The HP Model 5382A Frequency Counter (see Figure 1-1) is a direct-counting frequency counter that has a range of 10 Hz to 225 MHz. Eight display digits are provided. Front-panel controls allow a selection of gate times and attenuation factors of the input signal. A rear-panel connector and associated selector switch allow connection of an external time base oscillator. This feature also allows ratio measurements to be made by the counter. When the optional temperature compensated crystal oscillator is included (Option 001), the switch is not provided and the connector allows external use of the 10 MHz time base oscillator. Refer to Table 1-1 for all counter specifications.