JP3083327U - High power short-wave charging credit transmitter by semiconductor - Google Patents

Abstract

(57) [Summary] (Modifications required) [Problem] To reduce the cost of manufacturing, reduce the cost, and achieve high reliability and reduction of operating costs by completing a simple circuit for an electronic radio transmitter for the short wave band of amateur radio. Achieve. SOLUTION: By using a bipolar transistor for medium output power amplification as an active element of a crystal oscillation circuit, an oscillation output of a level capable of widening a variable width of an oscillation frequency and sufficiently driving a power amplification section of the next stage. And RF power of 100 W or more can be supplied to the load from the power amplifier.

Description

[Detailed description of the invention]

[Technical field to which the present invention pertains] The present invention combines a crystal oscillator with one transistor and a power amplifier with one power MOSFET, and can generate RF power of about 100 W to about 150 W at a voltage of 30 V. This is related to the transmitter of short-wave charging credit for low band.

2. Description of the Related Art In a short-wave band, in order to generate RF power of 100 W or more in a semiconductor circuit, a circuit having three to four stages is required, and power supply efficiency is poor.

[Problems to be Solved by the Invention] If there are three to four stages from the oscillation circuit to the power amplifier circuit, many parts are required first, and the power supply efficiency also deteriorates. As the number of components increases, the failure rate increases, and both the board and the finished product increase. The cost increases. Therefore, if RF power of 100 W or more can be generated only by oscillation and power amplification, the number of components used is small, the power efficiency (90% or more) is good, the size is small and light, and unnecessary heat generation is reduced. This is what we are trying to solve.

[Means for Solving the Problems] In the present invention, drive power of 2 W or more is generated in the oscillation stage so that the output of the crystal oscillator can sufficiently drive the power MOSFET of the power amplifier. Instead of using a small signal transistor dedicated to oscillation as in the past, a drive stage for audio or a power transistor for small output is used, and the oscillation frequency can be shifted by 50 KHz or more by a VXO circuit. Thing. With this 2 W drive output, a power amplifier using one inexpensive power MOSFET can be driven, and an RF output of 100 W or more can be obtained with a drain voltage of 30 V.

[0007] [Embodiment of the Invention] [0007] The oscillation circuit is a Pierce BE oscillation circuit that combines a variable condenser and an inductor in series with a crystal to form a VXO circuit that can vary the oscillation frequency between about 50 KHz. . Therefore, the band of the telegraph band in the low band of amateur radio can be covered. Oscillation transistors can be used for small output power stones with FT of 100 MHz or more and base spreading resistance of 10 ohms for both NSC type and 2SC type or 2SD type transistors. A tuning circuit is provided on the output side to supply drive power with less harmonics to reduce spurious. The power amplifier is a high-bandwidth amplifier using a ferrite transformer for the input and output. The elements used are general-purpose power MOSFETs for DDC and Motor-D, which are used with source grounding.

[Embodiment] An embodiment will be described below with reference to the accompanying circuit diagrams. This circuit is a high-efficiency high-output telegraph transmitter that can cover 7000 KHz to 7028 KHz in the 7-MHz band telegraph mode in amateur radio. First, the crystal used is an off-the-shelf inexpensive nameplate with 7030 KHz. Bias of the oscillation circuit is fixed bias, it is wired to the base for Q ₁ via a 10K ohm from + Vcc. The oscillation frequency adjustment variable capacitor has a withstand voltage of 500 volts and an electrostatic capacitance of 150 pF. By changing these values, the oscillation frequency is changed. The inductor in series with the variable capacitor makes it easy to change the oscillation frequency. During oscillation, power is supplied from the collector of the PNP transistor of Q2 via a tuning coil to the collector of Q _1, at the same time bias consuming. Transistor of Q ₂ is the switching element at the time of Kyidau down. Transistors and ZD ₁ of Q ₃ are a stabilization circuit of the voltage applied to the _{Q 1.} The tuning circuit is a coil wound with a dust core and a 0.1 mm urethane wire. Dip mica is used for the resonance capacitor.

[0007] [Description of the telegraph key Circuit oscillation intermittently is performed by on-off of the power of _{Q 1.} Dropping to the ground from the base Q ₂ 'via a 1K ohm, voltage transistor Q _2' is stabilized from the emitter over and turned on to oscillate being fed to Q _1.

