TL852

SONAR RANGING RECEIVER

SLSS003 − SEPTEMBER 1983 − REVISED MARCH 1988

4

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

POST OFFICE BOX 1443

• HOUSTON, TEXAS 77251−1443

APPLICATION INFORMATION

detect level versus gain step

Detect level is measured by applying a 15-cycle burst of 49.4 kHz square wave just after the beginning of the

gain step to be tested. The least burst amplitude that makes REC reach the trip level is defined to be the detect

level. System gain is then inversely proportional to detect level. See the test circuit in Figure 1.

490 k

Ω

5 k

Ω

5 k

Ω

R1

0.01

µF

0.0022

µF

21 mH

500 pF

0.01

µF

L1

1 mH

8

7

6

5

4

3

2

1

VCC

1000 pF

Trip

Level

Detect

15-Cycle

49.4-kHz

Variable-Amplitude

Burst Generator

68 k

Ω

9

10

11

12

13

14

15

16

BIAS

G2IN

G1OUT

VCC

LC

GADJ

XIN

G1IN

REC

NC

NC

GCC

GCB

GCA

GCD

GND

TL331

15 Pulses

Trip Level

Input

Signal

Rec

Output

Comparator

Output

All Resistors

±1%, 1/4 W

All Capacitors

±1%, Film

L1 Q > 60 at 50 kHz

C1 Q > 500 at 50 kHz

Figure 1. Detect-Level Measurement Circuit and Waveforms