FAQs

Encoding is the process used to transform information from one format to another.

Video Encoding is generally referred to as a process that transforms an original analog, or “baseband” video source (e.g., a video camera), into a digitized, or encoded form that is acceptable for storage or transmission over a network.

The digitization process in video encoding is referred to as compression because the amount of information that remains after the encoding occurs is far less than the original source.

Popular encoding output formats used by service providers are MPEG-2, MPEG-4, H.264, or H.265.

Encoding establishes a transmission or playback speed called a bitrate, which represents the playback speed and/or the transmission bandwidth needed to send the video to another location.

Encoders use a process called “sampling” and “digitization” to convert or compress the original analog video signals into the new digital format. Over brief periods of time, an encoder takes a snapshot of an uncompressed original video signal  (input source) and processes it into a compressed digitized representation of the original information (output). Sampling and digitization usually occur about 30 or 60 times per second. The compressed output can be stored as a digital file for later playback and viewing or transmitted over a network to be viewed or saved.

Digitally encoded video and its related audio content are collectively referred to as an “elemental video” that when stored in a file can be played back by a video player.

To send the video over a network to a remote receiver for playback, the video must be “encapsulated”, or packaged into small chunks that fit into network packets. The most popular transmission encapsulation format is a MPEG Program Stream.

There are two popular types of programs streams, a Single Program Transport Stream (SPTS) that packages one video and its related audio, or a Multi-Program Transport Stream (MPTS) that can contain multiple video and their related audios. Video can be transmitted over an IP network as “Unicast” or “Multicast” streams.

Transcoding is the process of converting a previously encoded video into a different format from the originally digitally encoded format. MPEG-2 to H.264 is one form of transcoding. Transcoding can also be from one medium to another, such as 8-VSB (digital off-air) to QAM (digital CATV) or IP.

There may be many reasons for performing video transcoding. Some video compression formats are less efficient in terms of the resulting file size or bandwidth they use during transmission. Transcoding less efficient formats into more efficient ones save storage resources and/or transmission bandwidth. The most popular reasons are to reduce transmission bandwidth for broadcast or cable television, to reduce storage space for on-demand content, or to change from a format that is not viewable on the desired device.

Transcoders read the digital information of an encoded file and convert it to an analog format, or “baseband video”. It then uses the same sampling and digitizing process that an encoder uses to create a new digital representation in a different video format. Popular transformations are to convert MPEG-2 video into MPEG-4, H.264, or H.265 formats. Transcoding may introduce degradation of the prior digital signal because of the second sampling that occurs, but can still produce an acceptable video experience.

Transrating is the process of changing the bitrate of a previously encoded video source, but not the encoding format. This is intended to specifically reduce the bandwidth required for transmission, but will also have the side effect of reducing storage requirements for the recorded content. Unfortunately, the process still requires decoding the video and recoding it using the same video format but at a lower bitrate, so Transrating can degrade video quality. It is always best to transcode the original source to the correct bitrate in the first place.

Multiplexing, or muxing, generally refers to the collection of multiple video sources and their related audio and packaging them together into a Transport Stream to be stored and/or transmitted over a network as one identifiable service flow (i.e., using one file or one IP network address).

Demultiplexing or demuxing separates the video programs and their related audios that were previously combined into a Multi-Program Transport Stream (MPTS), and either stores them as separate SPTS transport stream files or Elementary Stream files, or creates new Single Program Transport Streams with their associated audios.

Fiber Transceivers are devices that can send and receive information either unidirectionally or bi-directionally over optical transmission cables.  Two types of optical cable may be used – single-mode (SM) or multi-mode (MM) – to enable bi-directional communication.

Typically, long-haul applications use single-mode fiber as the propagation properties of the fiber are designed to support long distances with less signal degradation (loss).

Multimode (MM) transmission systems use a wavelength of 850nm and is generally used in short-haul data/LAN applications. Single Mode fiber transmissions use 1310nm, 1550nm wavelengths to send data over much greater distances. Some transmission devices can support wavelength “multiplexing” to allow multiple simultaneous unidirectional or bidirectional transmissions on a single fiber.

Radio Frequency over Glass (RFoG) is a means of video distribution for analog RF carries that primarily uses SIngle Mode Fiber Optics. Multimode fiber optics has a physical property limitation of 5 6-Mhz RF carriers.

The power budget of an optical transmission network refers to the measurable amount of acceptable signal loss that can occur over the optical medium between two locations. The longer the distance, the more loss is experienced. If the loss over the span of optical cable is too great, the signal cannot be decoded by the receiver at the receiving end, and the “power budget” is said to have been exceeded.

