User manual SENNHEISER SER 1-3

[. . . ] dipole (10 m above ground) at the receiver. Consequently the transmitter can be used as an intensified wireless microphone for location work of radio and TV broadcasting stations. To address a larger number of receivers as it is necessary for different applications e. Microphone, modulation line or data converter) and the desired antenna should be connected to the corresponding sockets. [. . . ] Therefore, it is somewhat difficult to recharge a partially discharged accumulator to its nominal capacity. During the time of the check a load is connected to the battery. the recharging will be continued until the voltage of the loaded accumulator reaches the nominal value. When the charging process is finished, the battery is automatically disconnected. The charging starts again when the voltage has dropped below a defined value. Therefore, the baHeries can remain at the charger Tor an unlimited period of time without supervision. Zum Wechsel des Batteriekastens werden die sichtbaren Münzenschlitz8 mitter should be adjusted by means of the deviation control such that at volume peaks the pointer of the instrument remains below 40 divisions of the scale when the dynamic range of the transmitted signal shall be preserved, When the volume at the receiver should remain constant to a certain extent the pointer must be kept around 50 divisions, When the transmitter is working the selector switch can be set to that position which seems to be most useful for the supervision of the operating condition e. The transmitter SER 1 is a frequency modulated transmitter with a RF power of 1 W. It can be modulated by means of a microphone or through a 200 Q line. The transmitter is intended for radiotelephony with a deviation of 15 kHz or for reporting purposes with 75 kHz deviation. The microphone input (Bu 1) or the line input (Bu 2) are connected to the amplifier via the selector switch (S 1). This dc voltage is used as a control voltage for regulating of the differential resistance of two antiparallel connected diodes (0" 03). These diodes affect the negative feedback from T2 to TL The necessary balance of the control voltage is achieved by means of transistor T5 and the zener diode 09. With decreasing sensitivity of the amplifier according to the setting of p, the range of the automatic gain control decreases too (see figure on page 16). The switch S, changes the frequency to obtain the second carrier frequency. The oscillator frequency is doubled by means of T7 and connected to two separator stages TB and T17. Its frequency can be alte red by switching over of the crystals 0, and 0, . The diHerence or the two frequencies is used as an intermediate frequency which is ampliried by T16, T'5, T14. The following discriminator changes the IF signal into a control voltage which depends on the frequency shift or the free-running oscillator. From the last IF stage T'4 a voltage is taken off, rectified by diode 0, 6 and red to the measuring instrument. The presence of this voltage indicates that the IF signal is produced and, hence, the working of the electronic frequency lock-in of the free-running oseillator. The RF power amplifier is iinked to the output of the separator stage T8. [. . . ] If a difference occurs correct the alignment of the RF amplifier. disconnect the short-circuit between test points Band C and start the crystal-controlled oscillator. The core of Ln is screwed so far into the coil until the oscillator works. The working condition is clearly recognizable because the IF signal occurs and the control instrument shows a deflection in position "FREQ". [. . . ]