17-08-2012, 03:01 PM
NXP Semiconductors
[attachment=31873]
Introduction
The TDA5051A is a complete ASK modem dedicated to data transmission on power line
network, requiring very few external components. It could be also used on any two-wire
network for exchanging informations by means of ASK carrier current technique (DC or
AC network).
The use of a digital structure for both transmission and reception part provides an efficient
solution for modulating and demodulating low baud rate data signals. A standard quartz
crystal is required to set the operation frequency; in transmission mode, it defines the
carrier frequency and in reception mode it defines the detection frequency.
Main features of the IC
• CMOS process IC: low power consumption, reliability and high temperature stability,
on-chip ESD protection
• Single +5 V power supply. The same power supply can be used to feed the
controller.
• On-chip clock circuit. Using an external quartz crystal, the oscillator sets the
operation frequency and the clock output pin gives the possibility to supply the clock
to a microcontroller. It is also possible to apply an external clock signal to the chip by
using one of the oscillator pins as an input.
• Full digital modulation with signal shaping. Using ROM and a 6-bit D/A converter
provides high stability of the carrier frequency, limitation of the signal bandwidth and
easy choice of the frequency within a large range.
• On-chip power amplifier with overload protection. Low distortion, low output
impedance amplifier for limiting the number of external components and the size of
the complete system. An internal feedback controls the output voltage to comply with
the EN50065-1 standard (122 dBV maximum (RMS)).
• Input amplifier with Automatic Gain Control (AGC). Provides a very high
sensitivity of 66 dBV (RMS), allowing the detection of small signals in heavily loaded
power line conditions.
• Digital narrowband filter with 8-bit A/D converter. Equivalent to an 8th-order
analog filter, for an accurate and sharp filtering of the input signal.
• Digital demodulation. A digital demodulator with variable threshold calculates the
optimum level in order to restore the baseband signal with the highest accuracy.
Modem output voltage
The maximum output voltage of a power line modem is also defined by the norm, and the
measurement of this voltage must be performed as described in the EN50065-1.
Basically, it consists of measuring, with a 50 spectrum analyzer, the carrier amplitude of
the complete system (modem + coupling network) on a standard load, called the
CISPR16 load.
Limiting conducted power line disturbances
One of the most important points of the EN50065-1 standard concerns the amplitude
limitation of non-expected harmonics outside the transmission band. To be officially
approved, this test requires specific equipment, but a measurement with a CISPR16
network and a 50 analyzer (resolution bandwidth of 9 kHz) can give a good idea of the
conducted disturbances.
Coupling with the power line
Introduction
The coupling network is the interface between the power line and the low voltage
TX_OUT and RX_IN pins of the modem. For low cost applications, when the insulation
with the mains is not required, a double LC network can be used, providing efficiency
without any adjustment or tunable components. When an insulation is mandatory, an
HF transformer should be used.
[attachment=31873]
Introduction
The TDA5051A is a complete ASK modem dedicated to data transmission on power line
network, requiring very few external components. It could be also used on any two-wire
network for exchanging informations by means of ASK carrier current technique (DC or
AC network).
The use of a digital structure for both transmission and reception part provides an efficient
solution for modulating and demodulating low baud rate data signals. A standard quartz
crystal is required to set the operation frequency; in transmission mode, it defines the
carrier frequency and in reception mode it defines the detection frequency.
Main features of the IC
• CMOS process IC: low power consumption, reliability and high temperature stability,
on-chip ESD protection
• Single +5 V power supply. The same power supply can be used to feed the
controller.
• On-chip clock circuit. Using an external quartz crystal, the oscillator sets the
operation frequency and the clock output pin gives the possibility to supply the clock
to a microcontroller. It is also possible to apply an external clock signal to the chip by
using one of the oscillator pins as an input.
• Full digital modulation with signal shaping. Using ROM and a 6-bit D/A converter
provides high stability of the carrier frequency, limitation of the signal bandwidth and
easy choice of the frequency within a large range.
• On-chip power amplifier with overload protection. Low distortion, low output
impedance amplifier for limiting the number of external components and the size of
the complete system. An internal feedback controls the output voltage to comply with
the EN50065-1 standard (122 dBV maximum (RMS)).
• Input amplifier with Automatic Gain Control (AGC). Provides a very high
sensitivity of 66 dBV (RMS), allowing the detection of small signals in heavily loaded
power line conditions.
• Digital narrowband filter with 8-bit A/D converter. Equivalent to an 8th-order
analog filter, for an accurate and sharp filtering of the input signal.
• Digital demodulation. A digital demodulator with variable threshold calculates the
optimum level in order to restore the baseband signal with the highest accuracy.
Modem output voltage
The maximum output voltage of a power line modem is also defined by the norm, and the
measurement of this voltage must be performed as described in the EN50065-1.
Basically, it consists of measuring, with a 50 spectrum analyzer, the carrier amplitude of
the complete system (modem + coupling network) on a standard load, called the
CISPR16 load.
Limiting conducted power line disturbances
One of the most important points of the EN50065-1 standard concerns the amplitude
limitation of non-expected harmonics outside the transmission band. To be officially
approved, this test requires specific equipment, but a measurement with a CISPR16
network and a 50 analyzer (resolution bandwidth of 9 kHz) can give a good idea of the
conducted disturbances.
Coupling with the power line
Introduction
The coupling network is the interface between the power line and the low voltage
TX_OUT and RX_IN pins of the modem. For low cost applications, when the insulation
with the mains is not required, a double LC network can be used, providing efficiency
without any adjustment or tunable components. When an insulation is mandatory, an
HF transformer should be used.