MAS9191A datasheet(20/36 Pages) MAS

20 / 36 page

DA9191A.000

July 31, 1997

FUNCTIONS

The gain of GC4 can be adjusted in the range -

0.67..+5.33dB with bits 0..3 in register 0AHEX. After

GC4 the signal is filtered with pre-emphasis filter

F10, which has a +6dB/octave (±1dB) frequency

response at the range 300Hz..3kHz. At 1kHz the

gain is 0dB. The pre-emphasis filter can be bypassed

with switch S14.The signal is then amplified with

GC5. Gain control GC5 is an SC-type with a

programmable gain adjustment. The range is 0dB..-

20 dB with 16 steps according to bits 0..3 in register

0AHEX.

At the output of GC5 is output pin LPFIN (or

highpass filter F9HP) and a SC-type limiter. The

limiting level is 439mVp and the tolerance is ±5%.

The 0dB level is 370mVp. The limiter can be

bypassed with switch S15. The lowpass filter F11

with a 6kHz notch follows the limiter. The gain of the

filter is 2.94dB at 1kHz. The filter and the limiter can

be bypassed with switch S16. GC6 and GC7 are

continuous time programmable gain adjustment

blocks. The gain of GC6 is -3dB ... +3dB with 16

step according to bits 0..3 in register 0BHEX. The gain

of GC7 is adjustable within - 3dB ... +1dB with bits

0..3 in register 0BHEX in 16 steps.

GC7 output is connected to pin TAUDOUT through

switch TXTST. The data transmission signal can be

examined at TAUDOUT with this switch. Also with

switch

TXTST,

the

performance

GC8,

3.75..3.75dB., F12 and F15 can be observed with an

input at TAUDIN. An external capacitor between pins

TADOUT and TAUDIN is required. The TAUDIN

input is connected to switch S19. The switch can be

used to mute the TX audio block. S19 is controlled

with bit 5 in register 01HEX. Switch S19 is also

controlled by the TX framing block. During data

transmission on the voice channel and with the

AUMUT bit in register 13HEX set to high the TX audio

block is muted with S19. Following S19 is a second

order lowpass filter F13 with 15kHz cutoff frequency.

After filtering the signal is summed with the data

signal and amplified with GC9. The gain of the

amplifier GC9 is adjustable with bits 0..3 located in

the range -3.0.. +3.0dB .The output of the amplifier

GC9 is then filtered with F14. The filter is a third

order lowpass filter with 54kHz cutoff frequency. The

gain at 1kHz is 0dB.

DTX bit of the regiter 0DHEX is used to set DATA,

DSAT and DST deviation. When the device is not in

DTX (Discontinous Transmission) the DTX = 0 and

there is nominal level at TX, 93 mVrms. If DTX is on,

the level is increased to 373 mVrms.

MAS9191A Datasheet(PDF) 20 Page - Micro Analog systems

MAS9191A Datasheet(HTML) 20 Page - Micro Analog systems

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

Datasheet Download

Link URL