JPS6052137A - Amplitude modulation stereophonic receiver - Google Patents

Abstract

PURPOSE:To obtain an AM stereophonic receiver possible for replacement by adopting cartridge type for a decoder circuit. CONSTITUTION:A cartridge 6 is inserted into a casing 1 on a front panel 1a. Then a board of the decoder circuit 30 is contained in a casing 9 of the cartridge 6 and a connector 8 to be connected to the other circuit is projected externally from the rear part of the casing 9. Further, an indicator 7 is lighted when the cartridge 6 is inserted to the casing 1. The circuit 30 is a circuit replaceable respectively depending on each system and transmits a left sound signal L to a line l7 and a right sound signal R to a line l8, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an amplitude modulation (AM) modulation stereo receiver, and more specifically, a decoder circuit that can be replaced depending on the transmission/1G system of each broadcasting station. The present invention relates to an AM modulated stereo receiver having an AM modulated stereo receiver.

Background Art Currently, there are five AIJ stereo broadcasting systems: the Magnavox system, the Harris system, the Kahn/Bezelchin system (cart system), the Motorola system, and the Vera system. The Magnavox method converts the carrier wave into sub-signals (I, -
The phase degree is modulated by R), and the amplitude is modulated by dr4 L and the main signal (L+R). In the Harris method, i self-crossing and ν11 are performed on the carrier wave Kemain sub-18, but in order to prevent deterioration of the distortion rate during mono reception, the sub-signal modulation double-tone tanl 5°=
In order to prevent deterioration of the S/N ratio, a method is adopted in which the modulation rate is suppressed to 0.268 and the modulation rate at the time of a small level sub-signal is increased. In the Kahn/Bezelchin system, the carrier wave is subdivided by all sub-18 carrier waves, and the main signal is modulated, but the 1li
A phase difference of 90° is established between the IlilT and left and right L-R.
The iH component kl'J is separated into both sidebands. Furthermore, a compensation system to reduce distortion of sub-signals during stereo demodulation? It is added. In the Motorola system, the carrier wave is orthogonally modulated with the main and sub signals, passed through a limiter to remove all of the amplitude modulation, and then amplitude modulated again with the main signal. In the Vera type, the carrier wave is frequency-modulated with a sub-signal and amplitude-modulated with a main signal. Note that the sub-signal is pre-emphasized with a time constant of 400 μs.

Conventionally, the decoding circuit provided in AM stereo receivers performs m-+ on the left and right audio signals of the stereo playback sound, but if the transmission method of the broadcasting station differs, the decoding circuit must be installed according to the transmission method. No. It is difficult to standardize decoding circuits, and a receiver compatible with all five systems becomes too expensive.

Additionally, broadcasting stations tend to stick to one method of transmission depending on the region. Therefore, as a user, it is sufficient to receive a message sent by one or three transmission methods.

OBJECTS An object of the present invention is to solve the above-mentioned technical problems and to provide a complete AM stereo receiver that can be installed in which the entire decoder circuit is a cartridge type.

Example FIG. 1 is a trunk view of one embodiment of the present invention.

A front panel 1a of the casing 1 is provided with a display 2 for displaying all broadcast reception frequencies, a volume adjustment volume 3, a frequency selection volume 4, and a sound quality adjustment volume 5.

Further, on the front panel 1a, a cartridge 6 is inserted into the casing 1, and a board for a decoder circuit (described later) is housed in the casing 9. The indicator 7 projects outward from the rear.The indicator 7 lights up when a stereo broadcast is received, or lights up when a cartridge 6 compatible with the transmission system of the broadcasting station is inserted into the casing 1.

FIG. 2 is a block diagram showing the configuration of an electric circuit housed in the casing 1 of FIG. 1. The high frequency signal transmitted from the broadcasting station is transmitted through the antenna 21 and the line 11? The signal is applied to the high frequency circuit 22 via the signal. The high frequency circuit 22 selects high frequency signals from all desired broadcast stations and amplifies the high frequency signals. The high frequency signal from the high frequency circuit 22 is given to the mixing circuit 23 via the line 12'c, and is converted into an intermediate frequency signal by the signal from the local oscillation circuit 24. The intermediate frequency signal from the mixing circuit 23 is on line 1
3 to the intermediate frequency circuit 25. The intermediate frequency signal amplified by the intermediate frequency circuit 25 is transmitted to the line 14'jc
Amplitude modulation detection circuit 26 and phase modulation detection circuit 2
7 is given.

