# Decibels hertz relationship

### Difference Between Decibel and Hertz - senshido.info

The decibel (symbol: dB) is a unit of measurement used to express the ratio of one value of a The extra factor of two is due to the logarithm of the quadratic relationship between power and amplitude. .. The suffix is often connected with a dash (dB-Hz), with a space (dB HL), with no intervening character (dBm). Vibrating objects create waves of energy that change the pressure of the surrounding air. These pressure changes are picked up by the human ear and. Hertz is the standard unit of measurement used to calculate the frequency of these oscillations. The average, healthy human can detect sounds at the zero decibel level, but a person with really good hearing can detect sound at -5 decibels. The relationship between Hertz and.

A planet revolving around the sun is a periodic motion. A satellite orbiting around the earth is a periodic motion even the motion of a balance ball set is a periodic motion. Most of the periodic motions we encounter are circular, linear or semi-circular.

A periodic motion has a frequency. For simplicity, we take frequency as the occurrences per second. Periodic motions can be either uniform or non-uniform. A uniform one can have a uniform angular velocity.

Functions such as amplitude modulation can have double periods. They are periodic functions encapsulated in other periodic functions. The inverse of the frequency of the periodic motion gives the time for a period.

For example, it can be combined with "m" for "milliwatt" to produce the " dBm ". A power level of 0 dBm corresponds to one milliwatt, and 1 dBm is one decibel greater about 1. In professional audio specifications, a popular unit is the dBu.

## Difference Between Decibel and Hertz

When used in a ohm circuit historically, the standard reference impedance in telephone circuitsdBu and dBm are identical. Video and digital imaging[ edit ] In connection with video and digital image sensorsdecibels generally represent ratios of video voltages or digitized light intensities, using 20 log of the ratio, even when the represented optical power is directly proportional to the voltage, not to its square, as in a CCD imager where response voltage is linear in intensity.

Most commonly, quantities called "dynamic range" or "signal-to-noise" of the camera would be specified in 20 log dB, but in related contexts e. Photographers typically use an alternative base-2 log unit, the stopto describe light intensity ratios or dynamic range.

### How can i convert dB to Hz? is there any relation between them? | Yahoo Questions/Réponses

Suffixes and reference values[ edit ] Suffixes are commonly attached to the basic dB unit in order to indicate the reference value by which the ratio is calculated. The successive compressions of the sound wave are 75 centimetres apart. Sound velocity depends on medium such as metal, water or air and temperature.

The velocity of sound propagating through air is In the following exercise, you will have an opportunity of seeing for yourself how sound velocity is affected when the air temperature changes. What is the speed of sound on a cold winter day oC? Sounds higher than 20 kHz are called ultrasoundswhile sounds below 16 Hz are called infrasounds. C cent, from Lat. It stands for one hundredth of an equal-tempered semitone.

### What is dB (decibel) and Frequency? What is the decibel scale?

In other words, one octave consists of cents. An equal-tempered whole tone can be expressed as C, while an equal-tempered fifth would be C, or seven semitones.

Cents are used to express the size of individual microintervalsbut also to illustrate the ratio of any given interval such as a second or a third. The differences between the intervals of different tuning systems can be compared easily when the intervals are expressed as cents. In an equal-tempered system the intervals are always multiples of one hundred.

The figure below shows a comparison of typical fraction notations of microintervals and the corresponding values in cents between the tones E and F. As the figure illustrates, a quarter tone is 50 C, while an eighth tone is 25 C.