and 107 respectively with pull up resistor 95 on signal coarse_start and pull up resistor 96 on signal coarse_end when signals enable_start and enable_end from pulse width and delay controller 99 are not enabled this will drive the tri state circuits 101 102 to a high impedance state and the outputs coarse_start and coarse_end are pulled high through pull up resistors 95 and 96 on the other hand when signals enable_start and enable_end are enabled this drives the output coarse_start and coarse_end to 0 to set the coarse width and delay of the excitation pulse the coarse_start and coarse_end falling edges can be several clock cycles apart depicted in fig2 or generated on the same clock edge as depicted in fig3 to produce a narrower excitation pulse resolution than the clock value allows the narrow excitation pulse width is required for high frequency transducers such as 125 mhz reference is still made to fig1 tri state circuits 101 and 102 allow for decoupling of the digital power supply to a low noise precision analog power supply 12 through the pull up resistors 95 and 96 on coarse_start and coarse_end signals thus eliminating the digital power supplies which may be noisy the low noise precision analog power supply 12 can be one of a precision voltage reference device which feeds all the remaining fine delay analog circuits 13 including pull ups 95 and 96 on coarse_start and coarse end a common low noise precision analog power supply 12 allows for more precise delay for finer adjustment through the analog circuits reference is now made primarily to fig1 assisted by referring to fig2 and 3 the digital.