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Questions tagged [video]

Specify video format, e.g. NTSC, ATSC, VGA, etc.

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24
votes
2answers
6k views

What is this inductor symbol from a video circuit?

This is from the datasheet for the TDA8217 PAL decoder and video processor. This is the "Applicaton Diagram". The circled item is unfamiliar to me, I asked at my local electronic components ...
0
votes
1answer
34 views

Do I have match impedance while routing PAL video tracks?

I am designing a PCB with PAL video output. PCB contains 50ohm and 100 ohm traces. The connection between RF coax connector is very close. So 75 ohm traces are 80 micron for my stack-up. I am confused ...
0
votes
2answers
68 views

Hardware composite video overlay

I am building a setup to make more inputs on a composite monitor (in fact it's a VGA monitor with a composite-to-VGA converter on it but the overlay needs to be composite) and everything will be ...
0
votes
1answer
38 views

Purpose of divide-by-2 (or CLK/2) on a video pixel clock generator ICs

I've been looking into some video clock generator chips and almost all of them have a divide-by-2 or CLK/2 output pin (in addition to the normal CLK out). What would be the purpose or application for ...
0
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0answers
15 views

LA72910V Demodulator and Modulator Noise Problem

The project includes a DC power supply that supplies two cards and provides a network. The video signal is modulated through LA72910V whether a card is demodulated in the other card. There is no ...
0
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2answers
46 views
0
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2answers
62 views

PAL termination problem?

I have a circuit like this. Input of circuit is PAL signal. Output of circuit whose AC coupled version. Input Output But HSYNC part in the output looks like mirrored. It should be more negative ...
1
vote
1answer
117 views

8-bit VGA DAC Design Question

I am being driven up the wall with designing an 8-bit VGA DAC for an embedded application. Everywhere I've researched highlights the necessity for "impedance matching" the 75 ohm termination ...
0
votes
2answers
101 views

Understanding PAL signal on PCB

I have a decoder circuit that includes TW9900 video decoder. The decoder doesn't work properly. There is a matching and AC coupling circuit on analog inputs of the decoder. To finding the problem, i ...
1
vote
0answers
40 views

Composite video signal detection problem?

I have an android headunit and I installed a reversing camera to it. The problem is that the headunit does not seem to detect the camera signal if the environment is too bright. It just shows black ...
0
votes
2answers
93 views

Determining Blanking for HDMI Transmitter

I am working on a project which produces a video output over an HDMI connector. The driver I am using is the Texas Instruments TFP410PAP. The image I am attempting to display is WVGA, 800 x 480 ...
0
votes
1answer
80 views

Do front and back porches for digtal video really matter?

I am developing an LCD controller, and some of the code for my (third-party) timing generator includes horizontal and vertical front/back porch and vsync/hsync pulse time information for a different ...
1
vote
0answers
73 views

AD725 luma trap implementation

This question is related to my issues implementing luma trap on my bread board when it appeared that I get better results through composite output by disconnecting luma trap circuit at all. However ...
1
vote
0answers
42 views

AXI4-Stream TVALID stuck low between VDMA and video output block

I'm trying to buffer a single frame of video using a VDMA block on a Trenz TE0712 board (artix-7 based development board), based on a few examples (specifically Numato's framebuffer example and Xilinx'...
1
vote
2answers
137 views

Is there any modern video connector you can use royalties free?

I would like to make several hundreds of a device with video out. It seems every video connector involves huge fees for licensing - is there anyway around this?
0
votes
1answer
117 views

How can I delay a digital signal

I am generating a video signal using an AD724 and a microcontroller, which is genlocked to another video signal from a camera, and am using an SN74lVC2G53 analog switch to switch between signals. I'm ...
1
vote
0answers
29 views

DS90UB948-Q1 internal pattern generator

Does anyone have prior experience with DS90UB948-Q1 FPD-Link III Deserializer deserialiser from Texas Instruments ? I am trying to configure the internal pattern generator block sending I2C commands. ...
5
votes
1answer
113 views

Why should crystal switching be avoided?

