Frequency Repeatability of Crystal Impedance Meter TS-683/TSM,

Quartz crystal uits, operated within the 10- to 90-Mc frequency range, were subjected to repeated frequency measurements after simulating recalibra tion of Crystal Impedance Meter TS-683TSM through readjustment of the oscillation amplitude level and test set frequency under calibration condi tions, i.e., with a resistor substituted for the crystal. Generally, it was found that the oscil lation frequency of plated AT resonators is critically dependent upon drive, the internal 0-150 microamperes meter cannot be used to adjust drive levels within accurate enough limits, and with a standardized procedure, frequency repeata bility of this type C.I. meter except for fre quencies above 75 Mc is better than one times ten to the minus seven power. Author