Need help with Tone Stack Calculator

[martin manning]

That looks fine to me. Put in -6 for the input and set the units to dB Power, and get amplitude 0.5 (reduced by a factor of 2) for the output.

[matt h]

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[martin manning]

All types of dB are power ratios by definition, so I don't know what to make of the "dB signal" unit.

[ToneMerc]

All types of dB are power ratios by definition, so I don't know what to make of the "dB signal" unit.

Martin, that's correct. That "signal" is in reference to laser transmit output power, which in this case is 0dB output. Actually the signal should be labeled as dBm.

TM

[martin manning]

It still seems screwed up. Regardless of what the reference power is, if you give it -6 Signal dB assuming that is a power ratio, the result shows -6dB Signal (echoing the input), -12 dB power (which is NOT correct), and 0.25 in amplitude (which IS correct in that -6 dB is 1/4 power).

[matt h]

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[roberto]

As far as I remember, it's like that:

One Bel is a ratio between two powers in which the first is ten times the second, and a ratio between two voltages in which the square of the first is ten times the square of the second (we can say the ratio between voltages is square root of ten, so 3.14something).

The deciBel comes consequently being one tenth of that.

This is why we use 10 x Log (W2/W1) for power ratios and 20 x Log (V2/V1) for voltages/currents ratios. So a 6dB is four times considering power ratios and two times for voltage/current ratios.

The dBm is just a reference value of 1mW, while the dBu is 1 dBm on a 600 Ohm load, so 0.775 V.

[matt h]

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