems, with their groups of mathematically related carriers are not quite as energy efficient as 8VSB systems
    8VSB transmission systems only provide a limited "Forced DC" signal (that consumes about 7% of the transmitters energy) that under multipath conditions can be lost causing a signal lock loss event

Power defined in terms of voltage
The average power for a sinusoidal drive is




For a system where the voltage and the current are in phase, the output power can be given as




In this equation "R" is the resistance and "e(t)"  is the output voltage

Nominal power of a wireless TV sender
Nominal power of a wireless TV sender is given as the power during the sync interval. (For the sake of simplicity aural power is omitted) Since, the voltage during the sync interval is a fixed value,






where "E" is the rms value of the output voltage.

To measure the nominal output power, measuring devices with time constants much greater than the line time are used. So the measuring equipment's measure only the highest level (sync pulse) of a line waveform which is 100%.

This power level is the commercial power of the transmitter.

Thermal power
In analogue TV broadcasting, the video signal modulates a carrier by a kind of amplitude modulation (VSB modulation or C3F). The modulation polarity is negative. That means that the higher the level of the video signal the lower the power of the RF signal.

The lowest possible modulating signal during the synchrone interval yields 100% of the carrier. (The nominal power of the transmitter.) The blanking level (300 mV) yields 73% (in an ideally linear transmitter). Usually the figure 75% is found to be acceptable. The highest modulating signal at white (1000 mV) yields only 10% of the carrier. (so called residual carrier). Sometimes 12.5% is used as the residual carrier so the output power applied to the antenna system is considerably lower than the nominal power.

The thermal power which can be measured by a microwave power meter depends on the program content as well as the residual carrier and sync depths.

Ratio of thermal power to nominal power
Since the program content is variable, the thermal power varies during the transmission. However, for testing purposes a standard line waveform can be applied to the transmitter.

Usually line waveforms corresponding to 350 mV or 300 mV black image (and without field sync) are applied to the input of the transmitter.

For System B, the duration of the black level 300 mV (together with the front and back porches), is 59.3 μs and it corresponds to 73% of maximum voltage level. The duration of the sync pulse is 4.7 μs. The total duration of the line is 64 μs.




So the maximum thermal power applied to the antenna system is 57% of the nominal power, even in the black scene. In normal program content this ratio may be around 25% or less.


recommend reading:
Why We Choose Wireless Audio-Video Transmitter and Receiver?
PAKITE PAT-220 AV Sender Reviews
Five reasons to choose PAKITE
Wireless digital/analog TV sender | PAKITE
New goods: PAKITE HDMI jack Wireless A/V Sender
What is HDMI Wireless A/V Sender? | PAKITE

Tuesday, September 13, 2016

Who needs the Wireless TV Transmitter?

Who needs the audio video Wireless TV Transmitter?

TV audio video transmitter


The wireless av transmitter mentioned here are for the wireless transmission of video and audio signals from STB/ DVD /IPTV to a TV. There are three main uses for a wireless product:

*If your sources are in a different part of the room than the TV, you can send the signal wirelessly instead of running long cables across the floor (or under the floor, or along the baseboards, etc). This is an especially common problem with projectors.

*If you want to mount your TV on the wall, you need to run power and cables. With wireless, you only need to run power to the TV. The signal from your sources gets sent wirelessly to the small receiver box. In the case of the Pakite wireless tv transmitter, the TV itself can often power this wireless receiver.

*If you want to have your sources and TV in two different rooms. Again, the Pakite wireless tv signal transmitter is a good pick here because it is able to transmit through walls , so you can have a TV in the same room as the sources, and a second TV connected wirelessly to the same sources.

*If you have equipment specifically with HDMI outputs (Blu-ray players, cable boxes, Apple TV and Roku streamers, etc.). This is not for products like Chromecast, or any of the Miracast or WiDi products (which wirelessly stream content from tablets, phones, or laptops). Those are a different category, these are replacements for HDMI cables. HDMI interface devices need a hdmi wireless transmitter to transmit audio and hd video signal.


