test transmitter for receiver alignment

26 test transmitter for receiver alignment L7 L8 IL9 IL1O IL11 IL12 C8.1. =22n C7 15p 2x BF 494 T1 T2 L6 L5 IL4 IL3 IL2 IL1 1.2m 13. 3m 11Om 133m elektor july/august 1980 7-19 No doubt there are quite a few readers who would like to have a simple test transmitter at their disposal in order to be able to correctly tune his/her receiver, without, of course, having to pay the earth for it. The test transmitter described here seems likely to be a reasonable solution at a reasonable price. Its advantages include: — a wide frequency output, divided into 12 ranges; — a constant output amplitude over the full range; low distortion; — simple frequency switch; — 50 12 output impedance. The block diagram is given in figure 1. As shown, the device consists of two parts, that is to say, a differen- tial amplifier/oscillator with a tuned LC circuit, which generates the high frequency signal, and an amplitude modulator with a built-in 1000 Hz generator. The circuit diagram for the test t...