Technical Field

The invention relates to a transmitter in terrestrial radio-television broadcasting, which saves energy and reduces failure by providing the best efficiency in all conditions and method of optimizing the transmitter efficiency.

Prior Art

At present, terrestrial transmitters are manufactured to operate at maximum efficiency at the frequency and power provided by the customer when they are produced. However, the customer may want to keep the power low or run it on another frequency while operating the transmitter. In this case, the efficiency of the transmitters decreases, and not only the excess energy is spent, but also malfunctions are increased.

Since the transmitter manufacturers produce transmitters according to the frequency and power information they receive from the customer, they have to repeatedly make tests during production, record the results and determine the values at the best efficiency rate. During these tests, it is necessary to trust that the person who performed the test is experienced and correctly performs the tests.

In the RF amplifiers of FM-TV transmitters, LDMOS transistors are used due to their efficiency, their high gain, their high power and their resistance to reflection. The efficiency of LDMOS transistors is most excellent at their maximum power. Besides, the efficiency of RF amplifiers varies according to frequency.

In the current technique, the power settings of terrestrial FM-TV transmitters are made by adjusting the supply voltages of the LDMOS RF transistors on the RF output amplifier stage, by changing the transistor bias voltage of the pre-amplifier stage in front of the RF output amplifier stage, or by changing the modulator output power. The transmitters are calibrated at the desired frequency and power values. This RF output amplifier adjusting the transmitter output power is provided through the control card, which adjusts the supply voltage or the modulator output power, and the output power is automatically reduced in cases such as temperature increase and reflected power increase, or the power supply output voltage is cut off and protection is performed. However, when the transmitter is operated at different values than the calibrated output frequency and/or output power, the temperature increase and consequently excessive energy consumption occur due to the decrease in the efficiency, and the malfunction rates increase as the transmitter moves away from the optimum operating values.

In the literature survey, an application no. TR 2005/02330 entitled “UTMS radio beacon equipment” was found. This application relates to a UMTS signal transmitter that can be easily transported, which is capable of transmitting a reference UMTS signal of known characteristics which can be received by different geographically dispersed terminals and which as a function of the received power and of the measured error rate, permits an estimate of the quality of the broadcast signal and the level of interference. The application does not mention a structure aimed at preventing malfunctions in using the transmitter outside the frequency and power range determined at the production stage.

As a result, due to the above-mentioned drawbacks and the inadequacy of the existing solutions, an improvement in the technical field has been required.

The Purpose of Invention

The invention is inspired by the current situation and aims to solve the problem above- mentioned.

The purpose of the invention is to eliminate problems that may occur if transmitters operate at a frequency and/or maximum output power different from the frequency and maximum output power calibrated in the factory.

Another purpose of the invention is to ensure that the calibration process is performed automatically to ensure that the transmitters operate at maximum efficiency.

The purpose of the invention is to make the tests of the amplifier stage safer utilizing software in the terrestrial FM radio/ TV transmitter manufacturing, to reduce the difficulties experienced by standardizing them, and to eliminate the need for experienced workers, and to enable the tests to be carried out in a very short time.

Another purpose of the invention is to reduce the malfunction rate as well as energy savings.

In order to fulfill the purposes described above, the invention is a transmitter used in the terrestrial radio-television broadcasting that automatically adjusts operating conditions in case of possible frequency change or low power operation, wherein; comprising

• a modulator with adjustable power,

• a power supply with adjustable voltage,

• a microprocessor that changes the power supply voltage within the voltage range determined by the operator and increases the input power with the modulator and when it reaches the targeted power, it multiplies the transistor current and voltage and records it in the RAM, and then operates the transmitter at that supply voltage and input power by choosing the one that will make the highest efficiency among these records.

The structural and characteristic features and all advantages of the invention outlined in the drawings below and in the detailed description made by referring these figures will be understood clearly, therefore the evaluation should be made by taking these figures and detailed explanation into consideration.

Brief Description of the Figures

Figure 1 Is a schematic view of the transmitter with increased efficiency of the invention.

Figure 2 Is the algorithm regarding the working principle of the transmitter with increased efficiency of the invention.

Figure 3 Is a block diagram showing the control of transmitters by adjusting the modulator power.

Figure 4 Is a block diagram showing the control of transmitters by adjusting the RF amplifier supply voltage.

Figure 5 Is a block diagram showing the control of transmitters by adjusting the modulator and amplifier.