The MC44144 is a gated phase locked loop intended for video applications that is described in its datasheet as "sensitive to shunt capacitance" and that "crystal switching should be avoided". What ...
0
votes
1answer
36 views

Digital signal into the video cable

The input signal is simply composite sync signal, without any additional video information. It is CMOS - 0 to 5V levels. I need the same type of signal to appear in the cable along with the RGB lines. ...
1
vote
1answer
102 views

Un-moving “static” image from VGA controller

I am reverse-engineering a daughter card which uses a ADV7125KSTZ140 VGA video DAC driven by a FPGA. The FPGA is a Xilinx Spartan 3E programmed by an off-board processor using slave-serial mode, ...
3
votes
1answer
113 views

Why does DMA send the first byte as soon as it is enabled?

I'm using DMA to send data to GPIOF which is configured as a parallel bus. DMA is being driven by update events on TIM8. TIM8 is configured in slave mode and starts on an output compare event from ...
0
votes
0answers
79 views

How to convert arcade RGB video (2-5v p-p) to VGA (0-0.7v)?

I'm trying to convert arcade video signals (JAMMA) to VGA specifications. From what I've gathered, arcade video signals aren't standardized. They can range from 0v-2v or 0v-5v, etc. However, VGA ...
0
votes
1answer
50 views

Choosing capacitors for AD725 encoder

This question generally applies to many situations, but in this case I am trying to figure out the best choice (no limit to the perfection). I am stuck at both input coupling capacitor and output ...
-1
votes
2answers
135 views

Several questions on video circuits

Part 1: Looking into several old good home computer video output circuits I see the similarity I can not fully understand. They use diodes or transistors as a bias for the final output section. See ...
2
votes
2answers
140 views

Is it a mistake in AD725 and other datasheets?

During my research of the RGB video and encoders I see two ways chip manufacturers/circuit designers treating the outputs (several examples below): AD725 (Analog devices): capacitor then resistor ...
0
votes
1answer
79 views

Video clocking: crystal or generator?

The video processor (VDP) has 6*Fsc (21,47727 MHz) clock inputs, pins XTAL1 and XTAL2, which is inversion of XTAL1. Present circuit is built using quartz oscillator of above mentioned frequency, and ...
0
votes
1answer
107 views

How to avoid signal interference between 5 volt analog video signal and 415 volt servomotor and drivers, when working nearby

I am using a 5V borescope analog camera (Sony CCD, PAL/NTSC) for visualization purposes. This camera has a 20 meter 4 core wire, which transmits power and video signal to and from the camera. Along ...
2
votes
2answers
66 views

Practical question on high resolution to composite/S-video

I read many resources on the internet talking about NTSC, PAL, timing and voltage levels. But I have specific practical question, and I can not find definite answer to it. There're very helpful posts ...
3
votes
1answer
97 views

Connecting luma only output to composite input

In the course of troubleshooting this problem I reconnected RCA connector connected to the RCA input of my TV to the luma wire of AD725 in hope having precise and beautiful grayscale picture, but got ...
0
votes
0answers
15 views

Video AHD protocol documentation/stanard for implimentation?

Im looking for some form of documentation in which supplys the information to impliment the Analog High Definition (AHD) protocol, for knowledge, I am using an FPGA for reading data, and a Swann PRO-...
1
vote
0answers
40 views

Shift composite image right

The circuit is based on AD725 encoder, and the proto board is functioning relatively well. Here're the pics: NTSC mode: PAL mode: Circuit detects PAL or NTSC mode using MCU, and performs automatic ...
0
votes
2answers
125 views

How to scale down voltage of the the video signal without affecting input wire impedance

This is a question stemming from this one where I search for the root cause of AD725 displaying wrong colors. Current step have shown that I must be out of the spec for the input of the chip: my RGB ...
0
votes
0answers
57 views

How to bias an AC input composite video signal [duplicate]

This is a question about biasing 0V-referenced AC input signals to a positive single-ended signal. Even if the best solution for my question would be something else (and I'd like to hear about that, ...
4
votes
1answer
346 views

AD725ARZ wrong colors

I designed device based on AD725ARZ, datasheet is here. Device is built basing on the reference circuit diagram on page 12. TV is connected to composite output of the circuit. It does not have S-...
0
votes
4answers
132 views

AC-Coupling on Composite video

Many sources say that composite video input should be AC-coupled. Voltage levels for blank, black and white signal are also specified. How is it possible to detect these voltage levels after AC ...
0
votes
1answer
72 views

Why is 7:1 video serialization required?

