RCVDL56DPFL/SP, RCV56DPFL/SP, and RCV336DPFL/SP Designer’s Guide
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1-3
1.3 TECHNICAL DESCRIPTION
Configurations and Rates
The selectable MDP configurations, signaling rates, and data rates are listed in Table 1-2.
Automatic Mode Selection
When automatic mode selection (AMS) is enabled, the MDP configures itself to the highest compatible data rate supported
by the remote modem (AUTO bit). Automode operation is supported in K56flex, V.34, V.32 bis, V.32 V.22 bis, V.22, V.21,
V.23, Bell 212A, and Bell 103 modes.
NOTE: Bit names refer to data, control, and/or status bits in the MDP interface memory (see Table 3-1).
Automatic Rate Adaption (ARA)
In K56flex, V.34, and V.32 bis modes, automatic rate adaption (ARA) can be enabled to select the highest data rate possible
based on the measured eye quality monitor (EQM) (EARC bit). This selection occurs during handshake/retrain and rate
renegotiation.
Tone Generation
The MDP can generate single or dual voice-band tones from 0 Hz to 3600 Hz with a resolution of 0.15 Hz and an accuracy
of ± 0.01%. Tones over 3000 Hz are attenuated. DTMF tone generation allows the MDP to operate as a programmable
DTMF dialer.
Data Encoding
The data encoding conforms to ITU-T recommendations V.34, V.32 bis, V.32, V.17, V.33, V.29, V.27 ter, V.22 bis, V.22,
V.23, or V.21, and is compatible with Bell 208, 212A, or 103, depending on the configuration.
Transmitted Data Spectrum
The transmitter spectrum is shaped by raised cosine filter functions as follows:
Configuration
Raised Cosine Filter Function
V.34, V.32 bis, V.32, V.17, V.33, V.29
Square root of 12.5%
V.27 ter, Bell 208
Square root of 50%
V.22 bis/V.22, Bell 212A
Square root of 75%
RTS – CTS Response Time
The response times of CTS relative to a corresponding transition of RTS are listed Table 1-3.
Transmit Level
The transmitter output level is selectable from 0 dBm to -15 dBm in 1 dB steps and is accurate to ±0.5 dB when used with an
external hybrid. The output level can also be fine tuned by changing a gain constant in MDP DSP RAM. The maximum
V.34/V.32 bis/V.32 transmit level for acceptable receive performance should not exceed –9 dBm.
Note: In V.34 mode, the transmit level may be automatically changed during the handshake. This automatic adjustment of
the transmit level may be disabled via a parameter in DSP RAM.
Transmitter Timing
Transmitter timing is selectable between internal (±0.01%), external, or slave.
Scrambler/Descrambler
A self-synchronizing scrambler/descrambler is used in accordance with the selected configuration.
Answer Tone
When the NV25 bit is a zero, the MDP generates a 2100 Hz answer tone at the beginning of the answer handshake for 5.0
seconds (V.8) or 3.6 seconds (V.32 bis, V.32, V.22 bis, V.22, V.23, and V.21). The answer tone has 180° phase reversals
every 0.45 second to disable network echo cancellers (V.8, V.32 bis, V.32). A superimposed PN + ID sequence is used to
identify K56flex when configured for V.8.
Summary of Contents for RC336DPFL
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