New answers tagged

4

The H4n is a great device, if pricey (but not overly priced.) Balanced and unbalanced/single-ended I guess the first thing to discuss is the meaning of balanced and unbalanced, since it's more a technical issue between experts and has far less real meaning to consumers. Between experts, as I've interpreted what I have read (as I'm no expert here, just a ...


4

That may come as a surprise, but all those different interfaces, such as headphone connector, line level connectors, and mic connectors need to have their own parameters such as voltage ranges and impedances to best work with the thing it is connected to. So an headphone output connected to line or mic input may not sound so good because they don't have ...


8

It's actually number 1: It doesn't matter. An audio amplifier can (almost) always drive a lighter load than it is designed for. The "maximum 600 Ohms" claim is most likely related to the output voltage that the headphone amplifier can provide; higher-impedance headphones need more voltage. This is irrelevant for your recorder.


2

Output Impedance MONITOR: 1⁄4”TRS, impedance-balanced 51Ω. Unity gain. This means the output is the same as your input. Recorder will be high impedance like 10kΩ so there is no attenuation or effect on the headphone output. (Update 480 kOhm) The speaker output will be << 1 Ohm so a load from 8 to 600 ohms does not attenuate much but affects power ...


0

You sound like you are measuring the superimposed reflections from two transitions. Now if both transitions are identical, and if there was negligible loss between them, you may expect those two reflections to cancel at some frequencies, and be 6dB (double voltage) relative to either one at the worst. So you may expect your predicted 25dB to be 19dB on the ...


0

What is a good way to connect filters to maintain 50 Ohms on all 4 ports of the triplexer? The output ports will likely maintain their 50 Ω characteristics if each sees a 50 Ω source impedance at their input. So, each filter needs to be fed separately from a 50 Ω source. This then boils down to making a matching network for each filter's input port that ...


0

You could use a couple 3 dB splitters or redesign the filter to crossover the 2m signal such it is high impedance out of band and 1 splitter for the 2 higher frequencies that are closer together.


1

Do I need to worry about impedance matching between the microcontroller and 74LVC1T45 to reduce reflections? No, because the source driver has no characteristic impedance. In addition, transmission line effects usually don't have an affect until ~50MHz. What will affect the signals is capacitance which will affect the rise times, so try and keep that low.


1

Impedance match is affected somewhat in the unequal line length skew of differential pulses and mismatched impedance with 3mm on a 2GHz signal. Usually it affects a few dynamic pixels when other noise is present such as CM ground noise from SMPS. Below is shown for 50 to 120 ohm 3mm stripline @ 2Ghz . It depends on your resolution , signal rate and CMRR of ...


2

As mentioned in the comments, headphones and amplifiers do not match impedance. Rather the source device is low impedance relative to the load. For example a good headphone output might be less than 1 ohm while headphones are at least 16 ohms. The only purpose those impedance sensing circuits serve is to adjust the volume setting range. The manufacturer ...


4

There's not a lot of difference (a couple percent between the two results) when the same trace widths are specified. 49.9 vs. 48.7 ohms. The accuracy is given as ~10% on the first calculator and unspecified on the other. Different calculators may use different formulas, with different accuracy and different ranges of applicability. Some use the formulas in ...


0

So long since that question came up but I have discovered it recently and would like to add some thoughts: Considering tolerances in antenna impedance (first point in these smith charts) I would probably prefer to choose the second approach. Thats because if the antenna impedance changes slightly there is a much higher deviation of the second point's ...


0

The composite video output needs to have 75 ohm output impedance, and the voltage levels needs to be 1Vpp when terminated into 75 ohms input device. The 1Vpp is from sync tip to white, with 300mV for sync and 700mV for white. Color modulation adds some amplitude, so e.g 100% yellow has 1.233Vpp. Basically you need a DAC with sampling rate of 17.734475 MHz to ...


0

The composite signal will have a swing as much as 1V or so, including sync, driving into 75 ohms. Plan for 1.1V. This can be driven by a DAC directly assuming it has a suitable swing (for example, a ‘video DAC’). A DAC of at least 10 bits, followed by a buffer with a low-pass reconstruction filter is recommended. The video output signal can be referenced to ...


1

Yes, you can tie both DP and DN signals together to form a single diff pair. At USB 2.0 speeds the way you tie them together is not very important. Of course you will always have a long nub in the form of the unused wire in the cable that can degrade the signal, especially with longer cables. You can get around this by using multiplexer ICs designed for this ...


Top 50 recent answers are included