Mc1496,Mc1496B able 1. voltage Gain and output Frequencies Carrier Input Signal (Vc) Approximate Voltage Gain Output signal Frequency(s) LOw-level dc () fM High-level dc RL RLC(ms) LOw-level ac 22(x)(R=+2e fc±f 0637R 毛±fM,3fc±fMs,5fc±f 4. All gain expressions are for a single-ended output. For a differential output connection, multiply each expression by two esista 7. tE Transistor dynamic emitter resistance, at 25G re=26 mv es Kelvin, q= the charg The gain from the modulating signal input port to the All that is required to shift from suppressed carrier to AM output is the MC1496 gain parameter which is most often of operation is to adjust the carrier null potentiometer for the interest to the designer. This gain has significance only when proper amount of carrier insertion in the output signal the lower differential amplifier is operated in a linear mode However, the suppressed carrier null circuitry as shown in es most applications of the dev Figure 26 does not have sufficient adjustment range As previously mentioned, the upper quad differential Therefore, the modulator may be modified for AM amplifier may be operated either in a linear or a saturated operation by changing two resistor values in the null circuit mode. Approximate gain expressions have been developed as shown in Figure 27 for the MC1496 for a low-level modulating signal input and the following carrier input conditions Product Detector 1)Low-level dc The MC1496 makes an excellent SSB product detector 2)High-level dc (see Figure 28) 3)Low-level ac This product detector has a sensitivity of 3.0 uV and a 4)High-level ac dynamic range of 90 dB when operating at an intermediate frequency of 9.0 MHz basic application of the MC1496. The suggested circuit for amplifier input impedan k as o"% These gains are summarized in Table 1, along with the The detector is broadband for the entire high frequency frequency components contained in the output signal range For operation at very low down to 50 kHz the 0. 1 uF capacitors on Pins 8 and 10 should APPLICATIONS INFORMATION be increased to 1.0 uF. Also, the output filter at Pin 12 can Double sideband suppressed carrier modulation is the be tailored to a specific intermediate frequency and audio this application is shown on the front page of this data sheet. As in all applications of the MC1496, the emitter In some applications, it may be necessary to operate the resistance between Pins 2 and 3 may be increased or MC1496 with a single dc supply voltage instead of dual decreased to adjust circuit gain, sensitivity, and dynamic supplies. Figure 25 shows a balanced modulator designed range for operation with a single 12 Vdc supply Performance of this circuit is similar to that of the dual supply modulat introducing carrier signal at the carrier input and an AM AM Modulator signal at the SSB input The carrier signal may be derived from the intermediate The circuit shown in Figure 26 may be used as an frequency signal or generated locally. The carrier signal may mplitude modulator with a minor modification httpllonsemi.comMC1496, MC1496B http://onsemi.com 9 Table 1. Voltage Gain and Output Frequencies Carrier Input Signal (VC) Approximate Voltage Gain Output Signal Frequency(s) Low−level dc RL VC 2(RE
2re) KT q fM High−level dc RL RE
2re fM Low−level ac RL VC(rms) 2 2 KT q (RE
2re) fC ± fM High−level ac 0.637 RL RE
2re fC ± fM, 3fC ± fM, 5fC ± fM, . . . 2. Low−level Modulating Signal, VM, assumed in all cases. VC is Carrier Input Voltage. 3. When the output signal contains multiple frequencies, the gain expression given is for the output amplitude ofeach of the two desired outputs, fC + fM and fC − fM. 4. All gain expressions are for a single−ended output. For a differential output connection, multiply each expression by two. 5. RL = Load resistance. 6. RE = Emitter resistance between Pins 2 and 3. 7. re = Transistor dynamic emitter resistance, at 25°C; re  26 mV I5 (mA) 8. K = Boltzmann′s Constant, T = temperature in degrees Kelvin, q = the charge on an electron. The gain from the modulating signal input port to the output is the MC1496 gain parameter which is most often of interest to the designer. This gain has significance only when the lower differential amplifier is operated in a linear mode, but this includes most applications of the device. As previously mentioned, the upper quad differential amplifier may be operated either in a linear or a saturated mode. Approximate gain expressions have been developed for the MC1496 for a low−level modulating signal input and the following carrier input conditions: 1) Low−level dc 2) High−level dc 3) Low−level ac 4) High−level ac These gains are summarized in Table 1, along with the frequency components contained in the output signal. APPLICATIONS INFORMATION Double sideband suppressed carrier modulation is the basic application of the MC1496. The suggested circuit for this application is shown on the front page of this data sheet. In some applications, it may be necessary to operate the MC1496 with a single dc supply voltage instead of dual supplies. Figure 25 shows a balanced modulator designed for operation with a single 12 Vdc supply. Performance of this circuit is similar to that of the dual supply modulator. AM Modulator The circuit shown in Figure 26 may be used as an amplitude modulator with a minor modification. All that is required to shift from suppressed carrier to AM operation is to adjust the carrier null potentiometer for the proper amount of carrier insertion in the output signal. However, the suppressed carrier null circuitry as shown in Figure 26 does not have sufficient adjustment range. Therefore, the modulator may be modified for AM operation by changing two resistor values in the null circuit as shown in Figure 27. Product Detector The MC1496 makes an excellent SSB product detector (see Figure 28). This product detector has a sensitivity of 3.0 V and a dynamic range of 90 dB when operating at an intermediate frequency of 9.0 MHz. The detector is broadband for the entire high frequency range. For operation at very low intermediate frequencies down to 50 kHz the 0.1 F capacitors on Pins 8 and 10 should be increased to 1.0 F. Also, the output filter at Pin 12 can be tailored to a specific intermediate frequency and audio amplifier input impedance. As in all applications of the MC1496, the emitter resistance between Pins 2 and 3 may be increased or decreased to adjust circuit gain, sensitivity, and dynamic range. This circuit may also be used as an AM detector by introducing carrier signal at the carrier input and an AM signal at the SSB input. The carrier signal may be derived from the intermediate frequency signal or generated locally. The carrier signal may