A simple fiber optic transmission system consists of a transmitter on one end of the fiber, and a receiver on the other end, and the fiber optic medium (cable) connects them. Bi-directional transmission systems have a transmitter and receiver on each end (combined devices are called transceivers) and may use one or two optical cables depending on the technology of the transceivers used.

Fiber optic transmission systems take electrical information and converts it into pulses of light (turning it on and off really fast) to create a pattern of the information to be communicated. The receiver decodes the pattern and converts it back to electrical signals.

FTTB – Fiber to the Building – is a term used to describe a type of fiber optic cable installation that connects two locations together, usually from a service provider to their customer’s location. FTTB applications use active or passive optical networks to distribute shared signals over the fiber optic cable. The signals are often distributed through the customer location to end-users using additional fiber optic distribution, RF distribution, or even active Ethernet medium.

Data Over Cable Service Interface Specifications (DOCSIS) is an international telecommunications standard defined by the Society of Cable Television Engineers (SCTE) that defines a method of bi-directional data transmission over coaxial or hybrid fiber-coaxial cable television (CATV) systems. DOCSIS systems generally support high-speed internet, Voice over IP, and over-the-top video services.

DOCSIS 3.1 uses different transmission modulation methods and error correction methods than DOCSIS 3.0, which results in improved reliability, and faster download and upload speeds for the end consumer.

DOCSIS 3.0 systems can use up to 32 RF channels and deliver a  maximum download speed of approximately 1.2 Gbps depending on the CMTS and the capability of the CMTS and the cable modem (i.e, the number of upstream channels the modem can support simultaneously.)

DOCSIS 3.1 has a maximum downstream capacity of 10 Gpbs depending on the number of OFDM channels deployed at the CMTS. The overall maximum upstream capacity can be as high as 1-2 Gbps depending on the number of OFDMA upstream channels and ATDMA channels deployed. The individual user experience is based on the capability of the cable modem which is usually limited to 2 OFDM channels and therefore 3.7 Gpbs (theoretical maximum).

ATDMA (3.0) and OFDMA (3.1) upstream channels can be configured on different carriers with no overlapping. SCQAM (3.0) and OFDM (3.1) channels can also be configured on different carriers so that both DOCSIS 3.0 and 3.1 modems will work on the same service group. Many DOCSIS 3.1 modems can operate in “mixed-mode” and will use 3.1 and 3.0 channels simultaneously.

Other than the CMTS and the cable modems, it’s possible to need to change the passive components (like the diplex filter) and the active components (like amps and line-extenders) to support the spectrum allocated for the new environment. Many DOCSIS 3.0 deployments are using a “low-split” RF design, where the upstream is limited to 42Mhz. To really leverage the potential of DOCSIS 3.1, you need to change the “split” of the RF spectrum to a higher value – at least 65 Mhz or 85 Mhz – or go all the way to 208 Mhz that DOCSIS 3.1 recommends to achieve the maximum upstream bandwidth potential. Changing the split point means relocating non-DOCSIS service (video channels) to different downstream channels to allow more upstream capacity.

For analog – the desired value is between 0 dB and +6 dB.  For digital (QAM), we typically run 8 to 10 dB lower, so -10 to 0 dBmV at the TV set is acceptable.

For our BIDA 5800, the minimum input level is as follows: 30 dB gain amps need 14 dBmV input level.

For our BIDA 5900, the minimum input level is as follows: 43 dB gain amps need +1 dBmV input level.

You can use 4 US channels. Please note that they are combined inside the BT-CMTS-3000 and the total throughput depends on the CM config file and the speed of your main internet pipe and how many other CM are active. For example, in our lab, we have tested and we can achieve a total of up to 70 Mbits on a single cable modem if the other cable modems are not active. The throughput depends on the overall system design.

We have found that 20-30 inch-pounds are acceptable for those devices

You can add more channels with a minimal additional loss, by using a Tap or Directional coupler in the backward direction. For example, if you want to add 2 more channels, use the SRT-2A-14 dB value. Put this in backward at the output of the HPC-8 (the top right port of the SRT-2A would go to the HPC-8 output, the top right port would be your final output) and it will add 2 more ports with a similar combining loss. The HPC-8 will now have an additional 2 dB loss (originally 12 dB loss) and the two new ports will also have 14 dB insertion loss. As long as the fiber transmitter can handle this 2 dB additional loss, it should work with no additional problems.

The OC-12 could be used as a splitter.  It will lose 18 dB of signal during the splitting process.  It is recommended to verify that you have enough signal going to each outlet, to support this amount of loss, along with the loss of the cable lengths.  You would need a Field Strength Meter, like our BT-QAM-PRO or BTPRO-1000, to be able to measure the levels and verify signal strength.

It is possible that an amplifier may be required, but without knowing your system layout and losses, I could not say for sure what amplifier, if any, would be best for your application.

