MV5087 Ver la hoja de datos (PDF) - Unspecified

Número de pieza

componentes Descripción

Fabricante

MV5087

DTMF GENERATOR

Unspecified 

MV5087

OUTPUT FREQUENCY

Table 1 shows the output frequency deviation from the

standard DTMF frequencies when a 3.58MHz crystal is used

as the reference.

The row and column output waveforms are digitally

synthesised using R-2R D-to-A converters (see Fig.6),

resulting in a ‘staircase’ approximation to a sinewave. An

opamp mixes these tones to produce a dual-tone waveform.

Single tone distortion is typically better than 7% and all

distortion components of the mixed dual-tone should be 30dB

relative to the strongest fundamental (column tone).

Standard

DTMF

(Hz)

Row

Column

f1 697

f2 770

f3 852

f4 941

f5 1209

f6 1336

f7 1477

f8 1633

Tone Output

Frequency Using

3.5795545 MHz

Crystal

701.3

771.4

857.2

935.1

1215.9

1331.7

1471.9

1645.0

% Deviation

from Standard

+0.62

+0.19

+0.61

-0.63

+0.57

-0.32

-0.35

+0.73

Low

Group

High

Group

Table 1: Output frequency deviation

VOUT

a)

t

VOUT

b)

t

Figure 6: Typical sinewave output (a) Row tones (b) Column tones

DISTORTION MEASUREMENTS

THD for the single tone is defined by:

100 (

V2 + V2 + V2 + ---- V2 ) %

2f 3f 4f

nf

V fundamental

Where V2f --- Vnf are the Fourier components of the waveform.

THD for the dual tone is defined by:

100 (

V2 + V2 + V2 + V2 + V2 --- V2 + V2 )

2R 3R nR 2C 3C

nc IMD

V2 + V2

ROW

COL

where

VROW is the row fundamental amplitude

VCOL is the column fundamental amplitude

V2R—VnR are the Fourier component amplitudes of the row frequencies

V2C—VnC are the Fourier component amplitudes of the column frequencies

VIMD is the sum of all intermodulation components.

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