PureView™ Pulser-Receiver Operator Manual
Page 17
Imaginant Inc.
The PureView red status indicator ‘Pulse’ LED will illuminate to indicate that the pulser is being
triggered. Enable the pulser power supply to produce transducer excitation pulses on the T/R
connector. Adjust the frequency of pulser firing such that all echoes from one excitation pulse
have subsided before a new excitation pulse is generated.
Adjust the Damping and Energy controls to obtain the desired excitation pulse characteristics.
Adjust the receiver gain control so that signals of interest (signals from the PureView Output
connector) do not exceed the range of +500mV to - 500mV into a 50
termination.
Adjust the high and low pass filter cutoff frequencies (as desired). The High pass filters can be used
to eliminate low-frequency energy from signals of interest. The low pass filter can be used to
reduce the receiver bandwidth and improve the signal to noise ratio.
IMORTANT NOTE - The PureView receiver contains circuitry to protect its receiver from the large transducer
excitation pulse. The operation of this protection circuit causes two short pulses to appear in the receiver
Output signal, and these pulses bracket the time when the pulser ‘fires’. The first short pulse occurs
approximately 70ns after the rising edge of the Trig / Sync signal. The second short pulse follows the first by
300ns or more (depending on the PureView model).
The Receiver Output signal will not provide any ultrasound signals from its T/R or Through inputs during the
interval of time between these two short pulses. During this interval the Receiver Output waveform contains
no meaningful signal content. Although the two short pulses may look similar to ultrasound signals, neither
of these short pulses is representative of any signals produced by the transducer(s) during that interval.
An example of the receiver-protection pulses is shown below. This is the output of a PureView unit where
the horizontal time scale is 100ns / major division. The purple trace is the PureView Trig / Sync pulse. The
blue trace is the Receiver Output signal with the Receiver gain set to 20dB. The two short pulses in the (blue)
Receiver Output waveform follow the rising edge of the (purple) Trig / Sync pulse by 70ns and 640ns
respectively. The exact timing of these pulses is PureView model dependent and the second pulse may
appear earlier or later in time than what is shown, depending on the model. In some low frequency
PureView models, the second pulse may occur up to 1.2us after the rising edge of the Trig / Sync signal.