Pulser-Receivers are comprised of the following functional components and controls which may be fully-integrated in a single enclosure, or split into separate Pulser and Receiver components:

 

 
 

Gain Stage

The Receiver's gain stage amplifies received ultrasound signals to an amplitude suitable for analysis.

Low-Pass Filter

The low-pass filter reduces the upper end of the Receiver's bandwidth to what is appropriate for the ultrasound signals, and improves the signal to noise ratio by reducing high frequency noise.

High-Pass Filter

The high-pass filter increases the lower end of the Receiver's bandwidth to remove undesired low-frequency content from received ultrasound signals. The high-pass filter also improves the rate at which the Receiver's output signal returns to zero following the transducer excitation pulse.

Pulser

The pulser circuit generates electrical impulses that are applied to a transducer causing the transducer to emit an ultrasound pulse.

PRF Control

The rate at which the pulser generates transducer-excitation pulses is referred to as the Pulse Repetition Frequency (PRF).  The pulser generates one pulse for each cycle of a trigger signal.  The PRF control sets the pulser to be triggered by an external source or by the instrument's internal PRF oscillator, and also sets the internal PRF oscillator frequency.  Note that a pulser has a defined maximum PRF, and triggering the pulser at rates above this maximum will result in reduced pulse amplitude and / or skipped pulses.

Pulse Energy

Pulser-Receivers may provide adjustable energy and adjustable voltage controls for the pulser. These controls allow the energy and amplitude of the transducer-excitation pulse to be adjusted to optimize the ultrasound signal generated by a transducer.

Transducer Damping

Pulser-Receivers may provide adjustable damping.  This allows the transducer's response to the transducer-excitation pulse to be altered through damping the resonant behavior of the transducer.

Interface

A Pulser-Receiver may be controlled by a host PC via a USB or Serial Port interface.

 

Pulser-Receivers can employ a single transducer that acts as both a transmitter and receiver.  This approach is referred to as the Pulse-Echo or Transmit-Receive mode of operation where the transducer generates an ultrasound pulse and then receives echoes. A Pulser-Receiver may also employ separate transmitting and receiving transducers in which a first transducer generates an ultrasound pulse, and a second transducer receives signals.  This approach referred to as the Through mode of operation. Regardless of how the pulser-receiver is configured, the receiver output signals are then acquired using a digital oscilloscope or a signal digitizer such as an A/D board in a PC.

 
Pulse-Echo Mode of Pulser-Receiver Operation
 
Through Mode of Pulser-Receiver Operation