There is a difference between successive approximation type DVM and linear ramp type DVM
| Successive approximation type DVM | Linear ramp type DVM |
|---|---|
| Unknown voltage is successfully compared with the output of digital to analog converter. | Unknown voltage is compared with either positive or negative going ramp. |
| Output reading is obtained after successive decision taken by logic circuit. So the probability of error in output reading is more. | Probability of error in the output reading is less. |
| Output signal cannot be easily digitized. | Since the output is in terms of time, this signal can be easily digitized. |
| Speed of operation is less. | Speed of operation is more. |
| Resolution upto maximum 5 digits can be obtained. | Resolution is directly proportional to the frequency of local oscillator and it can be improved by increasing this frequency. |
| Accuracy depends on accuracy of internal reference and accuracy of digital to analog converter. | Accuracy depends on linearity and slope of ramp. As well as it depends on stability of local oscillator. |