A signal processing module for a measurement instrument, comprising an analysis module, a measurement input, and at least two parallel measurement channels (26, 28), wherein the at least two parallel measurement channels (26, 28) 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 (26, 28), wherein a first one of the at least two parallel measurement channels (26, 28) 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 (26, 28) 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 (26, 28) 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 (26, 28), wherein a first one of the at least two parallel measurement channels (26, 28) 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 (26, 28) 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.