JPS5931798B2 - FM signal recording level setting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording level setting device for FM signals such as FM broadcasting, and is capable of easily and accurately setting the optimum recording level by detecting the point where the output distortion rate of the recorder is minimum. This is how it was done.

Conventionally, when recording FM broadcasts on a recorder, the recording level was set based on intuition, so it was difficult to record at the optimum level.

It was difficult to set the sound level accurately. The present invention provides an FM signal recording level setting device that eliminates such problems. An embodiment of the present invention will be described below with reference to the drawings. In Figure 1, 1 demodulates the FM signal. demodulator, 2 is 100 of the FM signal
A reference oscillator that oscillates at the same signal level as the signal level during % modulation, 3 is a switch that switches between the output of demodulator 1 and the output of reference oscillator 2, and 4 is a variable that changes the level of the signal taken out by switch 3. volume, 5 is the recorder, 6
and T are the recording input terminal and playback output terminal of the recorder 5,
8 is a comparator that compares the playback output of the recorder 5 and the output of the reference oscillator 2 to detect the output distortion of the recorder 5 and generates an output according to this distortion; 9 is the output of the comparator 8; This is a meter driven by. In the above configuration, when setting the recording level, the switch 3 is switched to the reference oscillator 2 side.

Then, the level of the signal obtained via the switch 3 is varied using a volume 4, and the output thereof is recorded on a recorder 5 via a recording input terminal 6. Then play the recorder 5,
When the obtained reproduction output and the output of the reference oscillator 2 are compared by the comparator 8, an output corresponding to the distortion of the output of the recorder 5 is obtained, and a meter 9 is driven by this output. Therefore, if you gradually increase the recording input level by operating the volume 4, the pointer of the meter 9 will swing according to the curve shown by the solid line in Figure 2. By observing and finding the point where the output distortion rate of the recorder 5 is minimum, the optimum recording level is set.

Incidentally, the broken line in FIG. 2 indicates the input/output characteristics of the recorder 5. After setting the optimum recording level in this way, if the switch 3 is connected to the demodulator 1 side, the demodulated output of the FM signal is recorded at the optimum recording level.

As described above, according to the present invention, when recording an FM signal, the recorder can be easily and accurately adjusted to the optimum recording level, regardless of variations in the output distortion rate of the recorder or differences in the output distortion rate of the recording tape. This has the advantage of being configurable.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an FM signal recording level setting device according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of its operation. 1...Demodulator, 2...Reference oscillator,
3...Switch, 4...Polyum, 5...Recorder, 8...Comparator,
9...Meter.

Claims (1)

[Claims] 1. A reference oscillator that oscillates at the same signal level as the signal level at 100% modulation of the FM signal, a volume that varies the level of the output of the reference oscillator, and the output of the volume that is recorded on a recorder and then played back. FM comprising: a comparator that compares the obtained output with the output of the reference oscillator and generates an output according to the output distortion rate of the recorder; and a meter driven by the output of the comparator. Signal recording level setting device.