Telecommunications – Transmitter – Power control – power supply – or bias voltage supply
Reexamination Certificate
2000-03-03
2003-04-15
Urban, Edward F. (Department: 2685)
Telecommunications
Transmitter
Power control, power supply, or bias voltage supply
C455S075000
Reexamination Certificate
active
06549761
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a radio frequency processing apparatus of a wideband wireless local loop (W-WLL), and more particularly, to a radio frequency transmission control apparatus for preventing oscillation in a W-WLL terminal, in which power supply is controlled in accordance with characteristics of each active element of radio frequency transmitter unit in the W-WLL terminal, to thereby eliminate an oscillation caused by a simultaneous power supply to the radio frequency processing apparatus and minimize power consumption.
2. Description of the Related Art
FIG. 1
is a block diagram illustrating a radio frequency processing apparatus of a common W-WLL terminal.
Referring to
FIG. 1
, the radio frequency processing apparatus includes a radio frequency receiving unit
20
for demodulating an WLL radio frequency band signal received via an antenna to a baseband signal so as to be processed in a modem; a radio frequency transmitting unit
40
for modulating the baseband signal to a WLL radio frequency band signal and transmitting the modulated signal via an antenna; a local clock generating unit
30
for generating a local clock to be used in the radio frequency receiving unit
20
and radio frequency transmitting unit
40
; and a BBM (baseband module) interface unit
50
for matching among a BBM for performing a signal processing in a W-WLL terminal, the radio frequency receiving unit
20
and radio frequency transmitting unit
40
.
Referring to
FIG. 2
, the radio frequency receiving unit
20
further includes a power switch unit (VCC switch unit)
60
for controlling a power supply to operate the radio frequency receiving unit
20
in accordance with a control of the BBM interface unit
50
; an LNA (low noise amplifier)
20
a
for reducing a noise in a signal output from an antenna duplex
10
and amplifying the noise-reduced signal; an RF BPF (radio frequency band pass filter)
20
b
for performing a band pass filtering to a radio frequency signal output from the LNA
20
a
; an LNA
20
c
for performing a low-noise amplification to the signal that has passed the RF BPF
20
b
; an RF BPF
20
d
for performing a band pass filtering to the signal that has passed the LNA
20
c
; a down-mixer
20
e
for mixing up the local clock generated from the local clock generating unit
30
and the signal that has passed the RF BPF
20
d
and generating an IF (intermediate frequency); an IF BPF (intermediate frequency radio frequency band pass filter)
20
f
for performing a band pass filtering to the signal that has passed the down-mixer
20
e
; an automatic gain control amplifier AGC IF
20
g
for converting an automatic control voltage in accordance with a level of the signal output from the IF BPF
20
f
so as to maintain an output signal at a regular level; an adder
20
j
for generating an automatic control voltage so as to maintain a signal output from the modem of W-WLL terminal at a regular level and providing the AGC IF
20
g
with thus-generated automatic control voltage; an IF amplifier
20
k
for amplifying a signal output from the AGC IF
20
g
; a demodulator
201
for demodulating a signal output from the IF amplifier
20
k
using the local frequency output from the local clock generating unit
30
; and a data buffer
20
m
for buffering a signal output from the demodulator
201
and outputting the result to the BBM interface unit
50
.
Thus-configured radio frequency receiving unit of a common W-WLL terminal operates as follows.
The BBM (digital signal processing apparatus of W-WLL RIU (radio interface unit) outputs a control signal RX_ON for power supply of the radio frequency receiving unit
20
and a gain control PDM signal of the local clock generating unit
30
. Thus, the VCC switch unit
60
supplies power to each component constituting the radio frequency receiving unit
20
, and the local clock generating unit
30
generates a local RF and local IF.
A forward channel RF signal transmitted from a W-WLL radio port is received via an antenna and input to the antenna duplex
10
. Then, the antenna duplex
10
eliminates signals existing in an area excluding an applied bandwidth, and transmits the result to the LNA
20
a.
The LAN
20
a
amplifies the signal according to a supporting standard, and transmits the result to the RF BPF
20
b
. The RF BPF
20
b
has a bandwidth of 30 MHz, filters only a signal of bandwidth of 30 MHz, and transmits the result to the LNA
20
c
. The LNA
20
c
reduces noise of the input signal, amplifies the same, and transmits the same to the RF BPF
20
d
. The RF BPF
20
d
performs a filtering to enhance a noise figure, and outputs the result to the down-mixer
20
e.
The down-mixer
20
e
receives local RF (radio frequency higher than the received RF by the amount of IF) output from the RF VCO (voltage-controller oscillator)
30
c
of the local clock generating unit
30
, and mixes the local RF with the signal output from the RF BPF
20
d
, to thereby generate an intermediate frequency (IF). This IF is for a conversion to a baseband.
The IF BPF
20
f
passes, among IFs output from the down-mixer
20
e
, only the bandwidth corresponding to the band of the processed signal of a modem of W-WLL terminal, and suppresses signals existing outside of the band and in the adjacent channel.
The AGC IF
20
g
has a unique gain control scope according to characteristics of component, and changes gain control voltage according to the input signal level, thus maintaining output signal at a regular level. The gain control signal is output from a modem.
The signal output from the AGC IF
20
g
is amplified in the IF amplifier
20
k
, and transmitted to the demodulator
20
l
. The demodulator
20
l
receives local IF output from the IF VCO
30
e
of the local clock generating unit
30
. Using such a local IF, output signal of the IF amplifier
20
k
is demodulated by a QPSK (quadrature phase shift keying) method. I-signal and Q-signal which are demodulated to a baseband are buffered in the data buffer
20
m
and output to the BBM interface unit
50
.
FIG. 3
illustrates configuration of a common radio frequency transmitting unit which operates as follows.
The radio frequency transmitting unit
40
modulates I-signal and Q-signal of the baseband transmitted from the BBM interface unit
50
to a QPSK signal, and converts the same to an RF signal using local RF signal and local IF signal. Then, the RF signal is amplified using a power amplifier
40
k
, and emitted via an antenna.
A power switch unit
70
of the radio frequency transmitting unit
40
supplies/cuts off power to/from each component of the radio frequency transmitting unit
40
in accordance with a power control signal output from the BBM interface unit
50
. That is, when TXON signal in a high-active state is output from the BBM interface unit
50
, the power switch unit
70
supplies power all over the active element of the radio frequency transmitting unit
40
through a single power supply line (TX_VCC) connected to the radio frequency transmitting unit
40
.
When each active element of the radio frequency transmitting unit
40
is thus-provided with a power through the line (TX_VCC), an overload problem may occur. Further, an additional problem may occur in that the radio frequency transmitting unit
40
outputs an undesired oscillation frequency while I-signal (TX_I) and Q-signal (TX_Q) output from the BBM interface unit
50
are transmitted to the power amplifier
40
k
, i.e., the final amplifier, via the data buffer
40
a
. That is, the radio frequency transmitting unit
40
has an oscillation when a power switching is performed, thus deteriorating Eb/No value of RF module transmitting output. In addition, such an oscillation may reduce capacity of the radio port when a wireless communication is performed.
During the delay time period until the transmitting signals are sequentially input from the data buffer
40
a
, that is, during the time period where the operation of the power amplifier
40
k
is not required, the power ampl
Bryan Cave LLP
Hyundai Electronics Industries Co,. Ltd.
Mehrpour Naghmeh
Urban Edward F.
LandOfFree
Radio frequency transmission control apparatus for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Radio frequency transmission control apparatus for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radio frequency transmission control apparatus for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3048945