Reference Numbers

A. Transmitter

1 . Button

2. Microprocessor 4. Display

5. Modulator

6. Power supply

7. RF amplifier

8. Preamplifier

9. Temperature sensor

10. Directional coupler

B. Method of optimizing transmitter efficiency

100. Initiate efficiency test.

101. Determination of the voltage range by entering the user's maximum and minimum test voltage values

102. Determination of the output power range by entering the user's maximum and minimum modulator output powers

103. Adjusting the modulator output power and voltage to a minimum

104. Checking whether there is an error in the minimum values entered

105. Writing an error message to the display

106. Checking whether the transmitter output power has reached the set transmitter limit value

107. Checking whether the voltage value reaches the maximum voltage value entered

108. Increasing the voltage value by 1 V

109. Increasing modulator output power by 1 dB

110. Checking whether the modulator output power reaches the maximum output power value entered

111. Checking whether the transmitter output power has reached the set transmitter limit value

112. Recording the efficiency, voltage and modulator output power values

113. Decreasing the voltage value by 1 V

114. Checking whether the voltage value reaches the minimum voltage value entered

115. Recording voltage and modulator output power values where the transmitter output power reaches the set limit value

116. Recording the voltage and modulator output power values for optimal efficiency

117. Recording maximum voltage and output power values 118. Initiate efficiency test manually

119. Finish the test

120. Frequency change made

121 . Output power change made

122. Yes

123. No

124. The method of optimizing transmitter efficiency is enabled

125. The method of optimizing transmitter efficiency is disabled

Detailed Description of the Invention

In this detailed description, preferred embodiments of the transmitter (A) with optimized efficiency and a method of optimizing transmitter efficiency (B) of the invention are explained only for a better understanding of the subject.

The efficiency of LDMOS transistors is most at the maximum powers. The RF amplifier (7) is the part that increases the power inside the transmitters (A). In other words, the modulator (5) gives 0.1 W RF power on a 1000 W transmitter (A), it is increased from 0.1 W to 10 W with an RF pre-amplifier, and it is increased from 10 W to 1000 W with an RF amplifier (7).

The transmitter of the invention, whose schematic view is given in Figure 1 , comprises a power supply (6) with which the voltage can be controlled and a modulator (5) whose power can be adjusted. With the buttons (1) on the transmitter (A), the operator determines the voltage range. When the microprocessor (2) reaches the targeted power by changing the voltage of the power supply (6) in the specified voltage range and increasing the input power with the modulator (5), the transistor multiplies the current and voltage; and then records it in RAM (3). In addition, the microprocessor (2) selects the one that will make the efficiency highest among these records, and the transmitter (A) is operated at that supply voltage and input power.

If the intended output power does not come out when the maximum input power is applied with the applied voltage, the microprocessor (2) does not evaluate that value. Therefore, the lowest value in the recorded values refers to the highest efficiency.

Efficiency = (RF Output Power/Power Consumed) ^* 100 (Formula 1)

The limit of frequency and RF output power is changed with the buttons (1) on the transmitter (A) and these values can also be tracked from the display (4) on the transmitter (A). These changes are detected by the microprocessor (2) and the algorithm is activated automatically or manually.

In order to measure the outgoing power in transmitters, i.e., the output power of the transmitter (A), by the microprocessor (2), the power outgoing is sampled via the directional coupler (10) and converted to DC (FWD is obtained) (Figure 3, Figure 4, Figure 5). An ADC table is created to determine which output corresponds to which DC value to be measured by the microprocessor (2).

Figure 2 shows the process steps for the method of optimizing transmitter efficiency (B) (Transmitter Self Management System) of the invention. When the frequency or output power limit is changed (120, 121), the method for optimizing the transmitter efficiency (B) works if it is enabled on the transmitter (A) control panel. In addition, the user can say that I do not want this algorithm to be activated automatically, I will manually do the most efficient working values at any time (118). The method of optimizing transmitter efficiency (B) works as follows: activation of initiate efficiency test manually (118) or automatically and initiation of the test (100), determination of the voltage range by entering the user's maximum (V TEST MAX) and minimum (V_TEST_MIN) test voltage values (101), determination of the output power range by entering the user's maximum (P TEST MAX) and minimum (P TEST MIN) modulator (5) output powers (102), adjusting the modulator (5) output power and voltage to a minimum (103), checking whether there is an error in the minimum values entered (104), if there is an error, writing the error message to the display (4) (105) on the transmitter (A) if there is no error, checking whether the output power (FWD) of the transmitter (A) has reached the set transmitter (A) limit (FWDJJMIT) value (106), writing the error message display (4) (105) if the output power has reached the set transmitter (A) limit value (105) (Because the output power limit has been reached in the test stage where the lowest power should be output.), if the output power has not reached the set limit value of the transmitter (A), increasing the voltage value in 1 V intervals (108), checking whether it reaches the entered maximum voltage value (107), when the voltage maximum value is reached, by increasing the modulator (5) output power (P Mod) by 1dB intervals (109), checking whether the transmitter (A) output power has reached the set limit value and modulator (5) output power has reached the set limit (P_TEST_MAX) value (110,111), - recording the efficiency, voltage, and modulator (5) output power values when the transmitter (A) output power reaches the set limit value (112) checking whether the voltage value reaches the minimum voltage value entered by reducing the voltage value by 1 V intervals (113) (114), recording voltage and modulator (5) output power values where the transmitter (A) output power reaches the set limit value (115) by increasing the output power of the modulator (5) by 1 dB intervals until the voltage reaches the minimum value (109), recording voltage and modulator (5) output power values for best efficiency among recordings and operating the transmitter (A) at these values (116), - if no voltage and modulator (5) output value has been reached to the set transmitter (A) limit value, recording the maximum voltage and modulator (5) output values and operating the transmitter (5) at these values so that the transmitter (5) works at the highest power that it can operate (117).