A signal processing module for a measurement instrument , comprising an analysis module , a measurement input , and at least two parallel measurement channels , wherein the at least two parallel measurement channels are each connected to the measurement input , such that an input signal received via the measurement input is forwarded to the two parallel measurement channels , wherein a first one of the at least two parallel measurement channels is configured to process the input signal, thereby generating a first complex-valued measurement signal, wherein a second one of the at least two parallel measurement channels is configured to process the input signal, thereby generating a second complex-valued measurement signal, wherein the analysis module is configured to determine a first error quantity associated with the first complex-valued measurement signal, wherein the analysis module is configured to determine a second error quantity associated with the second complex-valued measurement signal, wherein the analysis module is configured to determine a complex-valued average signal, wherein the complex-valued average signal corresponds to a combined average of the first complex-valued measurement signal and of a complex conjugate of the second complex-valued measurement signal, wherein the analysis module is configured to determine a combined error quantity based on the complex-valued average signal, and wherein the analysis module is configured to determine a comparison quantity based on the combined error quantity as well as based on the first error quantity and/or the second error quantity, wherein the comparison quantity is indicative of a relative magnitude of the combined error quantity compared to the first error quantity and/or the second error quantity. wherein the at least two parallel measurement channels are each connected to the measurement input , such that an input signal received via the measurement input is forwarded to the two parallel measurement channels , wherein a first one of the at least two parallel measurement channels is configured to process the input signal, thereby generating a first complex-valued measurement signal, wherein a second one of the at least two parallel measurement channels is configured to process the input signal, thereby generating a second complex-valued measurement signal, wherein the analysis module is configured to determine a first error quantity associated with the first complex-valued measurement signal, wherein the analysis module is configured to determine a second error quantity associated with the second complex-valued measurement signal, wherein the analysis module is configured to determine a complex-valued average signal, wherein the complex-valued average signal corresponds to a combined average of the first complex-valued measurement signal and of a complex conjugate of the second complex-valued measurement signal, wherein the analysis module is configured to determine a combined error quantity based on the complex-valued average signal, and wherein the analysis module is configured to determine a comparison quantity based on the combined error quantity as well as based on the first error quantity and/or the second error quantity, wherein the comparison quantity is indicative of a relative magnitude of the combined error quantity compared to the first error quantity and/or the second error quantity. <EOS>