I am trying to migrate portions of a ZYNQ design from one platform to another. Part of the project is based on Avnet's ALI3 touchscreen kit. From the docs: The 7-inch Zed Touch Display Kit includes ...
0
votes
1answer
65 views

Digital transmission of composite video [closed]

As the tittle suggest, I was thinking about making a wireless composite video transmission between a small camera (such as those sold for flying fpv) and a receiver. The two main specs it must have is ...
0
votes
1answer
87 views

3 way selector switch to Push Button switch

I have 3 way video switcher which uses selector switch, is it possible to change this to momentary push button? Project - I want watch 3 video feed from camera over 1 screen, with this selector ...
0
votes
1answer
29 views

Why would sdi to hdmi work, but not when I convert sdi to hdmi to dvi [closed]

I am transmitting video over sdi and converting from sdi to hdmi with an aja Hi5. This works, but if I convert that hdmi output into dvi, the output is either not detected, or constantly connects and ...
0
votes
1answer
47 views

Filter power supply for video signals

I'm drawing a board with an MCU (running at 32 MHz), some serials and an analog video section (mux and amplifiers). I kept the video section physically separated from the digital one: i.e. it's placed ...
12
votes
1answer
294 views

Troubleshooting a faulty filter circuit in a PAL CRT display

I have an old CRT monitor (Phillips CM8833) which I am attempting to repair. When displaying a composite PAL signal, it only shows a black and white image, but it is still able to display RGB signals ...
0
votes
1answer
99 views

Composite Video Driver Design - PAL

In the effort to understand early computers (systems revolving around the 6502 CPU). I have started studying their makeup, while the operation of the CPU & memory makes sense. I'm left stuck and ...
0
votes
2answers
109 views

Is there equalizer on the monitor's HD-SDI interface

Is there usually an equalizer on the monitor's HD-SDI input interface? In fact is it an requirement for HD-SDI monitors? Maybe HD-SDI signal is attenuated too much at the input of monitor, but ...
2
votes
0answers
80 views

Advice on upgrading a circuit design for s-video

I'd need some advice on a circuit, which generates analog video (s-video) from composite and Chroma (a mod inside an old Sinclair Spectrum computer). I haven't designed the circuit myself, but I ...
1
vote
1answer
281 views

Video sync generator IC

I have a board which is a PAL CCIR video sync generator card having SAA1043. The IC is accepting external sync signal from pin 15 and generating composite pulse on pin 26 and burst output on pin 1. ...
0
votes
0answers
40 views

Light illumination method for video camera and CV detection

My control application implements human face detection and recognition with using of CV library. My device uses usual VGA USB video camera. Problem: Good and uniform light illumination allows ...
0
votes
0answers
54 views

CXA1645 replacement - most convenient switching between PAL and NTSC

I have built NTSC encoder using CXA1645, and picture through composite out is great. Now I want to extend it to PAL, because output device encoder is attached to can operate in both modes, changing ...
0
votes
1answer
115 views

How can I attenuate a video signal in discrete steps using digital control? [closed]

I would like to use a μController to adjust the brightness of VGA/EGA RGB signal. My intention is to allow for a setting from "full brightness" (0% attenuation) to "completely dark/black" (whatever ...
0
votes
4answers
67 views

Video Protocol Without Required Speed

I am trying to output a video signal with a slow microcontroller (Arduino). I don't need anything fancy like HD or 30fps, and if it takes a second to update the frame that is fine. I was looking for ...
0
votes
1answer
219 views

HDMI to CSI Converter for raspberry pi [closed]

I am creating a HDMI to CSI converter, but i dont know if the wiring is correct and if i need to add any passive component. can you guys help me out? EasyEDA Project