LECTURE 12

Question 1

• Produces electrical voltage.
• Voltage drives transducer to produce sound pulse.
• Tells receiver and memory contact made.
• Starts timer for “time of flight” to calculate depth.

Answer 1

THE PULSER AKA BEAM FORMER!!!

Question 2

PULSER FUNCTIONS:

Answer 2

• Controls PRF, PRP, Amplitude of pulse, frequency for CW and firing patterns for arrays.
• Controls acoustic power of machine.

Question 3

ACOUSTIC POWER AKA:

Answer 3

OUTPUT POWER, TRANSMIT OR OUTPUT, ENERGY OUTPUT, OUTPUT GAIN.

Question 4

• CONVERTS US TO ELECTRICAL VOLTAGE AND ELECTRICAL VOLTAGE TO US.
• SENDS INFO FROM VOLTAGE TO RECEIVER.

Answer 4

TRANSDUCER

Question 5

5 FUNCTIONS OF THE RECEIVER:

Answer 5

1. AMPLIFICATION
2. COMPENSATION
3. COMPRESSION
4. DEMODULATION
5. REJECTION

Question 6

CLIPS LARGE VOLTAGE SPIKES OR AMPLIFIES VERY WEAK SIGNALS.

Answer 6

PREAMPLIFIER

Question 7

• SONOGRAPHER CONTROLS BY ADJUSTING GAIN.

- SMALL VOLTAGES BOOSTED TO MAKE STRONGER.

Answer 7

AMPLIFICATION

Question 8

COMPENSATION AKA:

Answer 8

SWEPT GAIN
TIME GAIN COMPENSATION (TGC)
DEPTH GAIN COMPENSATION (DGC)
LGC
SGC

Question 9

COMPENSATION FUNCTIONS:

Answer 9

• CREATE UNIFORM IMAGE BRIGHTNESS.

- CAN BE ADJUSTED BY SONOGRAPHER/W TGC SLOPE.

Question 10

• SQUEEZING SIGNAL AMPLITUDES INTO A NARROWER RANGE.
• RATIO OF GREATEST TO SMALLEST AMPLITUDE THAT CAN BE HANDLED BY US INSTRUMENT.
• SOME DEGREE OF CONTROL.

Answer 10

COMPRESSION!!!

-DYNAMIC RANGE (LOG COMPRESSION, COMPRESSION) RELATES TO COMPRESSION.

LOWER DYNAMIC RANGE = HIGHER CONTRAST
HIGHER DYNAMIC RANGE = LOWER CONTRAST

Question 11

LARGEST - SMALLEST DYNAMIC RANGE:

Answer 11

1. TRANSDUCER/RECEIVER = 100-200 dB
2. MEMORY = 40-45 dB
3. MONITOR/HARD COPY = 20-30dB

Question 12

• PROCESS OF CHANGING VOLTAGES TO ANOTHER FORM.
• NOT USER ADJUSTABLE!!!
• 2 PARTS : RECTIFICATION, SMOOTHING

Answer 12

DEMODULATION

Question 13

WHAT IS RECTIFICATION AND SMOOTHING?

Answer 13

RECTIFICATION: NEG SIGNALS TO POS.

SMOOTHING: NEW SIGNAL IS AVERAGED.

Question 14

• PROCESS OF SUPPRESSING OR ELIMINATING SMALL VOLTAGE AMPLITUDES.
• HELPS REDUCE NOISE.
• SONOGRAPHER CONTROLS.

Answer 14

REJECTION!!!

-CONTROLLED WITH FILTER CONTROL.

Question 15

REJECTION AKA:

Answer 15

SUPRESSION
THRESHOLD
FILTER

Question 16

OVERALL RECEIVER FUNCTION:

Answer 16

MANIPULATES AND PROCESSES VOLTAGES AND SENDS THEM TO MEMORY (SCAN CONVERTER)