[Explanation of Power Amplification] Power amplification is a broadband amplifier using a 4: 1 ferrite transformer for an input section, a 1: 1 ferrite transformer for an output section, and a power MOS FET for a transistor. Is a very inexpensive general-purpose element for DDS and Motor-D. The voltage of the unstabilized power supply is applied to the drain of this FET during transmission by turning on the toggle switch. A capacitor for preventing parasitic oscillation is located between the power supply side of the output section and ground. The source is grounded. The coupling capacitor comes out of the drain and follows the low-pass filter.

[Explanation of Low-Pass Filter] A pie-type low-pass filter is simply combined in two stages. The corner frequency is about 10 MHz.

[Description of Transmission / Reception Switching Circuit] Although this is inconvenient due to the operation of the transmission / reception switching relay due to opening and closing of the toggle switch, damage to the transmission / reception circuit due to malfunction can be prevented. [Effects of the present invention] As described above, the transmitter dedicated to telecommunications of the present invention has a very simple circuit configuration, and can be easily maintained and managed by the user himself. In addition, since no integrated circuit is used, it is possible to transmit a very clean radio wave without any high frequency interference. Since a crystal oscillator is used for the signal source, it is advantageous in terms of spurious. Since no buffer is inserted, wasteful power consumption at this stage can be saved, and the number of parts can be reduced, so that the size and weight can be reduced. The power supply voltage supplied to this transmitter is wide in the range of 18 to 60 volts. At any time, it can be drawn from the +/- terminals of the electrolytic capacitor of the existing 13.8 volt output stabilized power supply and supplied to this transmitter, but the zener diode of the oscillation circuit should be replaced according to the capacity of the power supply. Although it is necessary, the existing power supply can be used, reducing the economic burden on the user. Since the power supply efficiency is 90% or more, the operating cost is low and the burden on the environment is reduced.

[Brief description of the drawings]

[Explanation of circuit diagram] It is a circuit diagram showing one embodiment of the electronic credit transmitter of the present invention.

[Explanation of symbols]

Q12SC1964, etc. Tr Q22SK2233, etc. FET Q3 2SA715, etc. Tr Q4 2SD1266, etc. Tr ZD1 20V500mW, Zener diode X 7030KHz Crystal VC 150pF Varicon C1 470pF Mica capacitor withstand voltage 50V C2 1500pF Mica capacitor withstand voltage 50V C3 70pF Mica capacitor withstand voltage 50V C4 0.01mF Ceramic capacitor withstand voltage 50V C5 1mF1F5V C5 1mF1T5C1T5C1T5C1T1C Withstand voltage 50V C7 0.1mF Ceramic capacitor Withstand voltage 50V C8 1800pF Mica capacitor Withstand voltage 500V C9 680pF Mica capacitor Withstand voltage 500V C10 470pF Mica capacitor Withstand voltage 500V R1 10K ohm 1 / 4w R2 18 ohm 1 / 2W R3 1K ohm 1 / 4W R4 Ohm 1 4W T1 core containing the bobbin winding ratio of the primary side 10 turns,
5 turns on the secondary side Wire diameter 0.2mm urethane wire, core diameter 8mm T2 Ferrite core FT50-61 material wound 5 times by bifilar winding. Uses an enamel wire with a wire diameter of 0.3 mm. T3 Ferrite core FT114-61 material wound 6 times by bifilar. Use a linear 0.5mm Teflon wire. . L1 carbonyl toroidal core T68-2 material has a linear 0.1 mm urethane wire wound 100 times. L2 carbonyl toroidal core T68-2 material has a linear 0.4 mm enamel wire wound 14 times. L3 Carbonyl toroidal core T68-2 material: 14 turns of linear 0.4 mm enameled wire. Ly1 24V specification 1 circuit 2 contacts general purpose relay

Claims (1)

[Utility model registration claims] (1) One transistor is used for each of a crystal oscillator and a power amplifier, and a buffer amplifier is omitted.
A low-cost, low-maintenance transmitter using low-cost semiconductors that can generate 100 W of RF power at 0 V.