Qubbe; Receiver (Rx) - Nokia 500 Service Manual

RM-750
System Module
Figure 40 Linko RF block diagram
The RF block uses RF ASIC N7512 that performs the RF back-end functions of receive and transmit function of
the cellular transceiver.

QuBBE

The front end module called QuBBE contains the needed front end filters and the switches. QuBBE contains:
• 3 duplexers (Band II, V, VIII)
• 1 triplexer (Band I, IV)
• 12 switches with the control
• Low and high band GSM TX low bass filters
• 50 ohms low and high and antenna interface
The control signals for the switches come from Älli.

Receiver (RX)

Linko RF has higher integration level compared to previous RF generations and especially more digital design
blocks have been integrated to Älli, RF Asic.
Älli contains the receiver chain from LNAs to digital base band interface. Digital RX baseband interface
contains four data and one clk signals. The data rate and clock frequency depend on the use case.
The main blocks in Älli are:
• LNAs: Balanced inputs for 850, 900, 1800, 1900, 2100 bands
• Passive mixer
• Analog baseband: Programmable for different modes
• ADC: Programmable Sigma Delta Modulator topology ADC
• RX Digital Front End (RXDFE): Contains for example digital filtering, DC offset compensation, wide/
narrowband power measurement blocks
There is integrated external LNA matching on the bands 900, 1800, 1900 and 2100. On 850 band, there is an
integrated matching.
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