IEC 62884-1:2017 pdf download

IEC 62884-1:2017 pdf download.Measurement techniques of piezoelectric, dielectric and electrostatic oscillators
4 Test and measurement procedures
4.1 General The test and measurement procedures shall be carried out in accordance with the relevant detail specification.4.2.4 Power supplies DC power sources used in the testing of crystal controlled oscillators shall not have a ripple content large enough to effect the desired accuracy of measurement; AC power sources shall be transient free. When the ripple and/or the transient content of the power sources are critical to the measurement being performed, their effects shall be fully defined in the detail specification. 4.2.5 Precision of measurement The limits given in the detail specification are true values. Measurement inaccuracies shall be taken into account when evaluating the results. Precautions should be taken to reduce measurement errors to a minimum. 4.2.6 Precautions 4.2.6.1 Measurements The measurement circuits shown for specified electrical tests are the preferred circuits. Due allowance shall be made for any loading effects in cases where the measuring apparatus modifies the characteristics being examined. 4.2.6.2 Electrostatic sensitive devices Where the component is identified as electrostatic sensitive, precautions shall be taken to prevent damage from electrostatic charge before, during, and after test (see IEC 61 000-4-2). 4.2.7 Alternative test methods Measurements shall preferably be carried out using the methods specified. Any other method giving equivalent results may be used, except in case of dispute. NOTE “Equivalent” means that the value of the characteristic established by such other methods falls within the specified limits when measured by the specified method. 4.3 Visual inspection 4.3.1 General Unless otherwise specified, external visual examination shall be performed under normal factory lighting and visual conditions. 4.3.2 Visual test A Oscillator shall be visually examined to ensure that the condition, workmanship and finish are satisfactory. The marking shall be legible.
Oscillator shall be connected to the test circuit (see note to Figure 4) and placed in the environmental chamber as shown in Figure 4. The load and supply voltage(s) shall be as specified in the detail specification. Where the input power to Oscillator will be affected by forced air circulation, still air conditions shall be simulated by enclosing Oscillator in a draught shield, as described in 4.2.3. Readings of voltage and current shall be taken at the specified temperatures as stated in the detail specification (usually at the minimum and maximum of the operating temperature range, as well as at the reference temperature). The temperature will normally be taken as the reference point temperature on the surface of the draught shield, when used. If peak power is specified, the transient values of voltage and current shall be measured when the environmental chamber is adjusted to each of the specified temperatures. In this case, it can be necessary to attach a recording meter to the ammeter and/or voltmeter, so as to measure adequately the transient values. Oscillator and oven shall be allowed to reach thermal equilibrium at the operating temperature, while unenergized, prior to any measurement of peak power. Should peak power be required, the environmental chamber shall have a thermal time constant significantly less than that of the oven-oscillator combination being measured.
Oscillator shall be connected, as shown in Figure 5, to the specified supply voltage and load. It shall be allowed to stabilize for the specified time under normal operating conditions. The frequency shall then be measured on the frequency counter. The frequency may be determined either by direct frequency measurement or by period averaging. The time period of measurement will normally lie in the range of 0,1 s to 1 0 s. Period averaging will generally be used for the measurement of frequencies less than 5 MHz.