Input sensing using overlapping code division multiplexing (CDM)

An input device for sensing a biometric object, the input device comprising:

• a surface corresponding to a sensing region, wherein the sensing region is configured to receive one or more inputs;
• transmitters, configured to be driven with transmitter signals;
• and
• receivers, configured to obtain measurement signals corresponding to the one or more inputs, by:
• driving a first subset of the transmitters according to multiple drive iterations of a first sub-matrix of a CDM drive matrix, wherein the CDM matrix is a zero row sum matrix, and obtaining first measurement signals with the receivers, and thereafter driving a second subset of the transmitters according to multiple drive iterations of a second sub-matrix of the CDM drive matrix, wherein the first subset of transmitters driven according to the multiple drive iterations of the first submatrix and the second subset of transmitters driven according to the multiple drive iterations of the second submatrix include different transmitters and at least one transmitter in common, and obtaining second measurement signals with the receivers.

A non-transitory computer-readable medium having processor-executable instructions stored thereon for performing input sensing using an input device, the processor-executable instructions, when executed by a processing system, enable the processing system to implement the following method:

• obtaining, via receivers of the input device, measurement signals corresponding to one or more inputs received at a sensing region of the input device, wherein obtaining the measurement signals comprises:
• driving a first subset of transmitters of the input device according to multiple drive iterations of a first sub-matrix of a CDM drive matrix, wherein the CDM matrix is a zero row sum matrix, and obtaining first measurement signals with the receivers, and driving a second subset of the transmitters according to multiple drive iterations of a second sub-matrix of the CDM drive matrix, wherein the first subset of transmitters driven according to the multiple drive iterations of the first submatrix and the second subset of transmitters driven according to the multiple drive iterations of the second submatrix include different transmitters and at least one transmitter in common, and obtaining second measurement signals with the receivers;
• and
• generating an image of the one or more inputs by processing the first measurement signals and the second measurement signals.