Keep in mind though, there is a cost to the convenience. Wireless is always going be more temperamental than wired, taking a few moments to sync up (connect) and potentially/occasionally dropping out.


How do you connect wireless Audio Video Transmission Kit?

How do you connect wireless AV Transmission Kit?

A wireless AV (audio / video) transmission kit functions in much the same way as a wireless home network, radio frequency waves traveling between the transmitter and a receiver. User just need to Connect the wireless AV transmission kit between a STB and a TV, no need to adjustments wireless signal. All the necessary parts are included in the package, with the exception of AV cables and IR cable.

  • 3 pcs Mini - jack to RCA Jack Cable ;
  • 1 pcs IR Cable ;
  • 2 pcs 5V/1A Power adapter ;
  • 1 pcs User Manual;


Correct connect your wireless audio video transmission kit by the following steps:
1. Place wireless av transmitter with Set-Top Box(STB). Plug one end of the RCA AV cable into the AV output of the STB, Plug the power adapter into a socket for power.
2. Place wireless av receiver with monitor or TV, Plug one end of the RCA AV cable into the AV input of the TV, Plug the power adapter into a socket for power.
3. Place the wireless av receiver next to the TV. Plug one end of the RCA AV cable into the AV input of the TV, Plug the power adapter into a socket for power.
4. Plug RCA plugs on the other end of the av cable into the av outputs on the back of the STB, Plug RCA plugs on the other end of the av cable into the av inputs on the back of the TV.
5. Turn on the TV with the remote. Press Menu. Select "Video input" and select the av input to which the av cable is connected.

It’s complicated by description, but if you would options by yourself or review by video, that will be much simple. You can leave message at www.pakite.net , we will contact with you as soon as possible.


PAKITE Wireless Network set-top box sharing Device

PAKITE Wireless Network set-top box sharing Device: Wireless TV Sender




Now everyone watch digital TV programs, but are different from analog era, a set-top box(cable box) can only match a TV. If you have two TV set at home, then you have to buy two set-top boxes. TV set-top box is not installed will become decoration. If re-install another set-top box, in addition to the purchase cost of set-top box, the set-top box will have to pay a monthly fee. Most family will choose the set-top box installed in the sitting room, so that when we need in the other room to watch digital TV (share tv signal wirelessly) will encounter problems. In fact, we do not usually watch TV in a fixed place, more often, we in the living room during the day and watch the evening want to continue to watch in the bedroom, so if there no cable boxes in the bedroom, it cannot continue to watch digital TV programs. Not only the digital set-top box will encounter this problem, when using DVD player, satellite TV receiver and other A/V device have the same trouble.
Digital set-top boxes generally divided broadcast, basic, enhanced (IPTV demand type). Which enhanced STB is powerful, it not only brings us a rich live television programs, also provide vast amounts of TV on demand, video playback. The event, news, review you missed can watch again. However, enhanced set-top box price and the monthly cost is relatively high, with the set-top box on each TV, this is absolutely typical waste of resources.


A set-top box can only to a TV set, thought of lying on the bed to watch TV in the room, but the room do not have the line to connect, set-top boxes can not be detached and moved to the room. Install a set-top box and have to pay rent, but also not commonly used. Pakite audio video signal stb wireless sharing device will help you! It is named wireless av sender ( It includes an av transmitter and a receiver ). Implementation can watch digital TV in the room, if you want to change the channel, do not need to be running around, you can change channels in the room directly! The range of available machine: digital set-top boxes, satellite set-top boxes, DVD player, AV audio-visual equipment such as DV machine!


Friday, September 9, 2016

How Wireless audio video TV Transmitter Work



How Wireless TV AV Sender Work


Let’s talk wireless av sender connection by picture. And step by step.
wireless av sender and receiver
Transmitter:
How does wireless tv transmitter receiver work? It's simple really; let's use PAT-220 av sender as an example. The Transmitter connects to your STB by AV cables. Your STB signal is then wirelessly transmitted, through walls and ceilings, to the Receiver.

