EV6090 Datasheet, PDF (6/12 Pages) CML Microcircuits – ADVANCE INFORMATION

CVSD CODEC Evaluation Kit
6
EV6090 Evaluation Kit
3.1.2 Connect external regulated power supply.
• Adjust the supply for 5.0V
• Connect the positive lead from the power supply to “VDDIN” (P3:2) and the negative lead to “GND”
(P3:3).
3.1.3 Set Mode of Operation
To begin EV6090 operation, set switches S1-C1 (“CLKMODE1”) to OFF and S1-C2 (“CLKMODE2”) to ON to
enable 32kbps sampling mode. Next, ensure that switch S1-C3 (“ALGORITHM”) is set to OFF to enable the
3-bit algorithm. Alternatively, change S1 switch position C1 and C2 as shown in Table 1 for other sample
rates.
3.1.4 Quick Test
Connect handset and apply power. Adjust R6 clockwise to increase microphone audio level. Adjust R31
counterclockwise to increase audio level in the ear piece.
3.1.5 Further experimentation
Other modes of operation are available for test. Forced idle channel mode of either the encoder or decoder
can be realized by changing dip switch settings. The use of Table 1, coupled with a review of the CMX639
data bulletin, will allow the user to exercise all operating modes.
3.2 Adjustments
R6 - adjust audio input level to the CODEC.
R31 - adjust level for both the telephone hand set and speaker volume.
3.3 Operation
Jumpers E3 and E4 allow for different audio input and output routing.
For testing with audio signals applied at the “AUDIO IN” jack, jumper E13 should be removed to avoid having
undesired amplified signals injected into the encoder input.
For testing with audio signals supplied by either the microphone input or the telephone handset, jumper E13
should be installed. Due to the high gain nature of this signal path, however, R6 doesn't need to be adjusted
>0dB.
3.3.1 E3 Audio Input routing (to the CVSD encoder)
Jumper position 1 to 2 enables the following:
• RCA Audio input - RC1
• Mic Input – J3
• Telephone Hand set input – J2
Jumper position 2 to 3 enables the following
• Screw Terminal strip P2:1 input
3.3.2 E4 Audio output routing (from the CVSD decoder)
Jumper position 1 to 2 enables output audio to the following:
• RCA Audio output – RC2
• Screw Terminal strip P2:3 output
Jumper position 2 to 3 enables output audio to the following:
• Telephone Hand set output – J2
• Speaker output J4
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