Anritsu Company

Vincent W C Wong

William W Oldfield

Kenneth C Harvey

Chris Turl

A power meter includes components to measure RMS power over an 84 dB range or greater using the I-V square-law relation of a diode for measurements. The power meter includes multiple diodes along with a power distribution manifold which includes power dividers to distribute an input signal to the diodes. In one embodiment, a first power divider ( ) distributes power to a first one of the diodes ( ), and to the second power divider ( ) which distributes power to the second ( ) and third ( ) diodes. The first power divider ( ) is connected without attenuation to the first diode ( ). The second power divider ( ) is connected to the second diode ( ) through a 11 dB attenuator ( ), and to the third diode ( ) through a 28 dB attenuator ( ). With such attenuation, the first diode can operate in its square law range for measurements of signals with power from &minus;64 dBm to &minus;14 dBm, while the second diode can operate in its square law range for signals with power from &minus;14 dBm to &plus;3 dBm, and the third diode can operate within its square law range for signals with power from &plus;3 dBm to &plus;20 dBm. By measuring the current from the appropriate diode depending on the power level of the input signal, RMS power can be determined accurately over an 84 dB operating range. In an alternative embodiment, unequal power dividers ( ) and ( ) are used to distribute power and eliminate the need for attenuators ( ) and ( ) and to provide greater operating range sensitivity.

RMS power sensor with 84 dB dynamic range

A power meter includes components to measure RMS power over an 84 dB range or greater using the I-V square-law relation of a diode for measurements. The power meter includes multiple diodes along with a power distribution manifold which includes power dividers to distribute an input signal to the diodes. In one embodiment, a first power divider (,) distributes power to a first one of the diodes (,), and to the second power divider (,) which distributes power to the second (,) and third (,) diodes. The first power divider (,) is connected without attenuation to the first diode (,). The second power divider (,) is connected to the second diode (,) through a 11 dB attenuator (,), and to the third diode (,) through a 28 dB attenuator (,). With such attenuation, the first diode can operate in its square law range for measurements of signals with power from &minus;64 dBm to &minus;14 dBm, while the second diode can operate in its square law range for signals with power from &minus;14 dBm to &plus;3 dBm, and the third diode can operate within its square law range for signals with power from &plus;3 dBm to &plus;20 dBm. By measuring the current from the appropriate diode depending on the power level of the input signal, RMS power can be determined accurately over an 84 dB operating range. In an alternative embodiment, unequal power dividers (,) and (,) are used to distribute power and eliminate the need for attenuators (,) and (,) and to provide greater operating range sensitivity.

A dual mode power meter provides a first operation mode in the square law operating range of the diode, and a second mode in the square law region as well as the transition and linear operating ranges of the diode. The power meter includes multiple diodes. A manifold made up of power dividers distributes a signal input to the power meter to the diodes. A different attenuation is provided to each diode so that the square law operating range for each diode covers a different power range. By selecting the appropriate diode output for power measurements in the first mode, the overall square law operating range for the power meter will be greater than a power meter using a single diode. The power meter further includes a memory map of voltage vs. power in the square law, transition and linear regions of a diode measured for an unmodulated CW input for the second operation mode. The map of voltage vs. power enables power to be measured faster in the second mode for unmodulated CW signals provided to the power meter which are beyond the square law operating region for the diodes of the power meter.

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Morgan Hill, CA, United States of America

Vincent W C Wong