The amplitude modulation detection circuit 26 performs full amplitude detection of the intermediate frequency signal applied via the line 14, and provides the amplitude detection signal to the decoder circuit 30 of the cartridge 9 via the line 12'c. The phase modulation detection circuit 27 is connected to the line I! All phases of the intermediate frequency signals applied through the four lines are detected, and the phase detected signals are applied to the decoder circuit 30 of the cartridge 9 through all lines 16. The pilot detection circuit 31 detects the received sound of stereo broadcasting and lights up the light emitting diode 32g. The indicator 7 shown in FIG.
T-Using. The decoder circuit 30 is a circuit that can be replaced separately according to the five methods described above (Magnavox method, Liss method, Kahn/Bezelchin method, Motorola method, Vera one-way method), and the left audio signal is sent to line 7!7. The right side audio signal Rk is sent out on line 18. The left audio signal is amplified by a power amplification circuit 28,
The signal is applied to the speaker 33 via the line 19 and converted into audio. The right side audio signal R is amplified by the power amplification circuit 29, and the right side audio signal R is amplified by the power amplification circuit 29, and the line I! 10vil- to the speaker 34, and is audible. Therefore, it is possible to listen to music broadcasts from the desired broadcasting station in stereo sound.

FIG. 3 shows the electrical configuration of another embodiment of the present invention. FIG. The high frequency signal transmitted from the broadcasting station is sent to the high frequency circuit 3 via the antenna 31 and the line 131'i.
given to 2. In the high' frequency 1 envelope 32, a high frequency signal from a broadcasting station desired to be listened to is selected and the high frequency signal is amplified. The high frequency signal from the high frequency circuit 32 is applied to the mixing circuit 33 via the line /32i, and is converted into an intermediate frequency signal by the signal from the local oscillation circuit 34.

The intermediate frequency signal 1 from the mixing circuit 33 is connected to the line /32i
The signal is applied to the intermediate frequency circuit 35 via the intermediate frequency circuit 35. Intermediate frequency circuit 3
The intermediate frequency signal amplified in step 5 is sent to amplitude modulation detection circuit 36 and phase variation Hr4 detection circuit 3 via line 135'z.
7 is given.

The amplitude 11'iA modulation wave circuit 36 detects the full amplitude of the intermediate frequency signal applied via the line /32i, and converts the amplitude detected signal ? It is applied via line 136 to decoder circuit 44 of cartridge 49. The phase detection circuit 37 detects all phases of the intermediate frequency signal applied via the line 135'e, and provides the phase detection signal to the decoder circuit 44 of the cartridge 49 via the line 137k.

Further, the phase detection signal from the phase detection circuit 37 is
38', the signal is applied to a Magna type 1-type detection circuit 38, a Vera type 1-type detection circuit 39, a cart-car type detection circuit 40, a Motorola type detection circuit 41, and a Harris type detection circuit 42. The valley outputs of the detection circuits 38 to 42 are connected to line 1.
39 to 143 are connected to the coincidence detection circuit 43, respectively. The coincidence detection circuit 43 turns on the light emitting diode 50 (i7) when the content of the decoder circuit 44 of the cartridge 49 is 0, which is suitable for the broadcasting station's transmission system.

The decoder circuit 44 is a circuit that can be replaced separately according to the above-mentioned five methods (Magnavox method, Harris method, Kahn/Hesseltine method, Motorola method, Vera one-way method), and all the left audio signals are sent to the line 145. , the right f voice signal R? on line 144? to send. The left 1lf11 audio signal 1 is amplified by the vehicle power amplification circuit 45 and sent to line 1.
46? The signal is sent to the speaker 47 via the speaker 47, and is converted into audio.

The right side audio signal R is amplified by the power amplification circuit 46, is given to the speaker 48 via the line 147, and is converted into audio. Therefore, the transmission method from the broadcasting station and the cartridge 4
When the numbers 9 and 9 match, the light emitting diode 50 lights up, and it is possible to listen to audio broadcasts from broadcasting stations with stereo sound.

Effects As described above, according to the present invention, the decoder circuit can be replaced depending on the transmission method of the broadcasting station, so the user only has to purchase a decoder circuit that matches the broadcasting station he or she wants to listen to. Receiver k t+! People can.

[Brief explanation of drawings]

Fig. 1 is a shaved perspective view of an embodiment of the present invention;
Is the figure an electrical configuration of another embodiment of the present invention? FIG. 22.32... Cylindrical frequency circuit, 23.33... Mixing circuit, 25, 3.5... Intermediate station θU circuit, 26, 36
・・・Shinyaku Shun 11AI detection circuit, 27.37...(S
'l Comparative harmonic detection circuit, 30.44... Decoder circuit agent Attorney ± 1] L1 failure part

Claims (1)

[Scope of Claims] A high-frequency circuit that fully returns and amplifies a high-frequency signal from a broadcasting station that you want to listen to, a mixing circuit that converts all of the high-frequency signals from the high-frequency circuit into an intermediate frequency signal, and an intermediate frequency signal from the mixing circuit. 1t - An intermediate frequency circuit that amplifies, an amplitude modulation detection circuit that detects the full amplitude of the intermediate frequency signal from the intermediate frequency circuit, a phase detection circuit that detects the full phase of the intermediate frequency signal from the intermediate frequency 1q path, and amplitude modulation detection. An amplitude modulation stereo receiver including a decoder circuit that decodes the output from the circuit and the output from the phase detection circuit and separates the stereo playback sound into a left audio signal and a right audio signal, A temperature-variable amplitude stereo receiver that can be replaced depending on the transmission method of the broadcasting station.