These amplifiers are rated at 36/44 dBmV output, which means, with full channel loading (up to 860 MHz, channel 135), and operating at the rated output (36 dBmV on channel 2, 44 dBmV on channel 135), it will exhibit the specified distortion characteristics (for the BODA-86-30P, CTB = -62dB). Changes in the output level or number of channels will affect the overall performance of the amplifier. Without fully understanding the effect of these changes, it is strongly recommended to operate the amplifier at its rated output.

Every doubling of amplifiers drops the CTB distortion by 6 dB, and (per FCC) you don’t want to fall below -51 dB CTB and still be able to maintain good pictures. CTB for that amp starting at -62 dB, you could safely run 3 amplifiers in series before reaching the FCC spec. There could be a total of 10 or more amps in the system, but as long as you are not going through more than 3 from the headend to any outlet, it only counts as 3 in series.

That unit has a ‘hidden’ admin page, to change IP addresses.  You need to log into the unit first as Admin.  Then in the address bar of the web browser, after the IP address, wipe out anything else and put “/Admin.html”.  So after you login, and change the address, the whole address should be http://172.16.70.1/Admin.html.  Then hit enter, it will take you to the Admin page where you can change IP addresses and login info.

With different length cables, especially the difference between 50′ and 300′, an even split like the DFCS-24 would not be your best option.

Typically, with different lengths, we would group them into similar lengths, like 50-100′, 100-150′, etc., and use multi-port taps to feed each group of cables. This way, you get much closer signal levels at each outlet location. Our SRT series taps work well for that, typically the SRT-4A 4-port or SRT-8A 8-port taps.

As for the amplifier, it would depend on the incoming signal level, as to which amp would be best for your application. We have off-air amps like the MUVB series, and we also have the BIDA series amps that could work, but again, it depends on your incoming signal level, as to which amp would work best for your application.

The input to the first BIDA amplifier stage needs to be as flat as possible, all channels the same level. So, if you are coming into the amp at 20 dBmV on channel 2, and 17 dBmV on the high channel (ch. 117 for 750 MHz), then we suggest a 3 dB equalizer. If you are coming in at 20/15 dBmV on low and high channels, we would suggest a 6 dB equalizer. It is better to have a 1 or 2 dB forward tilt, than a reverse tilt into the first amp stage.

You would most likely need an amplifier to use with the DFCS-32 splitter.  The DFCS-32 loses about 19 dB, so if you use the BIDA 100A-30 amplifier, that would make up for the splitter loss, and provide enough signal to the cable boxes.

The BIDA 100A-43 amplifier is looking for a 1 – 5 dBmV input level. The BIDA 86B-30 amp is looking for 14 to 17 dBmV input level. If you ‘overload’ either of these inputs, you will get distortions on the pictures, in the form of wavy lines in the picture, artifacts in the background, or other symptoms that the picture is not good (snowy pictures indicate too low signal). If you are running digital only channels, you will not see the same issues with the pictures, but you would get tiling and freezing pictures.

Yes, you can run analog and clear QAM signals over the same coax network, splitters and taps. Typically, when combining analog and digital, the digital signals are 8 to 10 dB lower than analog. And typically, the analog channels are run on lower frequencies, with digital above them, and with a 1- or 2-channel guard band, but they can be run adjacent channel as well.

Push-Pull amplifiers have a little lower distortion specification than Power Doubling. If you have more than two amplifiers in series in the system (not total amps in the system, but total number of amps the signal passes through to get to the furthest outlet) it is recommended to use the Power Doubling amplifiers, to minimize overall distortion. You can typically go up to 3 or 4 amps in series with power doubling, and still maintain FCC spec on distortion.

The SRT series has been around longer. The DGT series was created in the past few years, for the Digital signals. The DGT  series has undergone additional testing to become “Digital Certified” – meaning it has passed additional testing to be suitable for digital signals.

The SRT series has been installed in tens, if not hundreds, of thousands of digital systems, without issue. The biggest difference is that the SRT doesn’t have that additional testing certification. Both series will work equally well, but if you need a component that is digitally certified, go with the DGT.

Output level minus gain gives you minimum input level needed to get the rated output.

If your minimum is -3dBmV, and you hit it with +3dBmV, you are getting better noise, but a little worse distortion through the amp. If this is the only amp in the system, not a worry. If this is 3 or 4 amps into the system, it may cause too much distortion.

There is no specific marketing spec sheet for the BIDA-CE equalizers.  But I can tell you that they are pretty linear.  So if you are coming in to an amplifier at 26/20 dBmV, and use a 6 dB CE, there will roughly 20/20 (plus an additional 1 dB insertion loss across the board), making the final output of the CE 19/19 dBmV.

