The CD4069 or 74C04 hex inverter—is used as^ fixed-frequency oscillator centered around 100 kHz. U2 contains the variable frequency oscillator and balanced modulator. The CD4046 is a phase-locked loop and R3, R4, and C2 determine the center frequency of....

IC-1 and the associated circuitry form a stable audio tone generator that feeds a buffer amplifier, Ql and Q2. The tone output is taken from the emitters of the transistor pair to supply a carrier voltage for a balanced modulator made up of four diodes—Dl....

Two IC rf modulators convert a suitable baseband video and audio signal up to a low VHF modulated carrier-Channel2 through 6 in the U.S., and 1 through 3 in japan-the LM1889 and the LM2889. Both !Cs are identical regarding the rf modulation function,....

This circuit passes the input signal at unity gain, either unchanged or inverted, depending on the digital control input. A buffered input is shown, since low-source impedance is essential. Gain can be added by modifications to the feedback networks.....

The three schematics represent three building blocks for a 10-meter SSB transmitter. Or these blocks can be used separately as circuit modules for other transmitters. The VFO board uses an FET transmittal oscillator, the VFO signal is mixed in an NE602....

This circuit uses two balanced modulators to produce a DSB signal and then reinsert the carrier, except t..

The NE592 is connected in conjunction with a MC1496 balanced modulator to form an excellent automatic gain control system. The signal is fed to the signal input of the MC1496 and re-coupled to the NE592. Unbalancing the carrier input of the MC1496 causes....

Amplifying and limiting of the AM carrier is accomplished by the if gain block providing 55 dB of gain or higher with a limiting of 40 µ\. The limited carrier is then applied to the detector at the carrier ports to provide the desired switching function.....

When the carrier level is adequate to switch the cross-coupled pair of differential amplifiers, the modu· lation signal, which has been applied to the gate, will be switched at the carrier rate, between the collector loads. When switching occurs, it will....

A complete schematic diagram of the voice disguiser is shown. Microphone MIC1 picks up the voice signal and feeds it to an audio amplifier, consisting of Ql and Q2, and a few support components. The amplifier has a low-pass gain response that limits the....

Common diode balanced modulator circuit is shown. It consists of two identical performance diodes and a center-tapped transformer T composition. Diodes VD1, VD2 are 2AP9. Other..

Currently, high-quality communications receiver in the use of diode ring mixers and mixer by a double differential pair balanced modulator constituted, set into an analog multiplier (MC1496)..

Combines signals from loop and sense antennas of automatic direction finder, to give 130-cps output having correct phase for driving rotor of resolver to null position.-P. V.Sparks, Servo Filter and Gain Control lmprove Automatic Direction Finder,....

A very simple FSK demodulator for the 2025 Hz and 2225 Hz can be designed using the LM565 which is a general purpose phase locked loops IC containing a stable, highly linear voltage controlled oscillator for low distortion FM demodulation, and a double....

AF modulating signal is applied to gates of matched FETs in push-pull through T1 having accurately center-tapped secondary, and RF carrier is applied to sources in parallel through C3. Carrier is canceled in output circuit, leaving two sidebands. R3 is....

Circuit detail is shown in figure 3. The main elements of the system are a speech amplifier, the audio phase shift network with balanced driver circuit (N1A, N2A), two balanced modulator stages (N1B & N2B), an RF carrier phase shift circuit (N3) and an....

Mixers (sometimes known as frequency converters), modulators, balanced modulators and other circuit blocks are considered below. Each works on the same basic principles. A mixer circuit normally has two inputs - from two separate signal sources. In the....

A Left and Right source of audio are first pre-emphasized (HPF) and then fed to adder circuits. The output of one adder is the sum of the two signals, or the L + R signal (the monaural signal), and the output of the other adder is the difference of the two....

The LT5575 is an 800MHz to 2. 7GHz direct conversion quadrature demodulator optimized for high linearity receiver applications. It is suitable for communications receivers where an RF signal is directly converted into I and Q baseband signals with bandwidth....

A very simple single sideband (SSB) suppressed carrier demodulator (product detector) circuit can be designed using the LM1596 balanced modulator-demodulators IC. The carrier signal is applied to the carrier input port with sufficient amplitude for switching....

Mullard TCA240 dual balanced modulator-demodulator provides suppression of carrier frequency at output, as required for SSB or DSB operation of transmitter. Bias resistor R7 is adjusted for minimum carrier output to correct imbalance. Can be used as....

When the carrier level is adequate to switch the cross-coupled pair of differential amplifiers, the modulation signal, which has been applied to the gate, will be switched at the carrier rate, between the collector loads. When switching occurs, it will....

Achieves high carrier and modulation suppression by using closely matched diodes and providing R1 for amplitude adjustment and coaxial line for phase adjustment. R2 provides slight amplitude adjustment. -W. H. Ellis, Diode Quad Modulator Suppresses Carrier....

The circuit uses easily available components. Most of the coils are wound on low cost balun core. The circuit uses ladder filter. Filter is build around four numbers of 4.43 MHz crystals. I used ladder filter because it is cheap and getting reasonably good....

A simple, low component count phase locked loop that locks onto and detects the amplitude of an incoming baseband 7 bit Barker code using a switched resistor demodulator that is driven directly by a microcontroller's output pins. Balanced modulators using....