A measurement instrument adapted to measure mixed signals, comprising: a plurality of acquisition systems adapted to acquire the mixed signals; and a display system (42,18) adapted to display the mixed signals acquired by said acquisition systems; each of said acquisition systems including: an analog input interface (20,54) mounted on a panel of said measurement instrument adapted to receive an analog input signal; an analog-to-digital converter adapted to convert the analog input signal from said analog input interface to a digital signal: a logic input interface (62, 560-567) mounted on the panel of said measurement instrument and having N logic input terminals adapted to receive logic signals, wherein N is a positive integer; and N latch circuits adapted to latch the logic signals from said N logic input terminals respectively, characterised in that said digital signal is an N-bit digital signal, and each of said acquisition systems further comprises: a multiplexer adapted to select one of the N-bit digital signal from said analog-to-digital converter and the N logic signals from said N latch circuits; and a memory adapted to store the output from the multiplexer, wherein the memory is coupled to the display system; wherein in each of said acquisition systems said multiplexer is arranged to select the analog input signal when the analog input signal is applied to said analog input interface and said multiplexer is arranged to select the logic signals when a logic input signal is applied to said logic input interface. a plurality of acquisition systems adapted to acquire the mixed signals; and a display system (42,18) adapted to display the mixed signals acquired by said acquisition systems; each of said acquisition systems including: an analog input interface (20,54) mounted on a panel of said measurement instrument adapted to receive an analog input signal; an analog input interface (20,54) mounted on a panel of said measurement instrument adapted to receive an analog input signal; an analog-to-digital converter adapted to convert the analog input signal from said analog input interface to a digital signal: a logic input interface (62, 560-567) mounted on the panel of said measurement instrument and having N logic input terminals adapted to receive logic signals, wherein N is a positive integer; and N latch circuits adapted to latch the logic signals from said N logic input terminals respectively, a logic input interface (62, 560-567) mounted on the panel of said measurement instrument and having N logic input terminals adapted to receive logic signals, wherein N is a positive integer; and N latch circuits adapted to latch the logic signals from said N logic input terminals respectively, characterised in that said digital signal is an N-bit digital signal, and each of said acquisition systems further comprises: a multiplexer adapted to select one of the N-bit digital signal from said analog-to-digital converter and the N logic signals from said N latch circuits; and a memory adapted to store the output from the multiplexer, wherein the memory is coupled to the display system; a multiplexer adapted to select one of the N-bit digital signal from said analog-to-digital converter and the N logic signals from said N latch circuits; and a memory adapted to store the output from the multiplexer, wherein the memory is coupled to the display system; wherein in each of said acquisition systems said multiplexer is arranged to select the analog input signal when the analog input signal is applied to said analog input interface and said multiplexer is arranged to select the logic signals when a logic input signal is applied to said logic input interface.