With a built-in Rubidium atomic resonance-controlled frequency reference, these instruments are ideal for high-accuracy calibration procedures outside the calibration laboratory environment, such as in base station transmitters of large telecommunications networks like GSM.
The short warm-up time makes these frequency counters ready for use quickly, for example after transport or change of location inside a building. With a virtual clock frequency of 4 GHz, the PM 6685R frequency counters offer an unmatched resolution of 2.5 x 10-10 per second, giving 10 reliable read-out digits in only one or a few seconds. This makes high-accuracy calibration measurements possible, with the convenience of requiring only a digital counter.
The wide choice of input options allows digital calibration measurements at up to 8 GHz, without the complexity of needing to use synthesizers, mixers and filters to provide the required resolution down to the last digits.
Additionally, digital counting techniques allow a numerical offset or nulling of the display value to make it easy to read changing or arbitrary frequency values with many different digits.