text: referring now to fig5 , a system and method for reducing the number of connections to an integrated transmitter will be described . one way to reducing the number of connections to an integrated transmitter may be to integrate logic circuitry to control the three inputs : pin , nin , and rtzin . fig5 shows a block diagram of one embodiment of the present invention using serial shift registers and latches to store the digital pattern for each of the three inputs . the transmitter 10 may consists of three serial shift registers 12 a - 12 c and a latch 14 . in the embodiment shown in fig5 , the shift registers 12 a - 12 c may be 32 - bit shift registers while the latch 14 may be a 96 bit latch . the latch 14 may be used to hold the data for pin , nin and rtzin . in the present embodiment , the 96 - bit latch 14 holds 32 - bits of data for pin 12 a , 32 - bits of data for nin 12 b , and 32 - bits of data for rtzin 12 c . the three serial shift registers 12 a - 12 c may share a common clock pin , clk . the data in the shift registers 12 a - 12 c may be shifted during low to high clock transition . once the data for the latch 14 is stored , it may be transferred to the three serial shift registers 12 a - 12 c when the enable logic input , en , detects a low to high transition . the outputs of each serial shift registers 12 a - 12 c generate the desired pin , nin , and rtzin signals respectively . this eliminates the need for having external connections for pin , nin , and rtzin . the data in the serial shift register 12 a - 12 c may be shifted out via the clock pin when the en pin is high . with the desired data loaded in the serial shift registers 12 a - 12 c , the tx output waveform on fig3 may be executed with a single input control , en and a clock signal , clk . this is shown in fig6 . the programmable serial shift register approach results in an arbitrary pattern generator because it may allow for any digital pattern to be created . some more simplified systems may have just a few fixed patterns so programmability in these situations is optional . alternative methods of the present invention may be to replace the programmable pattern generator with fixed predetermined patterns . another method of the present invention may be to replace the serial shift registers with programmable state machines . yet , another method of the present invention may be to replace the serial shift registers with small programmable counter that counts how many cycles the transmitter output will send out . once completed , it can end with a return to zero . each channel has its own clock signal to push the data out of the serial shift registers 12 a - 12 c . each clock line has its own delay time to allow the system to do beamforming . it may be considered as an acoustic lens and the curvature due to the delay times performs the focusing . 128 clock signals are needed in the present embodiment . the output frequency is controlled by adjusting the clock frequency . the number of logic inputs per transmitter is reduced from three to one . referring now to fig7 , one embodiment of an ultrasound transmitter system 100 is shown . in the present embodiment , the system 100 is a 128 channel system that reduces the number of control lines from three to one . the block 110 labeled logic pattern for hvout may be the serial shift registers 12 a - 12 c shown in fig5 . the blocks 112 labeled high voltage mosfets may be the p 1 , p 2 , n 1 , n 2 and the two diodes d 1 and d 2 shown in fig5 . the number of control lines can be further reduced by integrating a programmable time delay and a programmable frequency divider to generate the desired clock signals for each transmitter output . fig8 shows the schematic of a single channel 200 of the present invention with a programmable time delay and frequency divider circuit integrated . a counter 202 may be used for a time delay . in the present embodiment , a 10 - bit counter may be used . latches 204 may be used to program and store the data for the counter 202 . input osc - in can be used as the clock input for the counter 202 . a divide by n frequency divider 206 may also be used . the frequency divider 206 may be used to divide the osc - in frequency by n . the value for n may also be programmable and may be stored in the latch 204 . the frequency divider 206 sets the clock frequency for the serial shift registers 212 a - 212 c . once the trigger input is activated , the stored data for the delay counters 202 , frequency divider 206 , and output patterns may be loaded . the counter 202 may start counting down and the frequency divider 206 may divide the osc - in frequency by n . once the counter counts down to zero , the clock signal may be applied to the three serial shift registers 212 a - 212 c thereby generating the appropriate pin , nin , and rtzin signals . referring now to fig9 , a block diagram of a 128 channel system 300 of the present invention is shown . the system 300 reduces the number of control lines per system to just a single input trigger . the block 310 labeled logic pattern for hvout may be the serial shift registers 12 a - 12 c shown in fig5 . the block labeled high voltage mosfets 312 may be the p 1 , p 2 , n 1 , n 2 and the two diodes d 1 , d 2 shown in fig5 . referring now to fig1 , the waveforms for the system with 128 transmitter channels with integrated programmable time delay is shown . the 128 enable inputs may be replaced with two logic input pins , trigger and osc - in as shown in fig8 and 9 . the topology of the present invention is independent of system channel . for example , a system requiring 256 channel may only need a single trigger pin to activate all 256 channels . the objective of the present invention of reducing the number of control lines for the transmitter has been achieved . the present invention is not limited to just 3 - level outputs . the present invention can be extended to 2 - level outputs , 5 - level outputs , and 7 - level outputs . the output stage for a 2 - level and 3 - levels are shown in fig1 a and 11b . the number two for 2 - levels represents two active transistors to set the output to two different voltage levels . in this case , it is active device p 1 to set the output to vpp 1 and n 1 to set the output to vnn 1 . to provide a few examples , for vpp 1 =+ 150v and vnn 1 = 0v , the output can swing from 0v to + 150v . as a second example , for vpp 1 = 0v and vnn 1 =− 150v , the output can swing from − 150v to 0v . for a third example , vpp 1 =+ 75v and vnn 1 =− 75v , the output can swing from − 75v to + 75v with a slow decay to 0v from resistor r . the 2 - level transmitter will only need 2 sets of serial shift registers as compared to 3 sets for the 3 - level transmitter . 2 - level transmitter serves a lower end ultrasound market segment where performance versus cost is traded off . the outputs for 5 - levels and 7 - levels outputs are shown in fig1 a - 12b . the 5 - level and 7 - level serve the higher end ultrasound machines . additional shift registers will be required for the additional levels . the implementation is the same as the 3 - level transmitter . the reduction on control pins of the present invention will benefit the whole market segment from low end to high end . while embodiments of the disclosure have been described in terms of various specific embodiments , those skilled in the art will recognize that the embodiments of the disclosure can be practiced with modifications within the spirit and scope of the claims .