#Hdmi versions how to
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#Hdmi versions software

The key challenge for a signal generator is to provide a fullcomplement of highly accurate signals and the ability to preciselycontrol their parameters.įor performing minimum differential sensitivity tests, a resolutionof 20mV is required. TMDS signal generation plays a pivotal role in the Sinktests.įigure4: Shown is an integrated sink testing system based on a closed-loopmechanism When selecting the right equipment for the HDMI CTS test setup, itis important to understand the necessary aspects that must beaddressed. Three measurements are performed over two test cases: (a)data jitter frequency at 500kHz and clock jitter frequency at 10MHz,and (b) data jitter frequency at 1MHz and clock jitter frequency at7MHz. Several measurements are carried out by injecting a specified amountof jitter. The amount of jitter that the sink device is able to tolerateis compared against the limits for compliance. Specified amounts of jitter are injectedin steps (from low to high jitter) into the transmitted Transition Minimized Differential Signaling(TMDS) signal until the sink device fails to recover thesignal. The standarddefines the limit as 0.3*Tbit. One of the most critical characteristics of a sink device is itstolerance to specified levels of jitter in the signals. Notice therichness of information that ensures clear and compelling measurements. This can mean unacceptably long acquisition and test times.Fortunately, there are sophisticated techniques such as FastAcq onDigital Phosphor Oscilloscopes (DPO) that enhance the trigger re-armrates and deliver over 300,000wfms/s.įigure 3 above demonstratesthe clock duty cycle test using the FastAcq technology. Nominally, oscilloscope trigger re-arm rates are of theorder of about 100wfms/s. Trigger re-arm rates of the oscilloscope then takecenter stage. It's important that the variance in duty cycleis measured over a large number of acquired signals.įigure3: This clock jitter test used DPO technology.Īs per the CTS, a minimum of 10,000 triggered waveforms are requiredfor test purposes. The CTS also defines the margin to be +10 percent from the nominal50 percent duty cycle.

duty cycle jitter is an excellent method ofassessing deterministic jitter. Considering the bit rate up to 3.4Gbps, the minimumoscilloscope record length is above 16M with high-speed sampling rate(above 10GSps).Īt the nerve center of any transmission system is the clock jitter.The jitter test checks to ensure that the clock signal is not carryingexcessive jitter – e.g. With 16M/20M record length,at least 400,000 unit intervals (UI) can be captured forlower-resolution signals, and over 2.6M UI for higher resolutiondevices. This ensures that at least 400,000 unit intervals (or Tbit) areaccumulated for building the eye diagram.

Meanwhile, to ensure adequate representation of signalcharacteristics, the CTS 1.3b specifies a minimum oscilloscope recordlength to acquire the data signal. Figure 2 above isan example of HDMI 1.3 source test results using HDMI compliance testsoftware. In terms of the key instrument, to test HDMI 1.3 signals need aminimum 8GHz real-time oscilloscope in which HDMI compliance testsoftware is running.

#Hdmi versions software

Engineers need to integrate several instruments into acomplete, flexible and cost-effective solution.Ī capable, integrated solution enables fast eye-diagram renderingand jitter verification, required to accumulate huge waveforms withinas short a time period as possible.Īlso, signal generators need to operate in a closed loop toautomatically perform the needed complex cable and sink tests using”one-button” compliance test software resident on an oscilloscope.įigure2: Shown are HDMI source compliance test results.Ī complete test solution for HDMI CTS 1.3b includes high-performancehardware and comprehensive software for design and test engineers inconsumer electronics, semiconductor and cable manufacturers.

#Hdmi versions how to

However, thekey is how to choose the right test platform to simplify the latestHDMI designs and to ensure compliance with the latest testrequirements. Per HDMI CTS 1.3b specifications, the complete compliance testsolution includes real-time oscilloscopes, sampling oscilloscopes,signal generators, differential probes and test fixtures. While it is recommended to perform as many tests as possible, thecore electrical tests are critical for compliance. Figure 1 above shows themajor elements of the HDMI transmission system – source, cable andsink.