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BEAM FORMER The beam former is where the action originates. It consists of a pulser, pulse delays, transmit/receive (T/R) switch, amplifiers, analog-to-digital converters, echo delays, and a summer ② & # A O Pulser (transmitter) The pulser generates the voltages that drive the tra...

BEAM FORMER The beam former is where the action originates. It consists of a pulser, pulse delays, transmit/receive (T/R) switch, amplifiers, analog-to-digital converters, echo delays, and a summer ② & # A O Pulser (transmitter) The pulser generates the voltages that drive the transducer. The greater the voltage amplitude produced by the pulser, the greater the amplitude and intensity of the ultrasound pulse produced by the transducer Determines the pulse repetition frequency, pulse repetition period, and pulse amplitude. Pulser (transmitter) Output level is sometimes shown on the display in terms of a percentage or decibels relative to maximum (100% or 0 dB) output Reduction of acoustic output reduces received echo amplitude. An increase in amplifier gain can compensate for this. A, The output indicator (arrow; AO = acoustic output) shows a percentage relative to the maximum (100% in this example). B-C, The output indicator here shows decibels relative to the maximum. An output of 0 dB (100%) is compared with one of -9 dB (12.5%), in which the weaker echoes produce a darker image Pulse Delays The pulse delays have a single input from the pulser but multiple outputs to the transducer elements The concept of pulse delays is integral to phased array transducers, where delays are accurately calculated to steer and focus the beam electronically, allowing for real-time adjustments to the beam's direction and focus without moving the transducer physically * A, A transmission channel consists of an independent - - delay and transducer element (E) combination. Several - - channels emanate from the pulser (P). B, A reception channel consists of an independent element (E), amplifier (AMP), analog-to-digital converter (ADC), and delay. The signals from many channels are combined in the summer (SUM).