What are the types of measuring instruments?

Measuring instruments are: level , latitude and longitude, electromagnetic wave rangefinder and so on.

The concept of measuring instruments its basic content includes: accuracy, error, measurement standard equipment, length measurement, angle measurement, shape measurement, traditional optical instruments. Application in precision measurement and so on.

Measuring instruments have contact and optical trial measurement of two kinds (now used most) Contact: general measuring tools and 3D measuring tools (CMM also called three-dimensional) CMM also called three-dimensional , it can measure a lot of complex spatial dimensions: such as molds and automotive products.

Phase ranging method

The measuring line is emitted at one end and returned by the other end, then the phase difference between the emitted wave and the returned wave is measured by a phase discriminator. If the modulation frequency is f, the time experienced by the electromagnetic wave round trip is: where n is

the number of whole weeks in time t. Substituting t into the above formula for pulse ranging method, the distance D is: ,where λ is the known modulation wavelength is equivalent to the length of the ruler to measure the distance, n is equivalent to the number of whole feet on the range is less than the number of tails of a measuring tape length.

In order to determine the number of whole feet n, usually using variable frequency method and multi-level fixed frequency method. The former is to make the rangefinder modulation frequency within a certain range of continuous change, which is equivalent to continuous change the length of the measuring tape, so that it is exactly the energy exhaustion of the distance to be measured.

Ranging, time by time to change the frequency, so that less than the whole foot of the number of tails equal to zero. According to the number of times zero and the corresponding frequency value, you can determine the number of whole feet n ° when the use of multi-level fixed-frequency method, equivalent to the use of several different lengths of the measuring tape to measure the same distance. According to the phase difference measured with different frequencies, it can be solved for the whole number of weeks n, so as to find the distance D.