To figure out a level in the middle, you’d have to break down the frequencies.  50 to 860 MHz is a total of 810 MHz, middle of that is 405 MHz.  So at 455 MHz is the middle of the range, in a 6 dB CE, there is 3 dB loss.  Spit that again, and at 657.5 MHz, there is only 1.5 dB loss.

Verify the following settings under the “QAM” tab:
1. Output Control is “ON”.
2. CW Control is not checked.
3. Output Channel /Frequency is selected.
4. Final Output Level is set appropriately based on system requirements.

Verify the following setting under the “TS Config” tab:
Multiplexed MPTS Output Configuration > TS Bitrate – “QAM Modulator” must be selected.

Ensure “QAM Modulator” option has been selected under “TS Bitrate” on the “Main > QAM” screen

Here are a few of the units we found that will not work with standard QAM; Extron ATV 200 HD tuner, Contemporary Research 232-ATSC (the newer 232-ATSC+ works fine), some Sansui TV sets, & Digital stream DCS1000 Digital Cable STB.

Some devices will only recognize inverted QAM signals, check the software version of the DDQ module. IF the version is 1.7 then the QAM out is normal, if version 5.7 then the QAM is inverted. Contact Blonder Tongue technical support for additional help and for the upgrade files.

Yes, both the HDE-2H/2S-QAM and HDE-4S-QAM allows the user to add audio from one of the other inputs (analog audio, digital audio or audio from the HDMI input). The unit allows the mixing of any of the audio and video inputs.

No, the unit cannot add two different audio sources together. It can take the audio from any of its input sources and embed them with any of its video inputs, but only one audio source can be embedded at a time.

The unit can pass multiple audio channels, if they are already embedded on the SDI input stream.

The units will internally generate color bars (720p @ 60fps).

The unit is not designed to work with a 1080p input source. The inputs formats supported are: 480i, 720p, & 1080i.

To reset the IP address to the default address, the unit must be powered up and the reset button held in for at least 10 seconds. This helps prevent accidental resets from momentary button taps.

19 Mbps is the lowest you can set, but if you disable stuffing in the IP tab, it will not fill to 19 Mbps; it will only pass the actual data, reducing the overall bitrate.

The input lights will also flash if the QAM out is turned off or put in CW mode for that channel. If you are using IP output only, and have turned off the QAM output, the lights will flash.

Upon logging into the unit, go to the video tab to chance video parameters, and audio tab for audio parameters. Top line item for each input source, which is a drop-down list. Select the inputs you want and click “SAVE” button at the bottom of each page before moving on.

The attached white paper will shed some light on this for you.

White Paper: DESIGNING THE DISTRIBUTION SYSTEM

No, the AP-60-860A has three operating modes.
i. Analog input to Analog Output
ii. QAM input to QAM Output
iii. QAM/8VSB input to Analog Output

No, the MDDM will pass only ONE program from the selected RF channel, not the entire channel.

Yes, this unit is field upgradeable, through the Mini-USB port.

Check that the video profile is set to MP@HL on the Drake DSE24. Some tuners will not lock in if the profile is not correct. Profile settings for the DSE24 should be MP@ML for 480 @30fps and MP@HL for 720 @ 60fps or 1080 @ 30fps.

Firmware must be upgraded to version 3.7 in order to lock to these transponders. After upgrading to V 3.7, QTM will lock in “Manual” as well as “Auto” modes.

The 5800/5900 series BIDA is set for PASSIVE return capability out of the box. To activate the return amplifier you must open the unit and move jumpers around to enable the return amplifier stage.

No, it is strongly recommended to use APC (angle polished connectors) throughout the system. Anywhere there is a flat connection in the fiber plant, reflections can occur, causing problems with the signal. Worst-case scenario is where the flat connector is near the transmitter, and it could reflect enough signal back into the transmitter as to cause damage.

These units are rated to 860 MHz, so you could run up to channel 135. If these units see more than 110 channels, you will need to lower the total input level into the unit, so the composite power does not exceed operating input.

NO. The CEF was designed for analog channels, and we do not make it for digital currently.

RFreq™ lists channel band edges, center frequency and legacy analog visual and carrier frequencies.  Typically when referring to digital TV broadcasts in 8VSB or digital CATV QAM channels, the center frequencies are used.  This app is for frequency referencing only, and requires the user to know what the source is.  The digital transition (ie. the death of analog) primarily refers to when full power TV stations moved to digital broadcasts in 2009, or the fact that large CATV plants are moving toward all digital.  However, as things are still changing, and for many niche/legacy applications where analog is still being used (like low power and translator broadcasts; businesses and schools CATV …), it is helpful to technical personnel to have easy access to all of the frequency information (which is why we developed RFreq™). Please see Apps By Blonder Tongue for more information.