ucb1300 NXP Semiconductors, ucb1300 Datasheet - Page 12

• Manufacturer Part Number: ucb1300
• Description: Advanced Modem/audio Analog Front-end
• Manufacturer: NXP Semiconductors

Philips Semiconductors
TELECOM CODEC
The telecom codec contains an input channel, built up from a 64 times oversampling sigma delta analog-to-digital
converter (ADC) with digital decimation filters, programmable attenuation gain and built-in sidetone suppression circuit.
The output path consist of a digital up-sample filter, a 64 times oversampling 4-bit digital-to-analog converter (DAC)
circuit followed by a differential output driver, capable of directly driving a 600
includes a mute function. The telecom codec also incorporates a loopback mode, in which codec output path and the
input path are connected in series.
The telecom sample rate (f
interface. The telecom sample rate is given by the following formula:
For example, a SIBCLK of 9.216 MHz, with a divisor of 40, results in a telecom sample rate of 7.2 kHz. Both the rising
and the falling edges of the SIBCLK are used in case TEL_DIV[n] is set to an odd number. In that case a 50% duty cycle
of the SIBCLK signal is mandatory to obtain time equidistant sampling.
The input path of the telecom codec has a programmable attenuation gain. It also implements a voice band filter, which
consists of a digital low pass filter, which is a part of the decimation filter. Therefore the pass band of the voice band filter
2000 Jun 26
TOUTP
TOUTN
Advanced modem/audio analog front-end
f
st
=
------------------------------------------------- -
64 TEL_DIV[n]
TINP
TINN
2 F
SIBCLK
TEL_SIDE_ENA
SUPPRESSION
SIDETONE
CIRCUIT
st
) is derived from the SIB interface clock pin (SIBCLK) and is programmable through the SIB
(15 < TEL_DIV[n] <128)
Fig.7 Telecom codec block diagram.
TEL_MUTE
12
TEL_ATTATT TEL_GAIN
4-bit DAC
isolation transformer. The output path
1-bit ADC
DIGITAL
DECIMATION
FILTER
DIGITAL
NOISE
SHAPER
Product specification
UCB1300
TEL_OUT_ENA
TEL_IN_ENA
14
14