# REPORT ON RELATIVE CALIBRATION OF THE MICROPHONES

## RESULTS OBTAINED

* We have done three cases for the relative calibration i.e, three types of signals were given to the speaker
- sine wave with amplitude 2mV, frequency 200Hz and time 100sec
- chirp signal with amplitude 1mV, frequency from 250Hz-2500Hz and time 100sec
- chirp signal with amplitude 2mV, frequency from 250Hz-2500Hz and time 100sec

### sine wave with amplitude 2mV, frequency 200Hz and time of 100sec

* the pressure time series data of the 5 microphones which includes absolutely calibrated microphone is shown below


* the pressure time series data of the five microphones with time shown upto 1sec in the box.


* the pressure time series data of the five microphones with time shown upto 5sec in the box.


* the pressure frequency domain of the five microphones is shown below


* the detailed view of pressure frequency domain for the five microphones is shown below


* rms value of pressures of the microphones are shown below

| rms value of the pressure | value |
| ----------- | ----------- |
| rms voltage of input signal | $\sqrt2$ mV
| absolutely calibrated | $5.0945$ Pa |
| microphone 1 | $4.3759$ Pa|
| microphone 2 | $3.8967$ Pa |
| microphone 3 | $6.2414$ Pa |
| microphone 4 | $4.2038$ Pa |

### chirp signal with amplitude 1mV, frequency from 250Hz-2500Hz and time 100sec

* the pressure time series data of the 5 microphones which includes absolutely calibrated microphone is shown below


* the pressure time series data of the five microphones with time shown upto 1sec in the box


* the pressure time series data of the five microphones with time shown upto 5sec in the box


* the pressure frequency domain of the five microphones is shown below


* the detailed view of pressure frequency domain for the five microphones is shown below


* rms value of pressures of the microphones are shown below

| rms value of the pressure | value |
| ----------- | ----------- |
| rms voltage of input signal | $0.7053$ mV
| absolutely calibrated | $2.4462$ Pa |
| microphone 1 | $2.7339$ Pa|
| microphone 2 | $2.7433$ Pa |
| microphone 3 | $3.0999$ Pa |
| microphone 4 | $3.2027$ Pa |

### chirp signal with amplitude 2mV, frequency from 250Hz-2500Hz and time 100sec

* the pressure time series data of the 5 microphones which includes absolutely calibrated microphone is shown below


* the pressure time series data of the five microphones with time shown upto 1sec in the box


* the pressure time series data of the five microphones with time shown upto 5sec in the box


* the pressure frequency domain of the five microphones is shown below


* the detailed view of pressure frequency domain for the five microphones is shown below


* rms value of pressures of the microphones are shown below

| rms value of the pressure | value |
| ----------- | ----------- |
| rms voltage of input signal | $\sqrt2$ mV
| absolutely calibrated | $3.1395$ Pa |
| microphone 1 | $3.5455$ Pa|
| microphone 2 | $3.5019$ Pa |
| microphone 3 | $3.6339$ Pa |
| microphone 4 | $3.9622$ Pa |