Receiver:
The Receiver picks up the STB signal sent from the Transmitter and displays it on your TV in another room. you can still use your STB remote to control your STB box using the built-in IR Remote Control.


Connection:
Transmitter Connection:
Just place the av transmitter above the STB, connect av transmitter with STB by AV cable in the right way, as the picture show.
Transmitter connection
Receiver Connection:
Place the receiver besides the tv, and connect the tv by av cable in the right way,as the picture show.


Receiver connectiong


IR Cable Connection:
Connect the IR Cable with Transmitter, and stick the infrared receiving at the infrared of STB receiver, like the following picture.
IR cable connection


When you finish the above the step, get the power, you can watch program at different rooms.

But one more thing need to pay attention is: all of receiver were getting the same signal from transmitter, so all of the receiver was display the same program at different monitor.

Wireless TV AV Sender



Thursday, September 8, 2016

Why We Choose Wireless Audio-Video Transmitter and Receiver?



  Someone may ask this question: I have cable service in my living room only. but I want to watch TV in my bedroom and don't want to run a cable. Is there a device that will let me remotely have TV in my bedroom without running a cable?
 Yes, of course. It's called wireless AV Sender( you can call it wireless tv sender too ), which can realize the audio video signal sharing in different rooms for family entertainment. The wireless av sender consists of a transmitter and a receiver. On a small scale, it works the same way as a TV antenna only instead of a local broadcast station sending a signal out to anyone who has an antenna, the TV in your living room will be the sender of the signal for the receiver in your bedroom .
   PAKITE Wireless AV transmitter and receiver is well known and professional. We have kinds of Audio Video receiver and transmitter for different demands. It adopting advanced 2.4GHz/5.8GHz wireless transmission schemes and having advantages of long distance transmission, strong anti-interference and high mobility. By means of radio waves, it can transmit the signal from DVD player, DVR, CCTV camera, IPTV, Satellite receiver, Digital TV Set Top Box or any other A/V devices at transmitter end to TV sets in different room at receiver end. Moreover, it can support the IR remote control at the av receiver end to realize the function of wireless control of devices from another place. So that you can enjoy freely wireless HD AV sharing data and Hi-Fi audio and video effect.
   My advice is to have the transmitter and receiver in as open a space as possible to avoid any interference.
   Besides, if your family or neighbor were installed 2.4GHz equipment such as Wireless WIFI or cordless telephone, please choose 5.8G series AV transmitter and receiver. 

  Choosing wireless audio video transmitter and receiver, It enables you to satisfy the transmission of A/V device and digital TV STB device. It enables you to easily realize wireless sharing of SD AV data and enjoy untrammeled hi-fi audio and visual effects. 

Sunday, September 4, 2016

Two TV sharing one set-top box in my house

Two TV sharing one set-top box in my house, the sharing device is wireless av sender
Two TV sharing one set-top box
By the picture, do you know what's the device to make Two TV sharing one set-top box/cable box come true? It named wireless av sender, and it contain a transmitter and receiver. More useful guides, please visit CNBgear tech site.

HDMI av sender, HDMI TV to TV Wireless
HDMI av sender

By the gif picture, it's a newborn av sender with hdmi jack in the whole world, PAKITE brand, and the hdmi av sender can send the TV signal to another room's TV by wireless, it fits for your TV, cable box(set top box), DVD and other device which with hdmi port.

The PAKITE hdmi av sender transmission range is 300m without any holdback, output resolution is 720x576p, and the price is much cheaper than a full HD 1080p hdmi av sender. So, the PAKITE wireless hdmi transmitter will be very popular in the whole world family, isn't it? The more details about this new baby will be on pakite's website www.pakite.net, a new and huge business opportunity is waiting for you!


recommend reading: